AP Bio Tri 2 Exam Multiple Choice
Probability that the genotype Aa will be produced by the parents Aa x Aa
1/2
One of the affected males from the third generation has a child with a female who is a carrier. For the pedigree shown above, which of the following best expresses the probability that the couple's first son will be affected with the disorder?
50%
The probability that Matthew and Jane's first child will be an achondroplastic dwarf is
50%
The vertebrate forelimb initially develops in the embryo as a solid mass of tissue. As development progresses, the solid mass near the end of the forelimb is remodeled into individual digits. Which of the following best explains the role of apoptosis in remodeling of the forelimb?
Apoptosis involves the regulated activation of proteins in specific cells of the developing forelimb that leads to the death of those cells.
Enzyme used during replication to attach Okazaki fragments to each other
DNA ligase
Which of the following correctly explains where DNA replication will begin on the strand oriented 5'→3', reading from left to right?
DNA replication will be initiated immediately to the left of the RNA, since DNA polymerase requires an RNA primer.
Which of the following correctly explains the process shown in Figure 1 ?
Initiation of transcription is occurring because a strand of RNA is being produced from a DNA template strand.
Which of the following statements best describes the role of cyclic AMP in the signal transduction pathway?
It acts as a second messenger that helps relay and amplify the signal within the cell.
The genotypes of Matthew and Jane are best represented as
Matthew- aa Jane- Aa
Enzyme used in the synthesis of mRNA
RNA polymerase
Which of the following best explains why there is no growth on plate II?
The initial E. coli culture was not ampicillin-resistant.
Which of the following statements best describes how a growth factor stimulates cell division from outside a cell?
The growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activates specific target genes.
The researchers calculate a chi-square value of 4.6 and choose a significance level of p=0.05. Which of the following statements best completes the chi-square goodness-of-fit test?
The null hypothesis cannot be rejected because the chi-square value is less than the critical value.
Researchers studying cell cycle regulation in budding yeast have observed that a mutation in the CDC15 gene causes cell cycle arrest in telophase when the yeast cells are incubated at an elevated temperature. Which of the following statements best predicts the effect of the cell cycle arrest on proliferating yeast cells?
The yeast cells will replicate their chromosomes but will fail to complete cytokinesis.
Plates I and III were included in the experimental design in order to
demonstrate that the E. coli cultures were viable
DNA replication occurs
during the S phase of the cell cycle
Probability that the genotype ccdd will be produced by the parents CcDd x CcDd
1/16
Probability that the genotype Rr will be produced by the parents Rr x rr
1/2
Probability that the genotype TTSs will be produced by the parents TTSs x TtSS
1/4
If three children are born to Matthew and Jane, what are the chances that the first two children will not express the trait but that the third child will be an achondroplastic dwarf?
1/8
In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue-eyed offspring are produced. If the blue-eyed sheep are mated with each other, what percent of their offspring will most likely have brown eyes?
25%
The mRNA transcribed from the DNA would read
5' AUC AAG UUU GGC GCA UUG UAA 3'
The diagram above shows a developing worm embryo at the four-cell stage. Experiments have shown that when cell 3 divides, the anterior daughter cell gives rise to muscle and gonads and the posterior daughter cell gives rise to the intestine. However, if the cells of the embryo are separated from one another early during the four-cell stage, no intestine will form. Other experiments have shown that if cell 3 and cell 4 are recombined after the initial separation, the posterior daughter cell of cell 3 will once again give rise to normal intestine. Which of the following is the most plausible explanation for these findings?
A cell surface protein on cell 4 signals cell 3 to induce formation of the worm's intestine.
In the pedigree above, circles represent females, squares represent males, and shaded figures represent individuals expressing a specific trait. The expression of this trait is most likely due to which of the following?
Autosomal recessive inheritance
Which of the following is probably the genotype of the dark, short-haired parent in cross I?
CCBB
In cross II, the genotype of the dark, short-haired parent is
CcBb
In which of the following would there NOT be a change in the amino acid sequence of the peptide coded for by this DNA?
Changing 3' AAA 5' to read 3' AAG 5'
When DNA replicates, each strand of the original DNA molecule is used as a template for the synthesis of a second, complementary strand. Which of the following figures most accurately illustrates enzyme-mediated synthesis of new DNA at a replication fork?
D (multiple arrows out of 3' to 5' and one arrow from 3' to 5')
Enzyme used to position nucleotides during DNA replication
DNA polymerase
Which of the following is most likely to create genetic variation in a population?
DNA polymerase errors during replication
Plates that have only ampicillin-resistant bacteria growing include which of the following?
IV only
Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?
In involves enzymes activating other enzymes.
The Trp operon is a coordinately regulated group of genes (trpA-trpE) that are required for tryptophan biosynthesis in E. coli. Based on the figure above, which of the following correctly describes the regulation of the Trp operon?
In the presence of tryptophan, the repressor is active and binds to the Trpoperator, preventing RNA polymerase from transcribing the operon.
Which of the following best explains how the development of phenotypic female Australian dragon lizards with a ZZ genotype occurs when incubation temperatures are above 32°C?
Incubation temperatures above 32°C inhibit the genes on the Z chromosome that produce proteins necessary for male development.
Which of the following correctly describes the relationship of the dark-coat-color allele to the albino condition?
It is dominant.
Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different numbers of chromosomes?
Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.
Gregor Mendel's pioneering genetic experiments with pea plants occurred before the discovery of the structure and function of chromosomes. Which of the following observations about inheritance in pea plants could be explained only after the discovery that genes may be linked on a chromosome?
Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other.
Which of the following statements best explains why there are fewer colonies on plate IV than on plate III?
Not all E. coli cells are successfully transformed.
Which of the following statements best explains the structure and importance of plasmids to prokaryotes?
Plasmids are circular, double-stranded DNA molecules that provide genes that may aid in survival of the prokaryotic cell.
Enzyme found in retroviruses that produce DNA from an RNA template
Reverse transcriptase
Which of the following is the best explanation for the fragment pattern for individual X ?
She is the mother's child from another marriage.
Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells?
Shorter cell cycle
Erwin Chargaff investigated the nucleotide composition of DNA. He analyzed DNA from various organisms and measured the relative amounts of adenine (A), guanine (G), cytosine (C), and thymine (T) present in the DNA of each organism. Table 1 contains a selected data set of his results. Which of the following statements best explains the data set?
Since the %A and the %T are approximately the same in each sample, adenine and thymine molecules must pair up in a double-stranded DNA molecule.
The data above represent the results of three different crosses involving the inheritance of a gene that determines whether a certain organism is blue or white. Which of the following best explains the mechanism of inheritance of the gene?
The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2.
The banding patterns of the DNA fragments reveal that
The banding patterns of the DNA fragments reveal that
The students choose a significance level of p=0.01. Which of the following statements best completes the next step of the chi-square goodness-of-fit test?
The calculated chi-square value is 10.48, and the critical value is 11.35.
Based on the model of eukaryotic cell cycle regulation shown in the figure, which of the following best describes the effect of a drug that blocks the production of the mitotic cyclin?
The cell would be prevented from entering mitosis, and the cell would stop dividing.
Which of the following statements best explains how the genes for antibiotic resistance can be transmitted between bacteria without the exchange of bacterial chromosomal DNA?
The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria.
The following the DNA sequence is a small part of the coding (nontemplate) strand from the open reading frame of β-hemoglobin gene. Given the codon chart listed below, what would be the effect of a mutation that deletes the G at the beginning of the DNA sequence?
The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point.
Which of the following is the most likely explanation of the results?
The two genes are linked on an autosome.
Figure 1 represents a metabolic process involving the regulation of lactose metabolism by E. colibacteria. Lactose is utilized for energy by E. coli when glucose is not present. Allolactose is an isomer of lactose that is in the environment of these bacteria when lactose is present. The CAP site prevents the binding of RNA polymerase when glucose is present in the environment. The lacZ, lacY, and lacA genes code for proteins needed for lactose metabolism. Which is a scientific claim that is consistent with the information provided and Figure 1 ?
When bound to the operator, the repressor protein prevents lactose metabolism in E. coli.
A genetic counselor is consulted by a young man who is worried about developing Huntington's disease, an inherited disorder caused by a dominant allele of a single gene. The young man explains that his cousin was recently diagnosed with Huntington's disease, and the news has caused him to consider his own risk of developing the disorder. Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing Huntington's disease and transmitting it to his children?
Were your parents or grandparents ever diagnosed with Huntington's disease?
