Question 1

Which of the following best explains why telomeres pose a problem for DNA replication in eukaryotic cells?

Accepted Answer

DNA polymerase cannot fully replicate the 5' ends of linear chromosomes, leading to progressive shortening of telomeres.

Question 2

Which of the following statements correctly describes a key difference between DNA replication in bacteria and eukaryotes?

Accepted Answer

Eukaryotic DNA replication involves multiple origins of replication, whereas bacterial replication typically starts from a single origin.

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 4

Which of the following best describes the role of epigenetic modifications in cancer development?

Accepted Answer

Epigenetic changes can silence tumor suppressor genes or activate oncogenes without altering the DNA sequence.

Question 5

Which of the following is a key feature of Hardy-Weinberg equilibrium?

Accepted Answer

No mutation, migration, selection, or genetic drift occurs in the population.

Question 6

A researcher is studying a gene that is regulated by both enhancers and silencers. Which of the following best describes how these elements function?

Accepted Answer

Enhancers and silencers are DNA sequences that increase or decrease gene expression by binding specific transcription factors.

Question 7

Which of the following best explains why frameshift mutations often have more severe effects than point mutations?

Accepted Answer

Frameshift mutations alter the reading frame, potentially changing every amino acid downstream of the mutation.

Question 8

Which of the following is true regarding the difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In prokaryotes, transcription and translation are coupled, while in eukaryotes they are separated by the nuclear envelope.

Question 9

A population of 1000 individuals has the following genotype frequencies for a gene with two alleles, A and a: $$AA = 0.36$$, $$Aa = 0.48$$, $$aa = 0.16. Is $$this population in Hardy-Weinberg equilibrium?

Accepted Answer

Yes, because the observed genotype frequencies match the expected frequencies under Hardy-Weinberg equilibrium.

Question 10

Which of the following best describes the function of the CRISPR-Cas9 system in genetic engineering?

Accepted Answer

It is a targeted genome editing tool that can introduce double-strand breaks at specific DNA sequences.

Question 11

Which of the following statements about RNA interference (RNAi) is correct?

Accepted Answer

RNAi uses small RNA molecules such as siRNA to degrade specific mRNA, reducing gene expression.

Question 12

Which of the following is an example of a missense mutation?

Accepted Answer

A codon change from GAA (glutamic acid) to GUA (valine).

Question 13

Which of the following best describes the role of DNA methylation in gene regulation?

Accepted Answer

DNA methylation typically represses gene expression by preventing transcription factor binding.

Question 14

A geneticist is studying a quantitative trait in plants. Which of the following best explains why this trait shows continuous variation?

Accepted Answer

The trait is influenced by multiple genes and environmental factors.

Question 15

Which of the following is a key difference between transitions and transversions in DNA mutations?

Accepted Answer

Transitions involve purine to purine or pyrimidine to pyrimidine changes, while transversions involve purine to pyrimidine or vice versa.

Question 16

Which of the following best describes the function of a promoter in gene expression?

Accepted Answer

A promoter is a DNA sequence where RNA polymerase binds to initiate transcription.

Question 17

Which of the following is a real-world application of PCR (polymerase chain reaction)?

Accepted Answer

Amplifying DNA from a crime scene for forensic analysis.

Question 18

A patient is diagnosed with a cancer caused by a mutation in a tumor suppressor gene. Which of the following best explains how this mutation can lead to cancer?

Accepted Answer

The mutation inactivates the tumor suppressor gene, removing a critical brake on cell division.

Question 19

Which of the following best describes the difference between an enhancer and a silencer in gene regulation?

Accepted Answer

Enhancers increase transcription when bound by activators, while silencers decrease transcription when bound by repressors.

Question 20

Which of the following best explains why genetic drift has a greater effect in small populations?

Accepted Answer

Random changes in allele frequencies are more likely to significantly alter the gene pool in small populations.

Comprehensive Genetics Final Exam Study Guide

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