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 direction in which DNA polymerase synthesizes new DNA strands during replication?

Accepted Answer

5' to 3'

Question 3

A mutation changes the DNA sequence from $$	ext{TAC} to$$ $$	ext{TAA} in a $$gene. If $$	ext{TAC}$$ codes for methionine and $$	ext{TAA} is a $$stop codon, what type of mutation has occurred?

Accepted Answer

Nonsense mutation

Question 4

Which of the following best explains why RNA contains uracil instead of thymine?

Accepted Answer

Uracil is structurally similar to thymine but is less energy-intensive to produce, and RNA is typically short-lived.

Question 5

During transcription in eukaryotes, which of the following sequences of events is correct?

Accepted Answer

Initiation → Elongation → Termination

Question 6

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

DNA helicase

Question 7

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

Accepted Answer

Denaturation, annealing, extension

Question 8

Which of the following statements about the epigenome is TRUE?

Accepted Answer

The epigenome consists of chemical modifications to DNA and histones that affect gene expression without changing the DNA sequence.

Question 9

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon.

Question 10

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

Accepted Answer

Alternative splicing of pre-mRNA

Question 11

A researcher is using gel electrophoresis to analyze DNA fragments. Which property of DNA allows this technique to separate fragments by size?

Accepted Answer

DNA fragments are negatively charged and move toward the positive electrode, with smaller fragments moving faster through the gel matrix.

Question 12

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

Accepted Answer

An organism whose genome has been altered using recombinant DNA technology to include genes from another species or modified versions of its own genes.

Question 13

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

Accepted Answer

A change in the reading frame, resulting in a completely different amino acid sequence downstream of the mutation.

Question 14

Which of the following statements about the Sanger method of DNA sequencing is correct?

Accepted Answer

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

Question 15

Which of the following best explains how pharmacogenomics can improve medical treatments?

Accepted Answer

By analyzing a patient's genome, doctors can tailor drug treatments to maximize effectiveness and minimize side effects.

Question 16

Which of the following is a key difference between prokaryotic and eukaryotic gene regulation?

Accepted Answer

Prokaryotes often use operons to regulate groups of genes, while eukaryotes use transcription factors to regulate individual genes.

Question 17

A maize plant has been genetically modified to resist a specific insect pest. Which biotechnology tool was most likely used to confirm the presence of the inserted gene in the plant's genome?

Accepted Answer

Southern blotting

Question 18

Which of the following best describes the role of miRNAs in gene regulation?

Accepted Answer

They bind to complementary mRNA sequences and can block translation or lead to mRNA degradation.

Question 19

A DNA sequence is transcribed into the mRNA sequence $$	ext{AUG GCU UAA}. $$Using the genetic code, what is the resulting amino acid sequence?

Accepted Answer

Methionine - Alanine

Question 20

Which of the following best explains why alternative splicing increases protein diversity in eukaryotes?

Accepted Answer

It allows a single gene to produce multiple mRNA variants by including or excluding different exons.

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

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