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Transcription is the process by which:
RNA is synthesized from DNA
Secondary structure is characterized by which one of the following types of interactions?
Hydrogen bonding within the peptide backbone
The genetic code is:
_____ The codons in mRNA specify the amino acids that are used to make a protein. TRUE (a) or FALSE (b).
_____ Sixty-one of the 64 possible codons specify amino acids, whereas the other three are stop codons. Each of the 61 codons specifies just one amino acid. TRUE (a) or FALSE (b).
_____ Some amino acids are specified by just one codon, whereas others are specified by multiple codons. TRUE (a) or FALSE (b).
_____ The limitations of the genetic code are such that a single amino acid may be specified by no more than four codons. TRUE (a) or FALSE (b).
_____ Because there are four RNA nucleotides and each codon is three nucleotides long, there are 64 possible codons, each of which directs the ribosome to incorporate a specific amino acid into a growing polypeptide chain. TRUE (a) or FALSE (b).
Suppose you use a match to ignite a sheet of paper from your notebook, and allow the fire to continue until the burning stops. If you could measure all the energy in the resulting combustiond), would you predict this amount to be more than, less than, or the same amount as the amount of potential energy in the starting sheet of paper? (You should ignore the activation energy provided by the match to light the paper.)
the same energy as the paper
The highest free energy of a reaction is found in the (s) of that reaction.
True or False: if a DNA molecule is visualized as a wood screw from a hardware store, the threads in the screw are spaced identical distances from each other.
True or False: during transcription of a given protein-coding gene, both strands are used as template.
A template strand of DNA is read in the direction in order to direct synthesis of RNA in the direction.
During photosynthesis, is reduced to .
carbon dioxide; glucose
Which of these summarizes the overall reactions of cellular respiration?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
Arrange the steps in the Calvin cycle in order from earliest to latest.
carboxylation, reduction, regeneration
True or False: the individual polypeptide chains in a multi-subunit protein each have their own primary, secondary, and tertiary structure.
You decide that you should write the three letter abbreviation for arginine instead. You write:
For the molecule of angiotensin II above, you would write the one-letter abbreviation as:
None of the above
The energy in organic molecules is released in a series of steps because:
it is not possible to release it in a single step.
more energy can be harvested for cellular use in multiple steps than from a single step.
When fats are used as an energy source, the fatty acids are broken down to acetyl-CoA. That means that fats bypass the reactions of ___ and enter the respiratory pathway at ________.
glycolysis; the citric acid cycle
No, because with a leaky membrane, H+ gradient cannot be maintained.
a competitive inhibitor
The reaction is spontaneous.
An enzyme catalyzes the transfer of a phosphate group to ADP from an organic molecule to form ATP.
The polyA tail was not formed.
Disorders of which organelle are often associated with defects in transport from compartment to compartment, resulting in poor sorting of protein components within the cell?
The signal sequence on the lysosomal protein is defective.
the unequal sharing of electrons between an atom with a partial positive charge and an atom with a partial negative charge
the number and identity of the atoms present in the reactants
Complete the following sentence.
An exon is _______________________
part of an intact, mature mRNA that leaves the nucleus
Because ADP has only two phosphate groups.
No; whereas the noncovalent bonds determine the shape of a protein, the peptide bonds are required to hold the amino acids together.
6 start codons and 6 stop codons.
all of the above
is an anabolic pathway
an exergonic reaction
B is converted to C
The image above depicts what stage of mitosis?
Which cell adhesion molecule is particularly good at attaching the cell to the basement membrane?
Paramecium is a single-cell eukaryotic organism that can reproduce by mitotic ell division. Prior to the M phase of the cell cycle, which of the following must occur?
The cell must replicate its chromosomes.
True or false: Sequences that are conserved (i.e., similar in many different organisms) are unlikely to be functionally important.
Homologous chromosomes can be defined as:
The correct sequence of steps in the M phase of the cell cycle is _________________ .
prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
Which of the following would be most likely to lead to the development of cancer?
the activation of an oncogene and an inactivating mutation in a tumor suppressor gene
Complex organisms can be characterized as having:
Which of the following statements provides evidence that organelles (e.g., mitochondria and chloroplasts) originated billions of years ago as a result of primitive eukaryotic cells engulfing free-living bacterial cells?
When we say that DNA replication is semiconservative, we mean that:
when DNA is replicated, each new double helix contains one parental strand and one newly synthesized daughter strand.
The technique of Sanger sequencing takes advantage of the fact that dideoxynucleotides (nucleotides in which the 3’ hydroxyl group is absent) act as
Consider a diploid organism (2n) with a haploid complement (n) of four chromosomes. At Prophase I, how many total chromosomes will be present in a cell?
eight, four pairs of homologous chromosomes
Which of the following is not true about how communities of cells interact within tissues?
All cells in a tissue carry out the same function independently.
One of the DNA replication proteins/enzymes is altered in a way the results in an increased rate of single base changes in the newly synthesized DNA strand. Which function is most likely to be disrupted?
the proofreading function of DNA polymerase
How would the signal of a G protein-coupled receptor, without ligand, be affected if you made an enzyme that converted GDP to GTP constitutively?
The G protein would be active and signaling despite the lack of ligand.
Dynamic instability of microtubules:
allows microtubules to perform their functions.
Which of the following enzymes would be the first to bind to the DNA sequences at the origin of replication?
change the entire amino acid sequence downstream from the site of the insertion or deletion.
Which of the following happens during Prophase I of meiosis?
recombination between non-sister chromatids of homologous chromosomes
Homologous pairs of chromosomes are separated during ________________ .
The process of gene duplication and divergence refers to (select all that apply):
the creation of gene families, which are genes that are similar across a range of organisms.
Mismatch repair, base excision repair, and nucleotide excision repair are similar in that (select all that apply):
each uses an undamaged segment of DNA as the template to repair a damaged segment of DNA.
The phenotype of an individual results from an interaction between:
genotype and the environment.
Are all point mutations SNPs?
No, because SNPs require a certain frequency in the population.
When DNA with variable number tandem repeats (VNTRs) is sequenced and visualized on a gel, the resulting fragments separate according to their:
What stage of meiosis is represented above (where sister chromatids separate)?
Which one of these is NOT an essential player in communication between two cells?
What is the first step in cell signaling/communication?
signaling molecule binding to its cellular receptor
Receptor kinases are activated by:
When a G protein encounters an activated receptor, the alpha subunit exchanges GDP for GTP, dissociates from the beta and gamma subunits, and becomes active.
Several signaling pathways can take place simultaneously in a single cell, and the cellular response depends on the integration of several signals.
A collection of cells that work together to perform a specific function is a:
Cell adhesion molecules allow cells to attach to other cells and to extracellular matrix proteins.
Flagella and cilia contain cell adhesion molecules that propel cells through aqueous environments.
Levels of proteins called cyclins continue to increase during the cell cycle.
Meiotic cell division is a form of cell division that reduces the number of chromosomes by half to produce haploid gametes of spores that have one copy of each chromosome.
Only one strand of DNA is used for DNA synthesis.
A recombinant DNA molecule can be made by cutting DNA from two organisms with the same restriction enzyme and then using DNA ligase to join them.
Enzymes that unwind the DNA molecule are called
Gel electrophoresis allows DNA to be separated according to
Diploid organisms have two copies of each chromosome, and these two copies are called homologous chromosomes.
Sequences that are repeated in the genome can make sequence assembly difficult.
An example of a mutation includes:
all of the above
Mismatch repair provides a backup mechanism for mistakes not caught by the proofreading function of DNA helicase.
all of the above
A person’s genotype can be homozygous. This means:
he or she has inherited two alleles of the same type (one from each parent)
Genetic variation can be:
all of the above
Telomerase prevents chromosomes from shortening after each round of replication by adding a short stretch of DNA to the ends of chromosomes.
What does it mean to say that an allele is “fixed” in the population?
It is an indication of no genetic variation at that locus in the population.
From an evolutionary perspective, germ-line mutations are more significant than somatic mutations. This is because:
only germ-line mutations will appear in an individual’s descendants.
Human ABO blood groups are determined by a single gene with 3 alleles: A, B, and O. In a sample of 300 individuals, 100 are blood type A and genotype AA, 100 are blood type B and genotype BO, and 100 are blood type O and genotype OO. What are the allele frequencies?
33.3% A, 16.6% B, 50% O
In regions where malaria is prevalent, the S allele is beneficial because:
it causes red blood cells to distort, which makes them less hospitable to Plasmodium, the parasite that causes malaria.
A population of charmingly charismatic rodents, population A, lives on a small island. The population consists of 100,000 individuals.
Are all individuals of A genetically identical?
A drawback of the biological species concept is that it cannot be applied to:
extinct and asexual organisms.
The phenotypes of complex traits vary with both genotype and environment. An important implication of this is that:
All of these choices are correct.
A bacteriologist is studying two asexually reproducing strains of E. coli. The two require different amounts of trace minerals for survival; on these grounds, the bacteriologist determines that they are separate species. In making his determination, he is using which species concept?
ecological species concept
A pea plant is heterozygous (Aa) for seed color and heterozygous (Bb) for seed shape. According to Mendel’s principle of independent assortment:
a gamete that receives the dominant allele for seed color is equally likely to receive the dominant allele for seed shape as it is the recessive allele for seed shape.
Hemophilia is a sex-linked recessive trait in humans. If a carrier female (heterozygous for the trait) mated with a normal male, what would be the expected outcome(s)?
None of the daughters would have hemophilia, and half of the sons would have hemophilia.
Red-green color blindness is a sex-linked recessive trait in humans. If a non-carrier female (homozygous for the nonmutant allele) mated with an affected man, what would be the expected outcome(s)?
None of the offspring (sons or daughters) would be color blind.
You begin an experiment with 2 populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.e., they are clones). You grow them up in flasks on a lab bench under identical conditions with unlimited resources. After 10,000 generations, you analyze the genome of each population. Do you expect the genomes of each population to be identical after 10,000 generations?
No, because mutation and natural selection (once genetic variation is present) were factors in this experiment.
the common ancestor from which the descendent species diverged.
Characters that are similar because of descent from a common ancestor are _____; characters that are similar due to convergent evolution are _____.
All of the answer options are correct.
marine life during initial diversification of animals in the Cambrian Period 505 million years ago.
During the end-Permian mass extinction:
All of the answer options are correct.
What is a disadvantage of using fossils to reconstruct phylogenetic history?
The probability of fossilization varies among species.
Which organism is most likely to be fossilized?
What is the highest recombination frequency between two genes on the same chromosome?
Sometimes certain diseases affect all sons of an affected father, even when the mother is unaffected. What is the best explanation of this?
The disease-related gene is on the Y chromosome.
Why is the fossil record not a complete catalogue of biological history?
Not all organisms fossilize with equal probability.
Recent discoveries of fossils that surprisingly retain some coloration are the result of the preservation of:
cellular melanosomes that produced pigments
When X-linked traits are recessive:
males who express the trait receive the recessive allele from their mothers and carry the recessive allele on their X chromosomes
In what kind of environment are fossils most likely to form?
shallow lake bed
One reason we see relatively little genetic variation among human regional populations is that:
humans migrated out of Africa so recently that we haven’t had enough time for regional variation to accumulate.
Statistical analysis of genetic variation within and among human populations―including those we identify as different races―reveals:
more genetic variation within groups than we see between groups.
In what types of rocks are fossils most likely to be found?
After you have found a new species of ape, you spend 10 years in the field seeking a fossil of its ancestor. You fail. This lack of fossil data:
is expected, because the fossil record is incomplete
What is the definition of neoteny?
retention of juvenile characteristics in an adult
How does the level of genetic variation in humans typically compare to other species?
lower than other species
Where did Homo sapiens evolve?
Which human populations have the highest levels of genetic variation?
Skin color is an example of a human trait influenced by natural selection. What factor(s) has/have directly shaped variation in skin color?
intensity of sunlight
Why do we think that male Neanderthals mated with non-African ancestral Homo sapiens?
Because Neanderthal nuclear DNA sequences are present in the human gene pool, and Neanderthal mtDNA sequences are not.
Why didn’t Mendel discover the nature of sex chromosomes in his pea plants?
Peas and most other plants do not have sex chromosomes.
Inbred lines of animals, such as laboratory mice, are useful for studying complex traits because:
individuals are genetically identical, so differences in traits must be due to environmental differences.
only affect males, and affect all sons of an affected male.
What patterns in a pedigree characterize a trait determined by the mitochondrial genome?
All offspring of an affected female show the trait, and males never transmit the trait to their offspring.
Some inherited traits show incomplete dominance, in which the phenotype of the heterozygous genotype is intermediate between those of the two homozygous genotypes.
X-linked genes show a criss-cross inheritance pattern, in which the X-chromosome with the mutant gene that is present in males in one generation will only be present in males of subsequent generations.
Separated populations can diverge as a result of genetic drift, with no role for natural selection.
A _________ group includes some, but not all, of the descendants of a common ancestor.
Data from phylogeny and fossils are often in agreement, providing strong evidence for evolution.
The number of branches on a phylogenetic tree, not the order of the branches indicates the sequence of events in time.
The correct order for classification of species is:
Kingdom, Phylum, Class, Order, Family, Genus, Species
Construction of phylogenetic trees is purely an academic pursuit, and serves no practical purpose.
Some racial differences, such as skin color and resistance to malaria, probably have arisen via natural selection.
Humans have a huge amount of genetic variation, with 1 in every 10 base pairs varying among individuals.
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