Question 1

Which experiment provided the first strong evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

Hershey and Chase's bacteriophage experiment

Question 2

Which of the following correctly describes the base-pairing rules in DNA?

Accepted Answer

$$A$$ pairs with $$T$$; $$C$$ pairs with $$G$$

Question 3

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

DNA helicase

Question 4

A mutation changes a codon from $$UAC to$$ $$UAA. $$What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 5

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

RNA contains uracil instead of thymine

Question 6

In eukaryotic cells, where does transcription occur and what is the main product?

Accepted Answer

Nucleus; mRNA

Question 7

Which of the following is an example of post-transcriptional gene regulation in eukaryotes?

Accepted Answer

Alternative splicing of pre-mRNA

Question 8

A scientist uses PCR to amplify a segment of DNA. Which of the following best describes the process?

Accepted Answer

PCR uses cycles of heating and cooling to denature DNA, anneal primers, and extend new strands with DNA polymerase.

Question 9

Which of the following best describes a genetically modified organism (GMO)?

Accepted Answer

An organism whose genome has been altered using recombinant DNA technology

Question 10

Which of the following is a function of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on codon-anticodon pairing.

Question 11

Which of the following best explains how epigenetic changes can affect gene expression without altering the DNA sequence?

Accepted Answer

Chemical modifications such as DNA methylation can silence or activate genes.

Question 12

In prokaryotes, what is the role of an operon in gene regulation?

Accepted Answer

It allows coordinated expression of multiple genes under a single promoter.

Question 13

A DNA sample is analyzed using gel electrophoresis. Which statement best describes how DNA fragments are separated?

Accepted Answer

Fragments are separated by size, with smaller fragments moving farther through the gel.

Question 14

Which of the following is a likely outcome of a frameshift mutation caused by a single nucleotide insertion?

Accepted Answer

All amino acids downstream of the mutation are changed, often resulting in a nonfunctional protein.

Question 15

Which process is responsible for converting the information in mRNA into a sequence of amino acids?

Accepted Answer

Translation

Question 16

Which of the following best describes the Sanger method for DNA sequencing?

Accepted Answer

It uses chain-terminating nucleotides to generate DNA fragments of varying lengths, which are then separated to determine the sequence.

Question 17

Which of the following is an example of how genomics can be applied in medicine?

Accepted Answer

Tailoring drug treatments based on a patient's genetic profile (pharmacogenomics)

Question 18

Which of the following statements about alternative splicing is correct?

Accepted Answer

It allows a single gene to code for multiple proteins by including or excluding different exons.

Question 19

A maize plant has been genetically modified to resist a specific insect pest. Which biotechnology tool was most likely used to insert the resistance gene into the maize genome?

Accepted Answer

Recombinant DNA technology

Question 20

Which of the following best describes the direction of new DNA strand synthesis during replication?

Accepted Answer

New DNA is synthesized in the $$5' to$$ $$3'$$ direction.

DNA, Gene Expression, Mutations, Gene Regulation, and Biotechnology: Study Guide

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