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1) A localized group of organisms that belong to the same species is called a
2) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into
A) the energy of motion.
B) carbon dioxide and water.
C) the potential energy of chemical bonds.
E) kinetic energy.
Which of the following statements is representative of the second law of thermodynamics?
A) Conversion of energy from one form to another is always accompanied by some gain of free energy.
B) Heat represents a form of energy that can be used by most organisms to do work.
C) Without an input of energy, organisms would tend toward decreasing entropy.
D) Cells require a constant input of energy to maintain their high level of organization.
E) Every energy transformation by a cell decreases the entropy of the universe.
4) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope?
5) To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology?
B) emergent properties
D) the cell theory
E) feedback regulation
6) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation?
A) a bioinformatic system
B) positive feedback
C) negative feedback
D) feedback inhibition
E) enzymatic catalysis
7) When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of
A) catalytic feedback.
B) positive feedback.
C) negative feedback.
D) bioinformatic regulation.
E) protein-protein interactions.
8) Which branch of biology is concerned with the naming and classifying of organisms?
B) schematic biology
9) Prokaryotic and eukaryotic cells generally have which of the following features in common?
A) a membrane-bounded nucleus
B) a cell wall made of cellulose
D) flagella or cilia that contain microtubules
E) linear chromosomes made of DNA and protein
10) Prokaryotes are classified as belonging to two different domains. What are the domains?
A) Bacteria and Eukarya
B) Archaea and Monera
C) Eukarya and Monera
D) Bacteria and Protista
E) Bacteria and Archaea
11) Global warming, as demonstrated by observations such as melting of glaciers, increasing CO2 levels, and increasing average ambient temperatures, has already had many effects on living organisms. Which of the following might best offer a solution to this problem?
A) Continue to measure these and other parameters of the problem.
B) Increase the abilities of animals to migrate to more suitable habitats.
C) Do nothing; nature will attain its own balance.
D) Limit the burning of fossil fuels and regulate our loss of forested areas.
E) Recycle as much as possible.
12) A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?
13) A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism?
A) domain Bacteria, kingdom Prokaryota
B) domain Archaea, kingdom Bacteria
C) domain Eukarya, kingdom Plantae
D) domain Eukarya, kingdom Protista
E) domain Eukarya, kingdom Fungi
14) Which of these provides evidence of the common ancestry of all life?
A) ubiquitous use of catalysts by living systems
B) near universality of the genetic code
C) structure of the nucleus
D) structure of cilia
E) structure of chloroplasts
What aspects of protein structure are stabilized or assisted by hydrogen bonds?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) secondary, tertiary, and quaternary structures, but not primary structure
What is this structure?
What is this structure?
What is this structure?
What is this structure?
What is this structure?
What is this structure?
15) Which of the following is (are) true of natural selection?
A) It requires genetic variation.
B) It results in descent with modification.
C) It involves differential reproductive success.
D) It results in descent with modification and involves differential reproductive success.
E) It requires genetic variation, results in descent with modification, and involves differential reproductive success.
16) Charles Darwin proposed a mechanism for descent with modification that stated that organisms of a particular species are adapted to their environment when they possess
A) non-inheritable traits that enhance their survival in the local environment.
B) non-inheritable traits that enhance their reproductive success in the local environment.
C) non-inheritable traits that enhance their survival and reproductive success in the local environment.
D) inheritable traits that enhance their survival and reproductive success in the local environment.
E) inheritable traits that decrease their survival and reproductive success in the local environment.
17) Which of these individuals is likely to be most successful in an evolutionary sense?
A) a reproductively sterile individual who never falls ill
B) an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce
C) a male who mates with 20 females and fathers one offspring
D) an organism that lives 100 years and leaves two offspring, both of whom survive to reproduce
E) a female who mates with 20 males and produces one offspring that lives to reproduce
18) In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population before they reproduce. Based on your knowledge of natural selection, you would predict that the average height of the human population will
A) remain unchanged.
B) gradually decline.
C) rapidly decline.
D) gradually increase.
E) rapidly increase.
19) Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by
A) natural philosophy.
C) the hierarchy of the biological organization of life.
D) natural selection.
E) feedback inhibition.
20) What is the major difference between a kingdom and a domain?
A) A kingdom can include several subgroups known as domains.
B) All eukarya belong to one domain.
C) All prokaryotes belong to one domain.
D) The importance of fungi has led scientists to make them the whole of one domain.
E) Only organisms that produce their own food belong to one of the domains.
21) Which of the following best describes what occurred after the publication of Charles Darwin's On the Origin of Species?
A) The book received little attention except from a small scientific community.
B) The book was banned from schools.
C) The book was widely discussed and disseminated.
D) The book's authorship was disputed.
E) The book was discredited by most scientists.
22) Why is Darwin considered original in his thinking?
A) He provided examples of organisms that had evolved over time.
B) He demonstrated that evolution is continuing to occur now.
C) He described the relationship between genes and evolution.
D) He proposed the mechanism that explained how evolution takes place.
E) He observed that organisms produce large numbers of offspring.
23) Darwin's finches, collected from the Galápagos Islands, illustrate which of the following?
A) mutation frequency
B) ancestors from different regions
C) adaptive radiation
D) vestigial anatomic structures
E) the accuracy of the fossil record
24) Which of the following categories of organisms is least likely to be revised?
25) What is the major distinguishing characteristic of fungi?
A) gaining nutrition through ingestion
B) being sedentary
C) being prokaryotic
D) absorbing dissolved nutrients
E) being decomposers of dead organisms
27) According to Darwinian theory, which of the following exhibits the greatest fitness for evolutionary success?
A) the species with the longest life
B) the individuals within a population that have the greatest reproductive success
C) the phylum with members that occupy the greatest number of habitats
D) the community of organisms that is capable of living in the most nutrient-poor biome
E) the organism that produces its own nutrients most efficiently
28) Similarities and differences among/between life-forms over time are most efficiently recorded by scientists in which field(s) of study?
B) paleontology and anatomy
C) paleontology, anatomy, and taxonomy
D) paleontology, anatomy, taxonomy, and genetics
E) paleontology, anatomy, taxonomy, genetics, and ecology
29) Why is the theme of evolution considered to be the core theme of biology by biologists?
A) It provides a framework within which all biological investigation makes sense.
B) It is recognized as the core theme of biology by organizations such as the National Science Foundation.
C) Controversy about this theory provides a basis for a great deal of experimental research.
D) Since it cannot be proven, biologists will be able to study evolutionary possibilities for many years.
E) Biologists do not subscribe to alternative models.
30) The method of scientific inquiry that describes natural structures and processes as accurately as possible through careful observation and the analysis of data is known as
A) hypothesis-based science.
B) discovery science.
C) experimental science.
D) quantitative science.
E) qualitative science.
35) The application of scientific knowledge for some specific purpose is known as
B) deductive science.
C) inductive science.
D) anthropologic science.
E) pure science.
31) Collecting data based on observation is an example of ________; analyzing this data to reach a conclusion is an example of ________ reasoning.
A) hypothesis-based science; inductive
B) the process of science; deductive
C) discovery science; inductive
D) descriptive science; deductive
E) hypothesis-based science; deductive
32) When applying the process of science, which of these is tested?
A) a question
B) a result
C) an observation
D) a prediction
E) a hypothesis
33) A controlled experiment is one in which
A) the experiment is repeated many times to ensure that the results are accurate.
B) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data.
C) there are at least two groups, one of which does not receive the experimental treatment.
D) there are at least two groups, one differing from the other by two or more variables.
E) there is one group for which the scientist controls all variables.
34) Why is it important that an experiment include a control group?
A) The control group is the group that the researcher is in control of, the group in which the researcher predetermines the results.
B) The control group provides a reserve of experimental subjects.
C) A control group is required for the development of an "If…then" statement.
D) A control group assures that an experiment will be repeatable.
E) Without a control group, there is no basis for knowing if a particular result is due to the variable being tested.
What is a control group?
Group or subjects that act as a baseline or demonstrate what would happen if nothing changed
36) Which of the following are qualities of any good scientific hypothesis?
I. It is testable.
II. It is falsifiable.
III. It produces quantitative data.
IV. It produces results that can be replicated.
A) I only
B) II only
C) III only
D) I and II
E) III and IV
37) When a hypothesis cannot be written in an "If…then" format, what does this mean?
A) It does not represent deductive reasoning.
B) It cannot be a scientific hypothesis.
C) The subject cannot be explored scientifically.
D) The hypothesizer does not have sufficient information.
E) It cannot be testable.
38) In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do?
A) Do not show these points but write a footnote that the graph represents the correct data.
B) Average several trials and therefore rule out the improbable results.
C) Show all results obtained and then try to explore the reason(s) for these outliers.
D) Throw out this set of data and try again.
E) Change the details of the experiment until they can obtain the expected results.
39) Which of the following is the best description of a control for an experiment?
A) The control group is kept in an unchanging environment.
B) The control is left alone by the experimenters.
C) The control group is matched with the experimental group except for the one experimental variable.
D) The control group is exposed to only one variable rather than several.
E) Only the experimental group is tested or measured.
40) Given the cooperativity of science, which of the following is most likely to result in an investigator being intellectually looked down upon by other scientists?
A) Making money as the result of studies in which a new medication is discovered.
B) Doing meticulous experiments that show data that contradict what has been previously reported by the scientific community.
C) Spending most of a lifetime investigating a small and seemingly unimportant organism.
D) Getting negative results from the same set of experiments.
E) Being found to have falsified or created data to better fit a hypothesis.
41) Which of these is an example of inductive reasoning?
A) Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic.
B) These organisms live in sunny parts of this area so they are able to photosynthesize.
C) If horses are always found grazing on grass, they can be only herbivores and not omnivores.
D) If protists are all single-celled, then they are incapable of aggregating.
E) If two species are members of the same genus, they are more alike than each of them could be to a different genus.
42) In a high school laboratory, which of the following constitutes an experiment?
I. learning to use a microscope by examining fixed specimens on slides
II. being able to examine swimming protists under a microscope
III. extracting pigments from plant leaves and separating the types of pigments for identification
IV. preparing root tips for examination by staining them
A) I only
B) II only
C) III only
D) II and III only
E) II, III, and IV
43) Which of the following best describes a model organism?
A) It is often pictured in textbooks and easy for students to imagine.
B) It lends itself to many studies that are useful to beginning students.
C) It is well studied, easy to grow, and results are widely applicable.
D) It is small, inexpensive to raise, and lives a long time.
E) It has been chosen for study by the earliest biologists.
44) Why is a scientific topic best discussed by people of varying points of view, a variety of subdisciplines, and diverse cultures?
A) They can rectify each other's approach to make it truly scientific.
B) Robust and critical discussion between diverse groups improves scientific thinking.
C) Scientists can explain to others that they need to work in isolation to utilize the scientific method more productively.
D) This is another way of making science more reproducible.
E) Scientists need to exchange their ideas with other disciplines and cultures so that all groups are in consensus with the course of future research.
47) Since these organisms are protists, which of these characteristics could the students assume to be true?
A) The organisms are photosynthetic.
B) All of them are marine.
C) They are single-celled.
D) They lack membrane-bound organelles.
E) Each has a single circular molecule of DNA.
48) The students decide that for one of their experiments, they want to see whether the organisms can photosynthesize. Which of the following is the best hypothesis?
A) If the Dinobryon can live > 5 days without added food, they must be able to photosynthesize.
B) If the Dinobryon can live without exposure to light for > 5 days, they must be able to photosynthesize.
C) If the Dinobryon photosynthesize, they must need no other minerals or nutrients and will be able to live in distilled water and light alone.
D) If the Dinobryon are kept in the dark, one-half will be expected to die in 5 days.
E) If the Dinobryon are able to photosynthesize, the students should be able to extract photosynthetic pigments.
49) For their second experiment, the students want to know whether the Dinobryon have to live in colonies or can be free living. How might they proceed?
A) Observe each day to see whether new organisms are ever reproduced as single cells.
B) Observe whether only specialized cells are able to divide to produce new colonies.
C) Divide a sample into single cells and measure the length of time they remain this way.
D) Divide a sample into single cells and observe them.
E) Divide a sample into single cells and see whether they come back together.
50) The students plan to gather data from the project. Which of the following would be the best way to present what they gather from experimental groups as opposed to controls?
A) qualitatively, noting color, size, and so on
B) measuring the number of new colonies formed during every 12-hour period
C) counting the number of new colonies after a week
D) measuring the size of each new colony in millimeters (mm) of length
E) measuring the dry weight of all new colonies in gram
53) Which theme(s) is/are illustrated when a group of students is trying to establish which phase of cell division in root tips happens most quickly?
All the organisms on your campus make up
A) an ecosystem.
B) a community.
C) a population.
D) an experimental group.
E) a taxonomic domain.
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
A) carbon, sodium, hydrogen, nitrogen
B) carbon, oxygen, phosphorus, hydrogen
C) oxygen, hydrogen, calcium, nitrogen
D) carbon, hydrogen, nitrogen, oxygen
E) carbon, oxygen, nitrogen, calcium
Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
Which of the following statements is false?
A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter.
B) Some trace elements are very abundant on Earth.
C) Virtually all organisms require the same elements in the same quantities.
D) Iron is an example of an element needed by all organisms.
E) Other than some trace elements, animals are mostly made up of the same elements as plants, in similar proportions.
What factors are most important in determining which elements are most common in living matter?
A) the relative abundances of the elements in Earth's crust and atmosphere
B) the emergent properties of the simple compounds made from these elements
C) the reactivity of the elements with water
D) the chemical stability of the elements
E) both the relative abundances of the elements and the emergent properties of the compounds made from these elements
The precise weight of a mole of some pure elements like silicon (Si) can vary slightly from the standard atomic mass, or even from sample to sample. Why?
A) The element may undergo radioactive decay.
B) The element may react with itself and gain or lose subatomic particles.
C) The atoms of the element form chemical bonds with each other, and that changes the weight of the element.
D) The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample.
E) The amount of energy absorbed by the element affects the mass of its electrons, and thus the atomic mass can vary slightly.
In the term trace element, the modifier trace means that
A) the element is required in very small amounts.
B) the element can be used as a label to trace atoms through an organism's metabolism.
C) the element is very rare on Earth.
D) the element enhances health but is not essential for the organism's long-term survival.
E) the element passes rapidly through the organism.
Why is each element unique and different from other elements in chemical properties?
A) Each element has a unique atomic mass.
B) Each element has a unique atomic weight.
C) Each element has a unique number of protons in its nucleus.
D) Each element has a unique number of neutrons in its nucleus.
E) Each element has different radioactive properties.
Knowing just the atomic mass of an element allows inferences about which of the following?
A) the chemical properties of the element
B) the number of protons in the element
C) the number of neutrons in the element
D) the number of protons plus neutrons in the element
E) both the number of protons and the chemical properties of the element
In what way are elements in the same column of the periodic table the same?
A) They have the same number of protons.
B) They have the same number of neutrons.
C) They have the same number of electrons.
D) They have the same number of electrons in their valence shell.E) They have the same number of electron shells.
Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom?
A) exactly 8 grams
B) exactly 8 daltons
C) approximately 16 grams
D) approximately 16 daltons
E) 24 amu (atomic mass units)
The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14.
B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7.
C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams.
D) The nitrogen atom has a mass number of 7 and an atomic number of 14.
E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.
Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following can be true?
A) Molybdenum atoms can have between 50 and 58 neutrons.
B) The isotopes of molybdenum have different electron configurations.
C) The isotopes of molybdenum can have between 50 and 58 protons.
D) The isotopes of molybdenum have between 50 and 58 neutrons and have different electron configurations.
E) The isotopes of molybdenum have between 50 and 58 protons and have different electron configurations.
Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?
A) The atomic mass does not include the mass of electrons.
B) Some carbon atoms in nature have an extra proton.
C) Some carbon atoms in nature have more neutrons.
D) Some carbon atoms in nature have a different valence electron distribution.
E) Some carbon atoms in nature have undergone radioactive decay.
Which of the following best describes the relationship between the atoms described below?
Atom 1 Atom 2
A) They are isomers.
B) They are polymers.
C) They are isotopes.
D) They contain 1 and 3 protons, respectively.
E) They each contain 1 neutron.
A covalent chemical bond is one in which
A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged.
B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms.
C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.
D) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom.
E) an electron occupies a hybrid orbital located between the nuclei of two atoms.
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
A) Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
B) The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge.
C) Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge.
D) The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge.
E) There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom.
A covalent bond is likely to be polar when
A) one of the atoms sharing electrons is much more electronegative than the other atom.
B) the two atoms sharing electrons are equally electronegative.
C) oxygen is one of the two atoms sharing electrons.
D) one of the atoms has absorbed more energy than the other atom.
E) the two atoms sharing electrons are different elements.
One difference between carbon-12 ( ) is that carbon-14 ( ) has
A) two more protons than carbon-12.
B) two more electrons than carbon-12.
C) two more neutrons than carbon-12.
D) two more protons and two more neutrons than carbon-12.
E) two more electrons and two more neutrons than carbon-12.
An atom has 6 electrons in its outer shell. How many unpaired electrons does it have?
E) 2 or 4
The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
A) an electron may move to an electron shell farther away from the nucleus.
B) an electron may move to an electron shell closer to the nucleus.
C) the atom may become a radioactive isotope.
D) the atom would become a positively charged ion, or cation, and become a radioactive isotope.
E) the atom would become a negatively charged ion, or anion.
The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?
A) It has 8 electrons in its outer electron shell.
B) It is inert.
C) It has an atomic mass of 10 daltons.
D) It has 8 electrons in its outer electron shell and it is inert.
E) It has 8 electrons in its outer electron shell, it is inert, and it has an atomic mass of 10 daltons.
From its atomic number of 15, it is possible to predict that the phosphorus atom has
A) 15 neutrons.
B) 15 protons.
C) 15 electrons.
D) 8 electrons in its outermost electron shell.
E) 15 protons and 15 electrons.
Atoms whose outer electron shells contain 8 electrons tend to
A) form ions in aqueous solutions.
B) form hydrogen bonds in aqueous solutions.
C) be stable and chemically nonreactive, or inert.
D) be gaseous at room temperature.
E) be both chemically inert and gaseous at room temperature.
The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (12/6 C )?
A) 7N nitrogen
B) 9F flourine
C) 10Ne neon
D) 12Mg magnesium
E) 14Si silicon
Two atoms appear to have the same mass number. These atoms
A) must have the same atomic number.
B) must have the same number of electrons.
C) must have the same chemical properties.
D) must have the same number of protons + neutrons.
E) must have the same atomic number, the same number of protons + neutrons, the same number of electrons, and the same chemical properties.
Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?
What is the maximum number of electrons in a single 2 p orbital of an atom?
The organic molecules in living organisms have a measurably lower ratio of carbon-13/carbon-12, two stable isotopes of carbon that comprise approximately 1.1% and 98.9% of atmospheric carbon, respectively. What is a reasonable explanation for this phenomenon?
A) Photosynthesis preferentially uses carbon dioxide molecules with carbon-12, and the lower carbon-13/carbon-12 ratio propagates through the food chain.
B) Carbon dioxide molecules with carbon-13 stay in the upper atmosphere and are less available to terrestrial plants and algae.
C) Carbon-13 has a different valence electron configuration and is therefore less chemically reactive than carbon-12.
D) Oxygen atoms preferentially react with carbon-13, thereby enriching the atmosphere with carbon dioxide molecules containing carbon-13 atoms.
E) Carbon dioxide molecules containing carbon-13 are heavier and sink into the ocean depths, making them less available to living organisms.
Where is the 5’ carbon?
Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton and emits radiation in the form of an electron. What is the product of such radioactive decay of phosphorus-32?
B) a positively charged phosphorus-31 ion
C) a negatively charged phosphorus-32 ion
D) sulfur-32 (atomic number 16)
E) the conversion of the phosphorus-32 atom into pure energy
An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
A) It would form ions with a +1 charge.
B) It would form ions with a +2 charge.
C) It would form ions with a -1 charge.
D) It would form ions with a -2 charge.
E) It would form two covalent bonds with other atoms.
If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal?
A) a surface coated with a thin film of water
B) a surface made with carbon and hydrogen atoms covalently bonded together
C) a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together
D) a surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together
E) a surface made with silicon and oxygen atoms covalently bonded together
What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
When two atoms are equally electronegative, they will interact to form
A) hydrogen bonds.
B) van der Waals interactions.
C) polar covalent bonds.
D) nonpolar covalent bonds.
E) ionic bonds.
What results from an unequal sharing of electrons between atoms?
A) a nonpolar covalent bond
B) a polar covalent bond
C) an ionic bond
D) a hydrogen bond
E) a hydrophobic interaction
Which of the following explains most specifically the attraction of water molecules to one another?
A) nonpolar covalent bond
B) polar covalent bond
C) ionic bond
D) hydrogen bond
E) hydrophobic interaction
Which of the following molecules contains the most polar covalent bond?
In comparing covalent bonds and ionic bonds, which of the following would you expect?
A) An atom can form covalent bonds with multiple partner atoms, but only a single ionic bond with a single partner atom.
B) Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons.
C) Both involve electrical attraction between the electrons of one atom and the nucleus of the other atom.
D) Ionic interactions remain when covalent bonds are broken in water. Ionic bonds are much stronger than covalent bonds.
Which bond or interaction would be difficult to disrupt when compounds are put into water?
A) covalent bond
B) hydrogen bond
C) van der Waals interaction
D) ionic bond
E) either covalent bonds or ionic bonds
What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)?
A) covalent bonding
B) polar covalent bonding
C) ionic bonding
D) hydrogen bonding
E) van der Waals interactions
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds.
D) ionic bonds.
E) van der Waals interactions.
Which type of bond must be broken for water to vaporize?
A) ionic bonds
B) both hydrogen bonds and ionic bonds
C) polar covalent bonds
D) hydrogen bonds
E) both polar covalent bonds and hydrogen bonds
A carbon atom is most likely to form what kind of bond(s) with other atoms?
D) covalent bonds and hydrogen bonds
E) ionic bonds, covalent bonds, and hydrogen bonds
Which bonds are created during the formation of the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) phosphodiester bonds
E) peptide bonds, hydrogen bonds, and disulfide bonds
What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds
D) hydrophobic interactions
E) hydrogen bonds between the R groups
What is the difference between covalent bonds and ionic bonds?
A) Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds.
B) Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.
C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
D) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms.
E) Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms.
In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl. What is the cation of NH4Cl?
A) N, with a charge of +1
B) NH, with a charge of +1
C) H3, with a charge of +1
D) NH4, with a charge of +1
E) NH4, with a charge of +4
The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4?
Van der Waals interactions result when
A) hybrid orbitals overlap.
B) electrons are not symmetrically distributed in a molecule.
C) molecules held by ionic bonds react with water.
D) two polar covalent bonds react.
E) a hydrogen atom loses an electron.
Which of the following would be regarded as compounds?
A) H2O, O2, and CH4
B) H2O and O2
C) O2 and CH4
D) CH4 and O2, but not H2O
E) H2O and CH4, but not O2
What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
Which of the following is true for this reaction?
3 H2 + N2 ↔ 2 NH3
A) The reaction is nonreversible.
B) Hydrogen and nitrogen are the reactants of the reverse reaction.
C) Hydrogen and nitrogen are the products of the forward reaction.
D) Ammonia is being formed and decomposed.
E) Hydrogen and nitrogen are being decomposed.
Which of the following correctly describes chemical equilibrium?
A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.
B) Concentrations of products are higher than the concentrations of the reactants.
C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products.
D) Reactions stop only when all reactants have been converted to products.
E) There are equal concentrations of reactants and products, and the reactions have stopped.
Which of the following correctly describes any reaction that has reached chemical equilibrium?
A) The concentration of the reactants equals the concentration of the products.
B) The rate of the forward reaction is equal to the rate of the reverse reaction.
C) All of the reactants have been converted to the products of the reaction.
D) All of the products have been converted to the reactants of the reaction.
E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products.
Which of these systems is least likely to be at chemical equilibrium?
A) a test tube of living cells
B) a test tube of organic molecules, kept in the freezer
C) a test tube of dry organic molecules, kept at room temperature
D) a test tube of organic molecules dissolved in water, kept at room temperature
E) a test tube of dead cells in water, kept at room temperature
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
A) a covalent bond
B) a hydrogen bond
C) an ionic bond
D) a hydrophilic bond
E) a van der Waals interaction
The partial negative charge in a molecule of water occurs because
A) the oxygen atom acquires an additional electron.
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.
Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S
A) will ionize more readily.
B) will have greater cohesion to other molecules of H2S.
C) will have a greater tendency to form hydrogen bonds with each other.
D) will have a higher capacity to absorb heat for the same change in temperature.
E) will not form hydrogen bonds with each other.
Water molecules are able to form hydrogen bonds with
A) compounds that have polar covalent bonds.
C) oxygen gas (O2) molecules.
D) chloride ions.
E) any compound that is not soluble in water.
Which of the following effects is produced by the high surface tension of water?
A) Lakes don't freeze solid in winter, despite low temperatures.
B) A water strider can walk across the surface of a small pond.
C) Organisms resist temperature changes, although they give off heat due to chemical reactions.
D) Evaporation of sweat from the skin helps to keep people from overheating.
E) Water flows upward from the roots to the leaves in plants.
Which of the following takes place as an ice cube cools a drink?
A) Molecular collisions in the drink increase.
B) Kinetic energy in the drink decreases.
C) A calorie of heat energy is transferred from the ice to the water of the drink.
D) The specific heat of the water in the drink decreases.
E) Evaporation of the water in the drink increases.
A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie?
A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C
B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C
C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F
D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C
E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C
The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?
Liquid water's high specific heat is mainly a consequence of the
A) small size of the water molecules.
B) high specific heat of oxygen and hydrogen atoms.
C) absorption and release of heat when hydrogen bonds break and form.
D) fact that water is a poor heat conductor.
E) higher density of liquid water than solid water (ice).
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
A) the change in density when it condenses to form a liquid or solid
B) reactions with other atmospheric compounds
C) the release of heat by the formation of hydrogen bonds
D) the release of heat by the breaking of hydrogen bonds
E) the high surface tension of water
Why does evaporation of water from a surface cause cooling of the surface?
A) The breaking of bonds between water molecules absorbs heat.
B) The water molecules with the most heat energy evaporate more readily.
C) The solute molecules left behind absorb heat.
D) Water molecules absorb heat from the surface in order to acquire enough energy to evaporate.
E) The expansion of water vapor extracts heat from the surface.
Why does ice float in liquid water?
A) The high surface tension of liquid water keeps the ice on top.
B) The ionic bonds between the molecules in ice prevent the ice from sinking.
C) Ice always has air bubbles that keep it afloat.
D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
E) The crystalline lattice of ice causes it to be denser than liquid water.
Hydrophobic substances such as vegetable oil are
A) nonpolar substances that repel water molecules.
B) nonpolar substances that have an attraction for water molecules.
C) polar substances that repel water molecules.
D) polar substances that have an affinity for water.
E) charged molecules that hydrogen-bond with water molecules.
One mole (mol) of glucose (molecular mass = 180 daltons) is
A) 180 × 10^23 molecules of glucose.
B) 1 kg of glucose dissolved in 1 L of solution.
C) the largest amount of glucose that can be dissolved in 1 L of solution.
D) 180 kilograms of glucose.
E) both 180 grams of glucose and 6.02 × 10^23 molecules of glucose.
How many molecules of glucose (C6H12O6 molecular mass = 180 daltons) would be present in 90 grams of glucose?
A) 90 × 10^23
B) (6.02/180) × 10^23
C) (6.02/90) × 10^23
D) (90 x 6.02) × 10^23
E) (90/180) × 6.02 × 10^23
How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution?
A) 1 × 10^6
B) 14 × 6.02 × 10^23
C) 92 × 6.02 × 10^23
D) 6.02 × 10^26
E) 6.02 × 10^23
You have a freshly prepared 0.1 M solution of glucose in water. Each liter of this solution contains how many glucose molecules?
A) 6.02 × 10^23
B) 3.01 × 10^23
C) 6.02 × 10^24
D) 12.04 × 10^23
E) 6.02 × 10^22
When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
A) 1 L of 0.5 M NaCl
B) 1 L of 0.5 M glucose
C) 1 L of 1.0 M NaCl
D) 1 L of 1.0 M glucose
E) 1 L of 1.0 M NaCl and 1 L of 1.0 M glucose will contain equal numbers of solute particles.
The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to make a 1 M solution of glucose?
A) Dissolve 1 g of glucose in 1 L of water.
B) Dissolve 180 g of glucose in 1 L of water.
C) Dissolve 180 g of glucose in 180 g of water.
D) Dissolve 180 milligrams (mg) of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the solution is 1 L.
The molar mass of glucose (C6H12O6) is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose?
A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L.
B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
D) Dissolve 0.5 g of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.5 L of water.
The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? (Hint: What is the mass of 1 liter of pure water?)
A) 55.6 M
B) 18 M
C) 37 M
D) 0.66 M
E) 1.0 M
A strong acid like HCl
A) ionizes completely in an aqueous solution.
B) increases the pH when added to an aqueous solution.
C) reacts with strong bases to create a buffered solution.
D) is a strong buffer at low pH.
E) both ionizes completely in aqueous solutions and is a strong buffer at low pH.
Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
A) It is a strong acid that ionizes completely in water.
B) It is a strong base that ionizes completely in water.
C) It is a weak acid.
D) It is a weak base.
E) It is neither an acid nor a base.
A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?
A) acidic: will accept H+ from both strong and weak acids
B) basic: will accept H+ from both strong and weak acids
C) acidic: will give H+ to weak acids, but accept H+ from strong acids
D) basic: will give H+ to weak acids, but accept H+ from weak acids
E) acidic: will give H+ to both strong and weak acids
What is an acid?
A molecule that releases H+ and leads to a lower pH
A solution contains 0.0000001(10-7) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution?
A) acidic: H+ acceptor
B) basic: H+ acceptor
C) acidic: H+ donor
D) basic: H+ donor
What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M?
A) pH 2
B) pH 4
C) pH 10
D) pH 12
E) pH 14
What is the pH of a 1 millimolar NaOH solution?
A) pH 3
B) pH 8
C) pH 9
D) pH 10
E) pH 11
Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
A) gastric juice at pH 2
B) vinegar at pH 3
C) tomato juice at pH 4
D) black coffee at pH 5
E) household bleach at pH 12
What is the hydrogen ion [H+] concentration of a solution of pH 8?
A) 8 M
B) 8 x 10-6 M
C) 0.01 M
D) 10-8 M
E) 10-6 M
If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9.
B) concentration of H+ has increased tenfold (10X) compared to what it was at pH 9.
C) concentration of OH- has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH- has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H+ has increased tenfold (10X) and the concentration of OH- has decreased to one-tenth (1/10) what they were at pH 9.
If the pH of a solution is increased from pH 5 to pH 7, it means that the
A) concentration of H+ is twice (2X) what it was at pH 5.
B) concentration of H+ is one-half (1/2) what it was at pH 5.
C) concentration of OH- is 100 times greater than what it was at pH 5.
D) concentration of OH- is one-hundredth (0.01X) what it was at pH 5.
E) concentration of H+ is 100 times greater and the concentration of OH- is one-hundredth what they were at pH 5.
One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH 6?
A) 4 times more
B) 16 times more
C) 40,000 times more
D) 10,000 times more
E) 100,000 times more
One liter of a solution of pH 9 has how many more hydroxyl ions (OH-) than 1 L of a solution of pH 4?
A) 5 times more
B) 32 times more
C) 50,000 times more
D) 10,000 times more
E) 100,000 times more
Which of the following statements is true about buffer solutions?
A) They maintain a constant pH when bases are added to them but not when acids are added to them.
B) They maintain a constant pH when acids are added to them but not when bases are added to them.
C) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them.
D) They maintain a relatively constant pH when either acids or bases are added to them.
E) They are found only in living systems and biological fluids.
Buffers are substances that help resist shifts in pH by
A) releasing H+ to a solution when acids are added.
B) donating H+ to a solution when bases are added.
C) releasing OH- to a solution when bases are added.
D) accepting H+ from a solution when acids are added.
E) both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus,
H2CO3 ↔ HCO3- + H+
If the pH of the blood drops, one would expect
A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.
B) the concentration of hydroxide ion (OH-) to increase.
C) the concentration of bicarbonate ion (HCO3-) to increase.
D) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3.
E) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3.
One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3- and a hydrogen ion (H+). Thus,
H2CO3 ↔ HCO3- + H+
If the pH of the blood increases, one would expect
A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.
B) an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3-.
C) a decrease in the concentration of HCO3- and an increase in the concentration of H+.
D) an increase in the concentration of HCO3- and a decrease in the concentration of OH-.
E) a decrease in the concentration of HCO3- and an increase in the concentration of both H2CO3 and H+.
If glucose is available in the environment of E. coli, the cell responds with a very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect to be a measurable effect?
A) decreased concentration of the lac enzymes
B) increased concentration of the trp enzymes
C) decreased binding of the RNA polymerase to sugar metabolism-related promoters
D) decreased concentration of alternative sugars in the cell
E) increased concentrations of sugars such as arabinose in the cell
Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake?
A) 1 × 10-10 mol of hydroxyl ion per liter of lake water
B) 1 × 10-4 mol of hydroxyl ion per liter of lake water
C) 10.0 M with regard to hydroxyl ion concentration
D) 4.0 M with regard to hydroxyl ion concentration
E) 1 × 10-4 mol of hydroxyl ion per liter of lake water and 4.0 M with regard to hydrogen ion concentration
Research indicates that acid precipitation can damage living organisms by
A) buffering aquatic systems such as lakes and streams.
B) decreasing the H+ concentration of lakes and streams.
C) increasing the OH- concentration of lakes and streams.
D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth.
E) both decreasing the H+ concentration of lakes and streams and increasing the OH- concentration of lakes and streams.
Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that
A) solution Y has no free hydrogen ions (H+).
B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y.
C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X.
D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y.
E) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of hydrogen ions in solution Y.
What is a solute?
The liquid, solid, or gas dissolved to form a solution
If a solution has a pH of 7, this means that
A) there are no H+ ions in the water.
B) this is a solution of pure water.
C) the concentration of H+ ions in the water equals the concentration of OH- ions in the water.
D) this is a solution of pure water, and the concentration of H+ ions in the water is 10-7 M.
E) this is a solution of pure water, and the concentration of H+ ions equals the concentration of OH- ions in the water.
Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2 into the bloodstream. What will be the effect on pH of blood as that blood first comes in contact with respiring cells?
A) Blood pH will decrease slightly.
B) Blood pH will increase slightly.
C) Blood pH will remain unchanged.
D) Blood pH will first increase, then decrease as CO2 combines with hemoglobin.
E) Blood pH will first decrease, then increase sharply as CO2 combines with hemoglobin.
A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing?
A) The concentration of Na+ ion rises.
B) The concentration of Cl- ion will be 0.1 M.
C) The concentration of undissociated H2O molecules remains unchanged.
D) The pH of the beaker's contents will be neutral.
E) The pH of the beaker's contents falls.
Equal volumes (5 mL) of vinegar from a freshly opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH?
A) 100 mL of pure water
B) 100 mL of freshly brewed coffee
C) 100 mL of household cleanser containing 0.5 M ammonia
D) 100 mL of freshly squeezed orange juice
E) 100 mL of tomato juice
Increased atmospheric CO2 concentrations might have what effect on seawater?
A) Seawater will become more acidic, and bicarbonate concentrations will decrease.
B) Seawater will become more alkaline, and carbonate concentrations will decrease.
C) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate.
D) Seawater will become more acidic, and carbonate concentrations will decrease.
E) Seawater will become more acidic, and carbonate concentrations will increase.
How would acidification of seawater affect marine organisms?
A) Acidification would increase dissolved carbonate concentrations and promote faster growth of corals and shell-building animals.
B) Acidification would decrease dissolved carbonate concentrations and promote faster growth of corals and shell-building animals.
C) Acidification would increase dissolved carbonate concentrations and hinder growth of corals and shell-building animals.
D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals.
E) Acidification would increase dissolved bicarbonate concentrations, and cause increased calcification of corals and shellfish.
One idea to mitigate the effects of burning fossil fuels on atmospheric CO2 concentrations is to pipe liquid CO2 into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO2 is heavier than water. What potential effects might result from implementing such a scheme?
A) increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the deep water
B) increased carbonate concentrations in the deep waters
C) reduced growth of corals from a change in the carbonate—bicarbonate equilibrium
D) no effect because carbon dioxide is not soluble in water
E) both increased acidity of the deep waters and changes in the growth of bottom-dwelling organisms with calcium carbonate shells
If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that
A) the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
B) the concentration of H+ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm.
C) the concentration of H+ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix.
D) the mitochondrial matrix is more acidic than the cytoplasm.
E) the concentration of H+ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix.
The element present in all organic molecules is
The complexity and variety of organic molecules is due to
A) the chemical versatility of carbon atoms.
B) the variety of rare elements in organic molecules.
C) the fact that they can be synthesized only in living organisms.
D) their interaction with water.
E) their tremendously large sizes.
The experimental approach taken in current biological investigations presumes that
A) simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms.
B) a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods.
C) although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods.
D) living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products.
E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.
Differences among organisms are caused by
A) large differences in elemental composition from organism to organism.
B) differences in the types and relative amounts of organic molecules synthesized by each organism.
C) differences in the elements that bond with carbon in each organism.
D) differences in the sizes of the organic molecules in each organism.
E) differences in inorganic compounds present in each organism.
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
A) The energy content of an organism is constant.
B) The organism ultimately must obtain all of the necessary energy for life from its environment.
C) The entropy of an organism decreases with time as the organism grows in complexity.
D) Organisms grow by converting energy into organic matter.
E) Life does not obey the first law of thermodynamics.
An organism is discovered that thrives both in the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism
A) must use a molecule other than oxygen to accept electrons from the electron transport chain.
B) is a normal eukaryotic organism.
C) is photosynthetic.
D) is an anaerobic organism.
E) is a facultative anaerobe.
What is organization?
Separation between internal
and external environment
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A) A gene from an organism can theoretically be expressed by any other organism.
B) All organisms have experienced convergent evolution.
C) DNA was the first genetic material.
D) The same codons in different organisms translate into the different amino acids.
E) Different organisms have different numbers of different types of amino acids.
Which of the following people was the first to synthesize an organic compound, urea, from inorganic starting materials?
A) Stanley Miller
B) Jakob Berzelius
C) Friedrich Wohler
D) Hermann Kolbe
E) August Kekulé
Stanley Miller's 1953 experiments proved that
A) life arose on Earth from simple inorganic molecules.
B) organic molecules can be synthesized abiotically under conditions that may have existed on early Earth.
C) life arose on Earth from simple organic molecules, with energy from lightning and volcanoes.
D) the conditions on early Earth were conducive to the origin of life.E) the conditions on early Earth were conducive to the abiotic synthesis of organic molecules
Hermann Kolbe's synthesis of an organic compound, acetic acid, from inorganic substances that had been prepared directly from pure elements was a significant milestone for what reason?
A) It solved an industrial shortage of acetic acid.
B) It proved that organic compounds could be synthesized from inorganic compounds.
C) It disproved the concept of vitalism.
D) It showed that life originated from simple inorganic chemicals.
E) It proved that organic compounds could be synthesized from inorganic compounds and disproved the concept of vitalism.
Stanley Miller's 1953 experiments assumed that early Earth's atmosphere contained
A) hydrogen cyanide, formaldehyde, hydrogen gas, and water vapor.
B) ammonia, methane, hydrogen gas, and water vapor.
C) ammonia, methane, oxygen gas, and water vapor.
D) amino acids, methane, hydrogen cyanide, and water vapor.
E) methane, formaldehyde, ammonia, and carbon dioxide.
When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced?
A) mostly amino acids
B) only simple organic compounds such as formaldehyde and cyanide
C) mostly hydrocarbons
D) only simple inorganic compounds
E) both simple organic compounds and more complex organic compounds such as amino acids and hydrocarbons
How many electron pairs does carbon share in order to complete its valence shell?
Which of the following statements best describes the carbon atoms present in a seed-eating bird?
A) They were incorporated into organic molecules by plants.
B) They were processed into sugars through photosynthesis.
C) They are ultimately derived from carbon dioxide.
D) They were incorporated into organic molecules by plants, and they are ultimately derived from carbon dioxide.
E) They were incorporated into organic molecules by plants, they were processed into sugars through photosynthesis, and they are ultimately derived from carbon dioxide.
Which of the following statements best describes the carbon atoms present in a seed-eating bird?
A) Inorganic carbon atoms in the seeds were incorporated into organic molecules by the bird.
B) The carbon atoms ultimately came from the soil.
C) The carbon atoms are ultimately derived from coal.
D) The carbon atoms ultimately came from carbon dioxide incorporated into sugars through photosynthesis.
E) The carbon atoms ultimately came from simple organic compounds that formed abiotically from inorganic carbon, hydrogen, oxygen, and nitrogen atoms.
Why are hydrocarbons insoluble in water?
A) The majority of their bonds are polar covalent carbon-to-hydrogen linkages.
B) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
C) They are hydrophilic.
D) They exhibit considerable molecular complexity and diversity.
E) They are lighter than water.
How many structural isomers are possible for a substance having the molecular formula C4H10?
Which of the following statements correctly describes cis-trans isomers?
A) They have variations in arrangement around a double bond.
B) They have an asymmetric carbon that makes them mirror images.
C) They have the same chemical properties.
D) They have different molecular formulas.
E) Their atoms and bonds are arranged in different sequences.
Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
A) have identical chemical formulas but differ in the branching of their carbon skeletons.
B) are mirror images of one another.
C) exist in either linear chain or ring forms.
D) differ in the location of their double bonds.
E) differ in the arrangement of atoms around their double bonds.
What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?
A) the presence or absence of bonds with oxygen atoms
B) the presence or absence of double bonds between the carbon atom and other atoms
C) the polarity of the covalent bonds between carbon and other atoms
D) the presence or absence of bonds with nitrogen atoms
E) the solvent that the organic molecule is dissolved in
Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will
A) be more flexible in structure.
B) be more constrained in structure.
C) be more polar.
D) have more hydrogen atoms.
E) have fewer structurally distinct isomers.
Organic molecules with only hydrogens and five carbon atoms can have different structures in all of the following ways except
A) by branching of the carbon skeleton.
B) by varying the number of double bonds between carbon atoms.
C) by varying the position of double bonds between carbon atoms.
D) by forming a ring.
E) by forming enantiomers.
A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
A) It lacks an asymmetric carbon, and it is probably a fat or lipid.
B) It should dissolve in water.
C) It should dissolve in a nonpolar solvent.
D) It won't form hydrogen bonds with water.
E) It is hydrophobic.
Which of the following is a false statement concerning amino groups?
A) They are basic in pH.
B) They are found in amino acids.
C) They contain nitrogen.
D) They are nonpolar.
E) They are components of urea.
Which two functional groups are always found in amino acids?
A) ketone and methyl
B) carbonyl and amino
C) carboxyl and amino
D) amino and sulfhydryl
E) hydroxyl and carboxyl
Amino acids are acids because they always possess which functional group?
A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it
A) would function only as an acid because of the carboxyl group.
B) would function only as a base because of the amino group.
C) would function as neither an acid nor a base.
D) would function as both an acid and a base.
E) is impossible to determine how it would function.
Which functional groups can act as acids?
A) amino and sulfhydryl
B) carbonyl and carboxyl
C) carboxyl and phosphate
D) hydroxyl and aldehyde
E) ketone and amino
Testosterone and estradiol are
A) soluble in water.
B) structural isomers of each other.
E) enantiomers of each other.
Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?
A) Testosterone and estradiol are structural isomers but have the same molecular formula.
B) Testosterone and estradiol are cis-trans isomers but have the same molecular formula.
C) Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
D) Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, while the other has three rings.
E) Testosterone and estradiol are enantiomers of the same organic molecule.
The two molecules shown in the figure above are best described as
A) optical isomers.
C) structural isomers.
D) cis-trans isomers.
E) chain length isomers.
What is an isomer?
Two molecules with the
same molecular formula,
but different structures
Which of these molecules is not formed by dehydration reactions?
A) fatty acids
Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?
D) nucleic acids
E) lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers
Which of the following is not a polymer?
What is the chemical reaction mechanism by which cells make polymers from monomers?
A) phosphodiester linkages
C) dehydration reactions
D) ionic bonding of monomers
E) the formation of disulfide bridges between monomers
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?
D) glycogen and chitin only
E) glycogen, cellulose, and chitin
Which of the following is true of both starch and cellulose?
A) They are both polymers of glucose.
B) They are cis-trans isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in plants.
E) They are both structural components of the plant cell wall.
Humans can digest starch but not cellulose because
A) the monomer of starch is glucose, while the monomer of cellulose is galactose.
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
D) humans harbor starch-digesting bacteria in the digestive tract.
E) the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group.
Which of the following statements concerning saturated fats is not true?
A) They are more common in animals than in plants.
B) They have multiple double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than unsaturated fats having the same number of carbon atoms.
E) They are one of several factors that contribute to atherosclerosis.
A molecule with the formula C18H36O2 is probably a
C) fatty acid.
D) nucleic acid.
Which of the following statements is true for the class of biological molecules known as lipids?
A) They are insoluble in water.
B) They are made from glycerol, fatty acids, and phosphate.
C) They contain less energy than proteins and carbohydrates.
D) They are made by dehydration reactions.
E) They contain nitrogen.
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
A) The hydrogenated vegetable oil has a lower melting point.
B) The hydrogenated vegetable oil stays solid at room temperature.
C) The hydrogenated vegetable oil has more "kinks" in the fatty acid chains.
D) The hydrogenated vegetable oil has fewer trans fatty acids.
E) The hydrogenated vegetable oil is less likely to clog arteries.
Which of the following is true regarding saturated fatty acids?
A) They are the predominant fatty acid in corn oil.
B) They have double bonds between carbon atoms of the fatty acids.
C) They are the principal molecules in lard and butter.
D) They are usually liquid at room temperature.
E) They are usually produced by plants.
Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
A) The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
B) Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in membranes.
C) Unsaturated fatty acids are more polar than saturated fatty acids.
D) The double bonds block interaction among the hydrophilic head groups of the lipids.
E) The double bonds result in shorter fatty acid tails and thinner membranes.
Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?
A) a steroid
D) an enzyme
E) a contractile protein
Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
A) creating cis double bonds to the fatty acids
B) adding hydrogens to the fatty acids
C) creating trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
E) adding cis double bonds and trans double bonds to the fatty acids
Why are human sex hormones considered to be lipids?
A) They are essential components of cell membranes.
B) They are not soluble in water.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
E) They contribute to atherosclerosis.
All of the following contain amino acids except
The bonding of two amino acid molecules to form a larger molecule requires
A) the release of a water molecule.
B) the release of a carbon dioxide molecule.
C) the addition of a nitrogen atom.
D) the addition of a water molecule.
E) the release of a nitrous oxide molecule.
What is a molecule?
2 or more atoms
Name this molecule
What can you tell me about this molecule?
Fatty acid (lipid)
Man-made (trans fat)
What can you tell me about this molecule?
Fatty acid (lipid)
What is this molecule?
There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to a carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different structural and optical isomers
E) different asymmetric carbons
The bonding of two amino acid molecules to form a larger molecule requires which of the following?
A) removal of a water molecule
B) addition of a water molecule
C) formation of a glycosidic bond
D) formation of a hydrogen bond
E) both removal of a water molecule and formation of a hydrogen bond
Polysaccharides, triacylglycerides, and proteins are similar in that they
A) are synthesized from monomers by the process of hydrolysis.
B) are synthesized from subunits by dehydration reactions.
C) are synthesized as a result of peptide bond formation between monomers.
D) are decomposed into their subunits by dehydration reactions.
E) all contain nitrogen in their monomer building blocks.
Dehydration reactions are used in forming which of the following compounds?
D) triacylglycerides and proteins only
E) triacylglycerides, polysaccharides, and proteins
Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
A) hydrophobic interactions
B) disulfide bonds
C) ionic bonds
D) hydrogen bonds
E) peptide bonds
What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?
A) ionic bond
B) hydrophobic interaction
C) van der Waals interaction
D) disulfide bond
E) hydrogen bond
Which level of protein structure do the α helix and the β pleated sheet represent?
E) primary, secondary, tertiary, and quaternary
The tertiary structure of a protein is the
A) bonding together of several polypeptide chains by weak bonds.
B) order in which amino acids are joined in a polypeptide chain.
C) unique three-dimensional shape of the fully folded polypeptide.
D) organization of a polypeptide chain into an α helix or β pleated sheet.
E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.
What is a
A polymer formed from amino acids
Folds to form a protein
At which level of protein structure are interactions between the side chains (R groups) most important?
E) all of the above
The R group or side chain of the amino acid serine is –CH2–OH. The R group or side chain of the amino acid leucine is –CH2–CH–(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Both serine and leucine would be in the interior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
E) Both serine and leucine would be in the interior and on the exterior of the globular protein.
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
A) Alzheimer's only
B) Parkinson's only
C) diabetes mellitus only
D) Alzheimer's and Parkinson's only
E) Alzheimer's, Parkinson's, and diabetes mellitus
Changing a single amino acid in a protein consisting of 325 amino acids would
A) alter the primary structure of the protein, but not its tertiary structure or function.
B) cause the tertiary structure of the protein to unfold.
C) always alter the biological activity or function of the protein.
D) always alter the primary structure of the protein and disrupt its biological activity.
E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and affect its biological activity.
Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits
A) altered primary structure.
B) altered secondary structure.
C) altered tertiary structure.
D) altered quaternary structure.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.
What methods may be used to elucidate the structures of purified proteins?
A) X-ray crystallography
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) both X-ray crystallography and NMR spectroscopy
In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains
E) anywhere in the protein, with equal probability
Which of the following techniques uses the amino acid sequences of polypeptides to predict a protein's three-dimensional structure?
A) X-ray crystallography
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) high-speed centrifugation
If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled?
B) nucleic acids
E) both proteins and nucleic acids
What is the term used for a protein molecule that assists in the proper folding of other proteins?
A) tertiary protein
C) enzyme protein
D) renaturing protein
E) denaturing protein
A protein that spans the phospholipid bilayer one or more times is
A) a transmembrane protein.
B) an integral protein.
C) a peripheral protein.
D) an integrin.
E) a glycoprotein.
Which of these are not embedded in the hydrophobic portion of the lipid bilayer at all?
A) transmembrane proteins
B) integral proteins
C) peripheral proteins
What is the difference between quaternary protein structure and protein-protein interactions?
Quaternary (4°) is used to form a protein
Protein-protein occurs between multiple fully formed proteins
DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
A) The two strands of the double helix would separate.
B) The phosphodiester bonds between deoxyribose sugars would be broken.
C) The purines would be separated from the deoxyribose sugars.
D) The pyrimidines would be separated from the deoxyribose sugars.
E) All bases would be separated from the deoxyribose sugars.
Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5' end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.
D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose.
E) The 5' end is the fifth position on one of the nitrogenous bases.
One of the primary functions of RNA molecules is to
A) transmit genetic information to offspring.
B) function in the synthesis of proteins.
C) make a copy of itself, thus ensuring genetic continuity.
D) act as a pattern or blueprint to form DNA.
E) form the genes of higher organisms.
If 14C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labeled?
D) both DNA and RNA
Which of the following descriptions best fits the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a nitrogenous base and a pentose sugar
C) a nitrogenous base, a phosphate group, and a pentose sugar
D) a phosphate group and an adenine or uracil
E) a pentose sugar and a purine or pyrimidine
Which of the following are nitrogenous bases of the pyrimidine type?
A) guanine and adenine
B) cytosine and uracil
C) thymine and guanine
D) ribose and deoxyribose
E) adenine and thymine
Which of the following are nitrogenous bases of the purine type?
A) cytosine and guanine
B) guanine and adenine
C) adenine and thymine
D) thymine and uracil
E) uracil and cytosine
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
E) impossible to tell from the information given
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
A) 120 adenine and 120 uracil molecules.
B) 120 thymine and 120 adenine molecules.
C) 120 cytosine and 120 thymine molecules.
D) 120 adenine and 120 cytosine molecules.
E) 120 guanine and 120 thymine molecules.
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar.
B) can form a double-stranded molecule.
C) is an aldehyde sugar and the sugar in RNA is a keto sugar.
D) is in the α configuration and the sugar in RNA is in the β configuration.
E) contains one less oxygen atom.
Which of the following statements best summarizes the differences between DNA and RNA?
A) DNA encodes hereditary information, whereas RNA does not.
B) The bases in DNA form base-paired duplexes, whereas the bases in RNA do not.
C) DNA nucleotides contain a different sugar than RNA nucleotides.
D) DNA contains the base uracil, whereas RNA contains the base thymine.
E) DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides.
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
What is the structural feature that allows DNA to replicate?
A) sugar-phosphate backbone
B) complementary pairing of the nitrogenous bases
C) disulfide bonding (bridging) of the two helixes
D) twisting of the molecule to form an α helix
E) three-component structure of the nucleotides
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism
A) is more closely related to humans than to frogs.
B) is more closely related to frogs than to humans.
C) evolved at about the same time as frogs, which is much earlier than primates and mammals.
D) is more closely related to humans than to rats.
E) is more closely related to frogs than to humans and also evolved at about the same time as frogs, which is much earlier than primates and mammals.
Which of the following is an example of hydrolysis?
A) the reaction of two monosaccharides, forming a disaccharide with the release of water
B) the synthesis of two amino acids, forming a peptide with the release of water
C) the reaction of a fat, forming glycerol and fatty acids with the release of water
D) the reaction of a fat, forming glycerol and fatty acids with the consumption of water
E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water
If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?
B) nucleic acids
E) both phospholipids and nucleic acids
If cells are grown in a medium containing radioactive 15N, which of these molecules will be labeled?
A) fatty acids only
B) nucleic acids only
C) proteins only
D) amylase only
E) both proteins and nucleic acids
How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?
A) DNA duplexes will unwind and separate.
B) Proteins will unfold (denature).
C) Starch will hydrolyze into monomeric sugars.
D) Proteins will hydrolyze into amino acids.
E) DNA duplexes will unwind and separate, and proteins will unfold (denature).
Which of the following is not a monomer/polymer pairing?
B) amino acid/protein
C) triglyceride/phospholipid bilayer
When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using
A) a phase-contrast light microscope.
B) a scanning electron microscope.
C) a transmission electronic microscope.
D) a confocal fluorescence microscope.
E) a super-resolution fluorescence microscope.
The advantage of light microscopy over electron microscopy is that
A) light microscopy provides for higher magnification than electron microscopy.
B) light microscopy provides for higher resolving power than electron microscopy.
C) light microscopy allows one to view dynamic processes in living cells.
D) light microscopy provides higher contrast than electron microscopy.
E) specimen preparation for light microcopy does not produce artifacts.
What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division?
A) light microscopy
B) scanning electron microscopy
C) transmission electron microscopy
D) confocal fluorescence microscopy
E) super-resolution fluorescence microscopy
A primary objective of cell fractionation is to
A) view the structure of cell membranes.
B) sort cells based on their size and weight.
C) determine the size of various organelles.
D) separate the major organelles so that their particular functions can be determined.
E) separate lipid-soluble from water-soluble molecules.
What is an enantiomer?
Isomers that are mirror images
- DNA replication occurs
- strands uncoil and separate before each strand replicates
- results in chromatids attached at a centromore
What is a buffer solution?
Solution that regulates and maintains a specific pH
- harvesting of light energy by ATP
- passing electrons to the thylakoid membrane electron transport chain
- receiving electrons from the thylakoid membrane electron transport chain
- extraction of hydrogen electrons from the splitting of water
- generation of molecular oxygen
Nitrous oxide gas molecules diffusing across a cell's plasma membrane is an example of
A) diffusion across the lipid bilayer.
B) facilitated diffusion.
C) active transport.
In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is
A) the relative solubility of the component.
B) the size and weight of the component.
C) the percentage of carbohydrates in the component.
D) the presence or absence of nucleic acids in the component.
E) the presence or absence of lipids in the component.
Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge?
A) ribosomes, nucleus, mitochondria
B) chloroplasts, ribosomes, vacuoles
C) nucleus, ribosomes, chloroplasts
D) vacuoles, ribosomes, nucleus
E) nucleus, mitochondria, ribosomes
Green fluorescent protein (GFP) can be used to fluorescently label a specific protein in cells by genetically engineering cells to synthesize the target protein fused to GFP. What is the advantage of using GFP fusions to visualize specific proteins, instead of staining cells with fluorescently labeled probes that bind to the target protein?
A) GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells.
B) GFP fusions enable higher resolution than staining with fluorescent probes.
C) GFP permits the position of the protein in the cell more precisely than fluorescent probes.
D) GFP permits visualization of protein-protein interactions; fluorescent probes do not.
E) GFP fusions are not subject to artifacts; fluorescent probes may introduce background artifacts.
What is the reason that a modern electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?
A) The focal length of the electron microscope is significantly longer.
B) Contrast is enhanced by staining with atoms of heavy metal.
C) Electron beams have much shorter wavelengths than visible light.
D) The electron microscope has a much greater ratio of image size to real size.
E) The electron microscope cannot image whole cells at one time.
All of the following are part of a prokaryotic cell except
B) a cell wall.
C) a plasma membrane.
E) an endoplasmic reticulum.
The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that
A) plant cells are capable of having a much higher surface-to-volume ratio than animal cells.
B) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells.
C) plant cells contain a large vacuole that reduces the volume of the cytoplasm.
D) animal cells are more spherical, whereas plant cells are elongated.
E) plant cells can have lower surface-to-volume ratios than animal cells because plant cells synthesize their own nutrients.
An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?
A) transporting ions against an electrochemical gradient
B) cell-cell recognition
C) maintaining fluidity of the phospholipid bilayer
D) attaching to the cytoskeleton
E) establishing the diffusion barrier to charged molecules
When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?
A) The cell will burst.
B) The cell membrane will lyse.
C) Plasmolysis will shrink the interior.
D) The cell will become flaccid.
E) The cell will become turgid.
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
A) It produces much less ATP than does oxidative phosphorylation.
B) It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
C) It is found in prokaryotic cells but not in eukaryotic cells.
D) It relies on chemiosmosis, which is a metabolic mechanism present only in the first cells' prokaryotic cells.
E) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?
A) in photosynthetic cells in the light, while photosynthesis occurs concurrently
B) in nonphotosynthesizing cells only
C) in cells that are storing glucose only
D) in all cells all the time
E) in photosynthesizing cells in the light and in other tissues in the dark
What are cells?
Smallest unit of life
Membrane bound structure containing organelles
What makes up a cell?
(which create organelles)
Density-dependent inhibition is explained by which of the following?
A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors.
B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.
C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor.
D) As cells become more numerous, more and more of them enter the S phase of the cell cycle.
E) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.
What explains anchorage dependence of animal cells in vitro or in vivo?
A) attachment of spindle fibers to centrioles
B) response of the plasma membrane to cell cycle controls
C) the makeup of the extracellular matrix of the substrate
D) the binding of cell-surface phospholipids to those of adjoining cells
E) the binding of cell-surface phospholipids to the substrate
A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away?
A) The cells originated in the nervous system.
B) The cells are unable to form spindle microtubules.
C) They have altered series of cell cycle phases.
D) The cells show characteristics of tumors.
E) They were originally derived from an elderly organism.
For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable?
A) It is safe enough to limit all apoptosis.
B) It does not alter metabolically active cells.
C) It only attacks cells that are density dependent.
D) It interferes with cells entering G0.
E) It interferes with rapidly dividing cells.
When human cells are preparing for cell division, how many strands of DNA are found in the cell?
92 strands of DNA
(normal = 46)
What does an X over a cell mean?
A) are frequently overexpressed in cancerous cells.
B) are cancer-causing genes introduced into cells by viruses.
C) can encode proteins that promote DNA repair or cell-cell adhesion.
D) often encode proteins that stimulate the cell cycle.
E) do all of the above.
Which of the following is true of embryonic stem cells but not of adult stem cells?
A) They can differentiate into many cell types.
B) They make up the majority of cells of the tissue from which they are derived.
C) They can continue to replicate for an indefinite period.
D) They can provide enormous amounts of information about the process of gene regulation.
E) One aim of using them is to provide cells for repair of diseased tissue.
A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following is a likely finding?
A) The cells from the two sources exhibit different patterns of DNA methylation.
B) Adult stem cells have more DNA nucleotides than their counterparts.
C) The two kinds of cells have virtually identical gene expression patterns in microarrays.
D) The nonstem cells have fewer repressed genes.
E) The nonstem cells have lost the promoters for more genes.
In recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). In order to make this conversion, what has been done to the adult cells?
A) A retrovirus is used to introduce four specific regulatory genes.
B) The adult stem cells must be fused with embryonic cells.
C) Cytoplasm from embryonic cells is injected into the adult cells.
D) An adenovirus vector is used to transfer embryonic gene products into adult cells.
E) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.
One successful form of gene therapy has involved delivery of an allele for the enzyme adenosine deaminase (ADA) to bone marrow cells of a child with SCID, and delivery of these engineered cells back to the bone marrow of the affected child. What is one major reason for the success of this procedure as opposed to many other efforts at gene therapy?
A) The engineered bone marrow cells from this patient can be used for any other SCID patient.
B) The ADA-introduced allele causes all other ADA-negative cells to die.
C) The engineered cells, when reintroduced into the patient, find their way back to the bone marrow.
D) No vector is required to introduce the allele into ADA-negative cells.
E) The immune system fails to recognize cells with the variant gene.
A mycoplasma is an organism with a diameter between 0.1 and 1.0 µm. What does the organism's size tell you about how it might be classified?
A) It must be a single-celled protist.
B) It must be a single-celled fungus.
C) It could be almost any typical bacterium.
D) It could be a typical virus.
E) It could be a very small bacterium.
Which of the following is a major cause of the size limits for certain types of cells?
A) limitation on the strength and integrity of the plasma membrane as cell size increases
B) the difference in plasma membranes between prokaryotes and eukaryotes
C) evolutionary progression in cell size; more primitive cells have smaller sizes
D) the need for a surface area of sufficient area to support the cell's metabolic needs
E) rigid cell walls that limit cell size expansion
Which of the following statements concerning bacteria and archaea cells is correct?
A) Archaea cells contain small membrane-enclosed organelles; bacteria do not.
B) Archaea cells contain a membrane-bound nucleus; bacteria do not.
C) DNA is present in both archaea cells and bacteria cells.
D) DNA is present in the mitochondria of both bacteria and archaea cells.
The evolution of eukaryotic cells most likely involved
A) endosymbiosis of an aerobic bacterium in a larger host cell–the endosymbiont evolved into mitochondria.
B) anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen–the anaerobic bacterium evolved into chloroplasts.
C) an endosymbiotic fungal cell evolved into the nucleus.
D) acquisition of an endomembrane system, and subsequent evolution of mitochondria from a portion of the Golgi.
Prokaryotes are classified as belonging to two different domains. What are the domains?
A) Bacteria and Eukarya
B) Bacteria and Archaea
C) Archaea and Protista
D) Bacteria and Protista
E) Bacteria and Fungi
If radioactive deoxythymidine triphosphate (dTTP) is added to a culture of rapidly growing bacterial cells, where in the cell would you expect to find the greatest concentration of radioactivity?
C) endoplasmic reticulum
Which organelle or structure is absent in plant cells?
B) Golgi vesicles
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
E) nucleic acids
The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence?
A) the loss of all nuclear function
B) the inability of the nucleus to divide during cell division
C) a change in the shape of the nucleus
D) failure of chromosomes to carry genetic information
E) inability of the nucleus to keep out destructive chemicals
Recent evidence shows that when chromosomes decondense during interphase, their DNA molecules do not intermingle. Instead, they occupy distinct territories within the nucleus. Considering the structure and location of the following structures, which is most likely to be involved in chromosome location?
A) nuclear pores
B) the nucleolus
D) the nuclear lamina
E) the nuclear matrix
A cell with a predominance of free ribosomes is most likely
A) producing primarily proteins for secretion.
B) producing primarily cytoplasmic proteins.
C) constructing an extensive cell wall or extracellular matrix.
D) digesting large food particles.
E) enlarging its vacuole.
Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
C) smooth endoplasmic reticulum
E) contractile vacuole
Which structure is the site of the synthesis of proteins that may be exported from the cell?
A) rough ER
D) Golgi vesicles
E) free cytoplasmic ribosomes
The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?
A) Transport vesicles fuse with one side of the Golgi and leave from the opposite side.
B) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
C) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
D) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
E) All of the above correctly describe polar characteristics of the Golgi function.
The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that
A) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope.
B) the nuclear envelope is not part of the endomembrane system.
C) the nuclear envelope is physically separated from the endoplasmic reticulum.
D) small vesicles from the Golgi fuse with the nuclear envelope.
E) nuclear pore complexes contain proteins.
Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal?
A) brain, organ system, nerve cell, nervous tissue
B) organ system, nervous tissue, brain
C) organism, organ system, tissue, cell, organ
D) nervous system, brain, nervous tissue, nerve cell
E) organ system, tissue, molecule, cell
Which of the following is not an observation or inference on which Darwin's theory of natural selection is based?
A) Poorly adapted individuals never produce offspring.
B) There is heritable variation among individuals.
C) Because of overproduction of offspring, there is competition for limited resources.
D) Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring.
E) A population can become adapted to its environment over time.
Systems biology is mainly an attempt to
A) analyze genomes from different species.
B) simplify complex problems by reducing the system into smaller, less complex units.
C) understand the behavior of entire biological systems.
D) build high-throughput machines for the rapid acquisition of biological data.
E) speed up the technological application of scientific knowledge.
Protists and bacteria are grouped into different domains because
A) protists eat bacteria.
B) bacteria are not made of cells.
C) protists have a membrane-bounded nucleus, which bacterial cells lack.
D) bacteria decompose protists.
E) protists are photosynthetic.
Which of the following best demonstrates the unity among all organisms?
A) matching DNA nucleotide sequences
B) descent with modification
C) the structure and function of DNA
D) natural selection
E) emergent properties
Compared with 31P, the radioactive isotope 32P has
A) a different atomic number.
B) a different charge.
C) one more proton.
D) one more electron.
E) one more neutron.
The reactivity of an atom arises from
A) the average distance of the outermost electron shell from the nucleus.
B) the existence of unpaired electrons in the valence shell.
C) the sum of the potential energies of all the electron shells.
D) the potential energy of the valence shell.E) the energy difference between the s and p orbitals
Which statement is true of all atoms that are anions?
A) The atom has more electrons than protons.
B) The atom has more protons than electrons.
C) The atom has fewer protons than does a neutral atom of the same element.
D) The atom has more neutrons than protons.
E) The net charge is 1-.
Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
A) The concentrations of products and reactants are equal.
B) The reaction is now irreversible.
C) Both forward and reverse reactions have halted.
D) The rates of the forward and reverse reactions are equal.
E) No reactants remain.
The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound:
What coefficients must be placed in the following blanks so that all atoms are accounted for in the products?
C6H12O6 → ____ C2H6O + ____ CO2
A) 1; 2
B) 3; 1
C) 1; 3
D) 1; 1
E) 2; 2
Why do you use
the scientific method?
To test a hypothesis
When would you use a dissecting microscope?
When you need to view the surface of a 3D object
And moderate magnification is sufficient
An increase in size
What is resolution?
Being able to distinguish
one entity from another
What is a covalent bond?
Bond where two atomsshare a pair of electrons
Occurs between molecules with polar covalent bonds
An interactions between partial charges
What is used to indicate
a hydrogen bond?
Dotted or dashed line
Cell membranes are asymmetrical. Which of the following is the most likely explanation?
A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium.
B) Cell membranes communicate signals from one organism to another.
C) The two sides of a cell membrane face different environments and carry out different functions.
D) The "innerness" and "outerness" of membrane surfaces are predetermined by genes.
E) Proteins can only be associated with the cell membranes on the cytoplasmic side.
Which of the following is true of the evolution of cell membranes?
A) Cell membranes have stopped evolving now that they are fluid mosaics.
B) Cell membranes cannot evolve if the membrane proteins do not.
C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids.
D) All components of membranes evolve in response to natural selection.
E) An individual organism selects its preferred type of cell membrane for particular functions.
Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth?
A) Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya.
B) Glycolysis neither uses nor needs O2.
C) Glycolysis is found in all eukaryotic cells.
D) The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle.
E) Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present in Earth's atmosphere.
- occurs in mitochondria
- involves krebs cycle and electron transport chain
- red in acidic
- purple in neutral
- green/yellow in basic
What does it mean if something is hydrophilic?
It “likes” water
It has numerous polar bonds, water forms H bonds with
these polar bonds
What does it mean if something is hydrophobic?
It does not interact with water
- swells cells/causes them to burst
- causes cells to shrink
- if the [H+] is 10-6 the pH is 6
- keeps plants from wilting
- decreases as solute concentration increases
- solutions have negative osmotic potential
- can be identified using Benedict's reagent