AP bio exam tri 2MCQ

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype ccdd will be produced by the parents CcDd x CcDd

1/16

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype Rr will be produced by the parents Rr x rr

1/2

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype TTSs will be produced by the parents TTSs x TtSS

1/4

In a certain signal transduction pathway, the binding of an extracellular molecule to a cell-surface protein results in a rapid increase in the concentration of cyclic AMPAMP inside the cell. The cyclic AMPAMP binds to and activates cytosolic enzymes that then activate other enzymes in the cell. Which of the following statements best describes the role of cyclic AMPAMP in the signal transduction pathway?

It acts as a second messenger that helps relay and amplify the signal within the cell.

In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria. 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.

DNA replication occurs

during the S phase of the cell cycle

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype Aa will be produced by the parents Aa x Aa

1/2

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%

3'TAG TTC AAA CCG CGT AAC ATT 5'

5' AUC AAG UUU GGC GCA UUG UAA 3'

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. The probability that Matthew and Jane's first child will be an achondroplastic dwarf is

50%

In the following human pedigree, squares represent males, circles represent females, and shaded symbols indicate individuals affected with a disorder. 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 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 dogs, one pair of alleles determines coat color (dark and albino). Another pair of alleles determines hair length (short and long). Thus, each gamete will contain one of the coat-color alleles, C or c and one of the hair-length alleles, B or b. In repeated crosses of a specific dark, short-haired dog with an albino, long-haired dog, all the offspring were dark with short hair, as shown in cross I. However, in subsequent crosses of another dark, short-haired dog with a dark, long-haired dog, the ratios shown in cross II below were obtained. Which of the following is probably the genotype of the dark, short-haired parent in cross I?

CCBB

In dogs, one pair of alleles determines coat color (dark and albino). Another pair of alleles determines hair length (short and long). Thus, each gamete will contain one of the coat-color alleles, C or c and one of the hair-length alleles, B or b. In repeated crosses of a specific dark, short-haired dog with an albino, long-haired dog, all the offspring were dark with short hair, as shown in cross I. However, in subsequent crosses of another dark, short-haired dog with a dark, long-haired dog, the ratios shown in cross II below were obtained. In cross II, the genotype of the dark, short-haired parent is

CcBb

Enzyme used during replication to attach Okazaki fragments to each other

DNA ligase

Which of the following is most likely to create genetic variation in a population?

DNA polymerase errors during replication

Figure 1 illustrates a model of the molecules involved in DNA replication and their placement relative to each other. Figure 1. Model including molecules involved in DNA replication Which of the following correctly explains where DNA replication will begin on the strand oriented 5'→3', reading from left to right?

DNADNA replication will be initiated immediately to the left of the RNARNA, since DNADNA polymerase requires an RNARNA primer.

In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria. Plates that have only ampicillin-resistant bacteria growing include which of the following?

IV only

The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1. Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?

In involves enzymes activating other enzymes.

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 the structure and importance of plasmids to prokaryotes?

Plasmids are circular, double-stranded DNADNA molecules that provide genes that may aid in survival of the prokaryotic cell.

Restriction enzyme (E) Reverse transcriptase Enzyme used in the synthesis of mRNA

RNA polymerase

Enzyme used to position nucleotides during DNA replication

Restriction enzyme

Enzyme found in retroviruses that produce DNA from an RNA template

Reverse transcriptase

For following group of questions first study the description of the situation or data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. The diagram below illustrates the results of electrophoresis of DNA sequences obtained from a family of two adults and three children, and amplified using PCR. The bands represent short repeating sequences of variable length. Results for another female (X) are included for comparison. 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. Table 1. Nucleotide composition of sample DNA from selected organisms Which of the following statements best explains the data set?

Since the %A%A and the %T%T are approximately the same in each sample, adenine and thymine molecules must pair up in a double-stranded DNADNA 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.

In fruit flies, purple eyes and ebony body are traits that display autosomal recessive patterns of inheritance. In a genetics experiment, students cross wild-type flies with flies that have purple eyes and ebony bodies. The students observe that all the flies in the F1 generation have normal eyes and a normal body color. The students then allow the F1flies to mate and produce an F2 generation. The students record observations about the flies in the F2 generation and use the data to perform a chi-square goodness-of-fit test for a model of independent assortment. The setup for the students' chi-square goodness-of-fit test is presented in Table 1. Table 1. The students' chi-square goodness-of-fit test for a model of independent assortment PhenotypeObservedExpectedNormal eyes, normal body187171Normal eyes, ebony body4957Purple eyes, normal body4157Purple eyes, ebony body2719 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? A

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.

Antibiotics can be used to kill the specific pathogenic bacterium, Mycobacterium tuberculosis, that causes tuberculosis. The appearance of antibiotic-resistant strains has made it more difficult to cure M. tuberculosis infections. These antibiotic-resistant bacteria survive and pass on the genes to their offspring, making the resistant phenotype more common in the population. DNA analysis indicates that the genes for antibiotic resistance are not normally present in bacterial chromosomal DNA. 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.

Which of the following statements best describes how a growth factor stimulates cell division from outside a cell?

The growth factor binds to other cells in the same area and holds them together to form a large, multicellular structure.

In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria. Which of the following best explains why there is no growth on plate II?

The initial E. coli culture was not ampicillin-resistant.

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? 5'- GTT TGT CTG TGG TAC CAC GTG GAC TGA - 3'

The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point.

A series of crosses is performed with fruit flies (Drosophila melanogaster) to examine inheritance of the genes vestigial(vg) and cinnabar (cn). The recessive vg allele causes small, malformed wings called vestigial wings. The recessive cnallele causes bright-red eyes called cinnabar eyes. In the first cross, a female with wild-type wings and eyes is mated with a male with vestigial wings and cinnabar eyes. All the F1 individuals have wild-type wings and eyes. In the second cross, female F1 flies are mated with males with vestigial wings and cinnabar eyes. The phenotypes of 500 F2 individuals are shown in the table Which of the following is the most likely explanation of the results?

The two genes are linked on an autosome.

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.

In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria. Plates I and III were included in the experimental design in order to

demonstrate that the E. coli cultures were viable

For following group of questions first study the description of the situation or data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. The diagram below illustrates the results of electrophoresis of DNA sequences obtained from a family of two adults and three children, and amplified using PCR. The bands represent short repeating sequences of variable length. Results for another female (X) are included for comparison.

the mother cannot be the biological parent of all three children

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. 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

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.

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

In which of the following would there NOT be a change in the amino acid sequence of the peptide coded for by this DNA? 3'TAG TTC AAA CCG CGT AAC ATT 5'

Changing 3' AAA 5' to read 3' AAG 5'

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 Trp operator, preventing RNA polymerase from transcribing the operon.

Australian dragon lizards have a ZW sex-determination system. The male genotype is homogametic (ZZ), and the female genotype is heterogametic (ZW). However, all eggs incubated at temperatures above 32°C tend to develop into females. Which of the following best explains how the development of phenotypic female Australian dragon lizards with a ZZgenotype occurs when incubation temperatures are above 32°C?

Incubation temperatures above 32°C32°C inhibit the genes on the ZZ chromosome that produce proteins necessary for male development.

A model that represents a process occurring in a cell of a particular organism is shown in Figure 1. Figure 1. Process occurring in a cell Which of the following correctly explains the process shown in Figure 1 ?

Initiation of transcription is occurring because a strand of RNARNA is being produced from a DNADNAtemplate strand.

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. The genotypes of Matthew and Jane are best represented as

Matthe aa Jane Aa

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.

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.

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?

Figure 1 represents a metabolic process involving the regulation of lactose metabolism by E. coli bacteria. 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. Figure 1. Model of lac operon, comparing repressed and active states 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.