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Using the yeast signal transduction pathways, both types of mating cells release the mating factors. These factors bind to specific receptors on the correct cells,
What is most likely to happen to an animal's target cells that lack receptors for local regulators?
D) They might not be able to multiply in response to growth factors from nearby cells.
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?
D) signal molecule
Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP?
A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
B) binding with a receptor protein that enters the nucleus and activates specific genes.
D) They control gene expression.
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?
D) receptor tyrosine kinases
The receptors for a group of signaling molecules known as growth factors are often
D) receptor tyrosine kinases.
A) brings a conformational change to each protein.
Which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid?
C) insufficient ATP levels in the cytoplasm
Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?
E) receptor tyrosine kinase activity
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of
If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one approach might be to design a compound
C) to block G protein activity in liver cells.
Which of the following statements is true of signal molecules?
E) Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled receptors.
What explains the increased concentration of Ca++ in the ER?
A) Calcium ions are actively imported from the cytoplasm into the ER.
A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following?
C) a decrease in transcriptional activity of certain genes
How can one hormone, such as estrogen, mediate so many effects?
D) Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding.
A) the nucleus only
B) the ER only
C) ligand binding only
D) mitochondrial protein leakage only
E) all of the above
What do we mean when we use the terms monohybrid cross and dihybrid cross?
C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one.
Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
D) One phenotype was completely dominant over another.
B) Traits are inherited in discrete units, and are not the results of "blending."
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
D) that the parents were both heterozygous for a single trait
A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?
Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that
C) traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.
The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?
D) All of the genes controlling the traits behaved as if they were on different chromosomes.
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
D) anaphase I of meiosis
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
C) the probability that either one of two independent events will occur
Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
B) roan × roan
Cystic fibrosis. Which of the following terms best describes this?
E) skin pigmentation in humans
E) environmental factors such as soil pH
Which of the following provides an example of epistasis?
C) In rabbits and many other mammals, one genotype (cc) prevents any fur color from developing.
Remarkably, all the white-eyed flies were male. What was the explanation for this result?
B) The gene involved is on the X chromosome.
A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following describes her expected phenotype?
D) normal female
D) males are hemizygous for the X chromosome.
What kinds of offspring would you expect from the cross of a black female and an orange male?
D) tortoiseshell females; black males
Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?
A) XcXc and XcY
E) XCXc and XCY
Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?
B) a male inherits only one of the two X-linked genes controlling hair color.
In his transformation experiments, what did Griffith observe?
B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?
In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.
D) Erwin Chargaff
Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?
A) the diameter of the helix
It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?
A) sequence of bases
C) A + C = G + T
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is
A) 3' UCA 5'.
C) ATP, RNA, and DNA
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
C) DNA was the first genetic material.
B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.
In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?
C) RNA polymerase II
D) several transcription factors (TFs)
What is a ribozyme?
B) an RNA with enzymatic activity
A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that
A) many noncoding stretches of nucleotides are present in pre-mRNA.
B) can allow the production of proteins of different sizes or even different proteins from a single mRNA.
D) The molecule is digested by exonucleases since it is no longer protected at the 5' end.
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is
E) the proteins on its surface and that of the host.
Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?
D) A large number of phages are released at a time.
Why do RNA viruses appear to have higher rates of mutation?
Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory?
E) Viral genomes are usually similar to the genome of the host cell.
The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur?
C) The plants would develop the typical symptoms of TMV infection.
Which viruses have single-stranded RNA that acts as a template for DNA synthesis?
What is the function of reverse transcriptase in retroviruses?
B) getting vaccinated
Which of the following represents a difference between viruses and viroids?
B) Viruses have capsids composed of protein, whereas viroids have no capsids.
A) vertical transmission is transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant.
What are prions?
A) ability of the infected cell to undergo normal cell division
Antiviral drugs that have become useful are usually associated with which of the following properties?
B) interference with viral replication
Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?
E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.
Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
C) genetic material composed of nucleic acid
C) become capable of human-to-human transmission.
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have
D) T4 protein and T4 DNA.
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the
E) bonding of the anticodon to the codon and the attachment of the proper amino acids to tRNAs.
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that
B) the rules for base pairing between the third base of a codon and tRNA are flexible (“wobble bases”).
Which of the following is the first event to take place in translation in eukaryotes?
B) base pairing of activated methionine-tRNA to AUG of the messenger RNA
B) polypeptide factors plus GTP
C) It introduces a premature stop codon into the mRNA.
E) either an insertion or a deletion of a base.
Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?
B) a base deletion near the start of a gene
The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in
D) a polypeptide missing an amino acid.
B) several transcription factors have bound to the promoter.
Which of the following is not true of a codon?
D) It extends from both ends of a tRNA molecule.
The anticodon of a particular tRNA molecule is
A) complementary to the corresponding mRNA codon.
Which is a correct statement concerning the insect circulatory system?
A) The circulating fluid bathes tissues directly.
Organisms in which a circulating body fluid is distinct from the fluid that directly surrounds the body's cells are likely to have
B) a closed circulatory system.
In which animal does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?
B) two atria; one ventricle
To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation, an organism would need a(n)
E) four-chambered heart.
E) 3, 5, and 6
D) vena cava → right atrium → ventricle → pulmonary circuit
Damage to the sinoatrial node in humans
D) would disrupt the rate and timing of cardia muscle contractions.
If the atrioventricular node could be surgically removed from the heart without disrupting signal transmission to the Purkinje fibers, what would be the effect?
E) Atria and ventricles would contract at about the same time.
Why is the velocity of blood flow the lowest in capillaries?
E) The total surface area of the capillaries is larger than the total surface area of the arterioles.
C) I and II only
D) decrease of the systolic blood pressure
Human plasma proteins include which of the following?
C) I and III only
B) in the peripheral nervous system
The general functions of the nervous system include which of the following?
II. motor output
III. sensory input
E) I, II, and III
Integration of simple responses to certain stimuli, such as the patellar reflex, is accomplished by which of the following?
A) spinal cord
D) The outside of a cell is negative with respect to the inside of a cell.
The sodium-potassium pump of neurons pumps
D) Na+ out of the cell and K+ into the cell.
Which of following is a true statement about the threshold potential of a membrane?
D) It is the depolarization that is needed to generate an action potential.
B) The intensity of a stimulus is related to the magnitude of the action potential.
Repolarization of the membrane of a neuron after an action potential is a consequence of which of the following?
II. Na+ channels inactivatingIII. K+ channels opening
A) Sodium gates open.
Saltatory conduction is a term applied to conduction of impulses
E) along myelinated nerve fibers.
E) a frog leaping between lily pads
C) Neural impulses cause the release of chemicals that diffuse across the gap.
Neurotransmitters categorized as inhibitory would not be expected to
A) bind to receptors.
C) open Na+ channels.
Which of the following statements is true regarding temporal summation?
B) Several action potentials arrive in fast succession without allowing the postsynaptic cell to return to its resting potential.
A neurotransmitter can trigger different responses in postsynaptic cells due to which of the following?
A) receptor mode of action
B) receptors present
C) concentration of neurotransmitter
D) A and B only
E) A, B, and C
Neurotransmitters affect postsynaptic cells by
A) initiating signal transduction pathways in the cells.
B) causing molecular changes in the cells.
C) affecting ion-channel proteins.
D) altering the permeability of the cells.
E) all of the above
C) formed from layers of connective tissue.
The divisions of the nervous system that have antagonistic actions, or opposing actions are
Which of the following activities would be associated with the parasympathetic division of the nervous system?
A) rest and digestion
What would be most affected if an accident caused trauma to the hypothalamus?
D) regulation of body temperature
E. medulla oblongata
E. medulla oblongata
E. medulla oblongata
E. medulla oblongata
By comparing the size and degree of convolution of various vertebrate cerebral cortices, biologists would gain insight into the relative
D) sophistication of behaviors.
D) chemicals involved in brain communications.
An impulse relayed along a myelinated axon "jumps" from ________ to ________.
C) node of Ranvier; node of Ranvier
E) Schwann cells
Which of these causes the release of neurotransmitter molecules?
D) an action potential reaching the end of the axon
B) The brief refractory period prevents reopening of voltage-gated Na+ channels.
C) are triggered by a depolarization that reaches the threshold.
Where are neurotransmitter receptors located?
C) on the postsynaptic membrane
Which disease or disorder is caused by the death of brain neurons that release dopamine?
E) Parkinson's disease
B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
E) DNA in both daughter cells would be radioactive.
In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?
B) No replication fork will be formed.
Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?
C) DNA polymerase III
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?
C) gaps left at the 5' end of the lagging strand
3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?
D) 5' A C G U U A G G 3'
C) to add nucleotides to the 3' end of a growing DNA strand
The leading and the lagging strands differ in that
A) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
E) DNA polymerase can only add nucleotides to the free 3' end.
A) relieving strain in the DNA ahead of the replication fork
C) It joins Okazaki fragments together.
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
D) single-strand binding proteins
Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells are impaired in what way?
D) They cannot repair thymine dimers.
Which of the following would you expect of a eukaryote lacking telomerase?
D) a reduction in chromosome length in gametes
Which of the enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?
DNA polymerase I
Which of the enzymes separates the DNA strands during replication?
Which of the enzymes synthesizes short segments of RNA?
In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding?
D) the 30-nm chromatin fiber
D) It consists of a single linear molecule of double-stranded DNA plus proteins.
B) The cell's DNA couldn't be packed into its nucleus.
Why do histones bind tightly to DNA?
A) Histones are positively charged, and DNA is negatively charged.
Which of the following represents the order of increasingly higher levels of organization of chromatin?
A) nucleosome, 30-nm chromatin fiber, looped domain
Which of the following statements describes chromatin?
C) Heterochromatin is highly condensed, whereas euchromatin is less compact.
What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?
A) 2:1 male to female
A) The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
How would one explain a testcross involving F1 dihybrid flies in which more parental-type offspring than recombinant-type offspring are produced?
A) The two genes are closely linked on the same chromosome.
What does a frequency of recombination of 50% indicate?
A) The two genes are likely to be located on different chromosomes.
What is the reason that linked genes are inherited together?
A) They are located close together on the same chromosome.
B) 1% frequency of recombination between two genes
Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?
A) The frequency of crossing over varies along the length of the chromosome.
If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis?
C) 1/4 of the gametes will be n + 1, 1/4 will be n - 1, and 1/2 will be n.
If a man and woman both with genotype HnHb have a son, what is the chance that he will eventually be bald?
Which of the following might then occur to make the cancer worse?
B) expression of inappropriate gene products
An inversion in a human chromosome often results in no demonstrable phenotypic effect in the individual. What else may occur?
B) Some abnormal gametes may be formed.
D) nondisjunction or translocation in either parent
Down syndrome has a frequency in the U.S. population of ~1/700 live births. In which of the following groups would you expect this frequency to be significantly higher?
E) No groups have such higher frequency.
A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?
D) One member of the couple underwent nondisjunction in gamete production.
If this depends on the sex of the parent who transmits the gene, which of the following must be true?
D) Methylation must be reversible in ovarian and testicular cells.
Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?
B) chloroplast inheritance
The pedigree in Figure 15.3 shows the transmission of a trait in a particular family. Based on this pattern of transmission, the trait is most likely
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?
D) carbon, hydrogen, nitrogen, oxygen
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?
C) Virtually all organisms require the same elements in the same quantities.
Why is each element unique and different from other elements in chemical properties?
C) Each element has a unique number of protons in its nucleus.
Knowing just the atomic mass of an element allows inferences about which of the following?
D) the number of protons plus neutrons in the element
Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom?
D) approximately 16 daltons
The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.
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?
C) Some carbon atoms in nature have more neutrons.
One difference between carbon-12 ( ) is that carbon-14 ( ) has
C) two more neutrons than carbon-12.
An atom has 6 electrons in its outer shell. How many unpaired electrons does it have?
The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?
D) It has 8 electrons in its outer electron shell and it is inert.
E) 15 protons and 15 electrons.
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?
An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
B) It would form ions with a +2 charge.
If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal?
B) a surface made with carbon and hydrogen atoms covalently bonded together
A covalent chemical bond is one in which
C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.
What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
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.
D) nonpolar covalent bonds.
B) a polar covalent bond
A covalent bond is likely to be polar when
A) one of the atoms sharing electrons is much more electronegative than the other atom.
Which of the following molecules contains the most polar covalent bond?
C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
A) covalent bond
Which of the following explains most specifically the attraction of water molecules to one another?
D) hydrogen bond
Van der Waals interactions result when
B) electrons are not symmetrically distributed in a molecule.
A) a covalent bond
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.
Which of the following correctly describes any reaction that has reached chemical equilibrium?
B) The rate of the forward reaction is equal to the rate of the reverse reaction.
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
C) polar covalent bonds.
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?
B) a hydrogen bond
The partial negative charge in a molecule of water occurs because
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
Water molecules are able to form hydrogen bonds with
A) compounds that have polar covalent bonds.
Which of the following effects is produced by the high surface tension of water?
B) A water strider can walk across the surface of a small pond.
Which of the following takes place as an ice cube cools a drink?
B) Kinetic energy in the drink decreases.
A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie?
D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C
Liquid water's high specific heat is mainly a consequence of the
C) absorption and release of heat when hydrogen bonds break and form.
D) hydrogen bonds
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
C) the release of heat by the formation of hydrogen bonds
B) The water molecules with the most heat energy evaporate more readily.
D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
Hydrophobic substances such as vegetable oil are
A) nonpolar substances that repel water molecules.
How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution?
E) 6.02 × 1023
Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
C) 1 L of 1.0 M NaCl
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
You have a freshly prepared 1 M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample?
E) 6.02 × 1022
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.
Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
If the pH of a solution is decreased from 9 to 8, it means that the
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.
Which of the following statements is true about buffer solutions?
D) They maintain a relatively constant pH when either acids or bases are added to them.
E) both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
Research indicates that acid precipitation can damage living organisms by
D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth.
If a solution has a pH of 7, this means that
C) the concentration of H+ ions in the water equals the concentration of OH- ions in the water.
Increased atmospheric CO2 concentrations might have what effect on seawater?
D) Seawater will become more acidic, and carbonate concentrations will decrease.
How would acidification of seawater affect marine organisms?
D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals.
When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using
C) a transmission electronic microscope.
The advantage of light microscopy over electron microscopy is that
C) light microscopy allows one to view dynamic processes in living cells.
A primary objective of cell fractionation is to
D) separate the major organelles so that their particular functions can be determined.
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
B) the size and weight of 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?
E) nucleus, mitochondria, ribosomes
E) an endoplasmic reticulum.
Which of the following is a major cause of the size limits for certain types of cells?
D) the need for a surface area of sufficient area to support the cell's metabolic needs
A) Archaea cells contain small membrane-enclosed organelles; bacteria do not.
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) Bacteria and Archaea
Which organelle or structure is absent in plant cells?
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
A cell with a predominance of free ribosomes is most likely
B) producing primarily cytoplasmic proteins.
Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
C) smooth endoplasmic reticulum
The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?
The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by
C) the function of the Golgi apparatus in sorting and directing membrane components.
Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?
Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells?
C) Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?
B) smooth ER
Which of the following produces and modifies polysaccharides that will be secreted?
D) Golgi apparatus
Which of the following contains hydrolytic enzymes?
Which organelle often takes up much of the volume of a plant cell?
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?
D) in the nucleus, mitochondria, and chloroplasts.
In light of the endosymbiont theory for the evolutionary origin of mitochondria, where is most ATP synthesis likely to occur in prokaryotic cells?
D) on the plasma membrane
What eukaryotic organelles or features might have evolved as a part of, or as an elaboration of, the endomembrane system?
D) nuclear envelope
Which type of organelle is found in plant cells but not in animal cells?
How does the cell multiply its peroxisomes?
D) They split in two after they become sufficiently large.
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
D) cytoskeletal structures
A) microtubules and motor proteins
The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is
A) a mitochondrion.
Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?
C) both flagella and motile cilia
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to
C) separate chromosomes during cell division.
Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to
E) move vesicles around the cell.
C) plant cell walls
Which of the following is a characteristic common to all of these extracellular structures?
They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.
The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following?
Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through
E) gap junctions.
D) mitochondrial proteins
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
B) catabolic pathways
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
B) loses electrons and loses potential energy.
Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?
B) Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O).
Which of the following statements describes the results of this reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A) C6H12O6 is oxidized and O2 is reduced.
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