Unit 6 MCQ

Which of the following claims about the TYR, TRP2, and TRP1 mammalian genes is most likely to be accurate?

Which of the following claims about the TYR, TRP2, and TRP1 mammalian genes is most likely to be accurate?

The TYR, TRP2, and TRP1 genes may be located on different chromosomes but are activated by the same transcription factor.

Which of the following claims best explains why keratinocytes do not produce melanin?

Keratinocytes do not express the MITF gene.

Which of the following pieces of evidence would best support the researchers' claim above?

When researchers applied a drug that activates adenylyl cyclase to the mutant mice's ears, the level of melanin increased.

Based on the information provided in Figure 1 and Figure 2, which of the following best predicts the effects of a mutation in the promoter of the TYR gene that prevents it from being transcribed?

Skin pigmentation will not be able to change, resulting in a negative selection pressure.

Which of the following best explains a process occurring between point 1 and point 2 in Figure 3 ?

A poly‑A tail is added to RNA

Researchers discovered a mutant form of the TYR gene with a deletion of a single guanine nucleotide in the beginning of the coding sequence.

The mutation will change all subsequent amino acids in the TYR protein, leading to nonfunctional TYR protein. Individuals with this mutation will lack melanin in their hair, skin, and eyes and will not tan in response to UV radiation.

Which of the following statements best explains the experimental results observed in Figure 1 ?

E. coli in lane C have been successfully transformed and contain additional genetic information.

Which of the following best explains how the pattern of DNA arrangement in chromosomes could be used, in most cases, to determine if an organism was a prokaryote or a eukaryote?

Prokaryotic DNA - Single circular chromosome

Eukaryotic DNA - Multiple linear chromosomes

Which of the following best explains how the results should be interpreted?

The individual has an increased risk of developing colon cancer.

Given the results shown in Figure 1, which of the following correctly describes a relationship between the two species?

Species B has more short fragments of DNA than species A does

Which of the following best helps explain how the process represented in Figure 1 produces DNA molecules that are hybrids of the original and the newly synthesized strands?

Each newly synthesized strand remains associated with its template strand to form two copies of the original DNA molecule.

Which of the following graphs best predicts the data collected during the experiment?

D. Up, Medium, Up

Which of the following best predicts what will happen when a normal cell is exposed to a retrovirus?

The reverse transcriptase will produce DNA from the viral RNA, which can be incorporated into the host's genome and then transcribed and translated.

Figure 1. Model of damage to DNA caused by UV exposure

Which of the following statements best explains what is shown in Figure 1 ?

UV photons cause dimers to form, leading to misshapen DNA, which results in replication and transcription errors.

Which of the following evidence best supports a claim that tryptophan functions as a corepressor?

When trpR is mutated, the trp operon is transcribed regardless of tryptophan levels.

A cell needs to metabolize the substrate illustrated in Figure 1 for a vital cellular function. Which of the following best explains the long-term effect on the cell of splicing that yields only enzyme C mRNA?

The cell will die because it is unable to metabolize the substrate without enzyme A, which is structurally specific for the substrate shown

Which of the following statements best explains the role of Enzyme 1 in the DNA replication process?

Enzyme 1 is a topoisomerase that relieves tension in the overwound DNA in front of a replication fork.

Which of the following best supports the claim that binding of miRNA‑delta to the miRNA binding site inhibits translation of gene Q mRNA?

When the miRNA binding site sequence is altered, translation of Q mRNA occurs in the presence of miRNA-delta.

Which of the following statements provides the best explanation of the processes illustrated in Figure 1 ?

Sections of the pre-rRNA are removed, and the mature rRNA molecules are available to combine with proteins to form the ribosomal subunits.

A woman develops Huntington's disease. Her father had the disorder. Her mother did not, and there is no history of the disorder in the mother's family. Which of the following best explains how the woman inherited Huntington's disease?

She inherited an allele with more than 40 CAG repeats in the HTT gene from her father.

Which of the following best explains how this model illustrates DNA replication of both strands as a replication fork moves?

I is synthesized continuously in the 5′ to 3′ direction, and III is synthesized in segments in the 5′ to 3′ direction.

Which claim is most consistent with the information provided by the diagram and current scientific understanding of gene regulation and expression?

Some sequences of DNA can interact with regulatory proteins that control transcription.

Based on the information in Figure 1, which type of mutation explains the nature of the change in DNA that resulted in cystic fibrosis in the affected individual?

Deletion, because a thymine is missing, which changes the reading frame.

Nucleotide base pairing in DNA is universal across organisms. Each pair (T−A; C−G) consists of a purine and a pyrimidine. Which of the following best explains how the base pairs form?

Hydrogen bonds join a double-ringed structure to a single-ringed structure in each pair.