Question 1

Which of the following best explains why sulfur and phosphorus were chosen as radioactive labels in the Hershey-Chase experiment?

Accepted Answer

Sulfur is found in proteins but not DNA, and phosphorus is found in DNA but not proteins.

Question 2

Which of the following statements about the structure of DNA is correct?

Accepted Answer

Adenine always pairs with thymine via hydrogen bonds.

Question 3

A mutation changes a DNA sequence from 5’-ATG GAA TGA-3’ to 5’-ATG GAA TAA-3’. What type of mutation has occurred, and what is the likely effect on the protein?

Accepted Answer

Nonsense mutation; the protein will be prematurely truncated.

Question 4

Which of the following best describes the outcome of the Meselson-Stahl experiment?

Accepted Answer

It provided evidence for the semiconservative model, where each daughter DNA molecule contains one old and one new strand.

Question 5

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA contains a poly-A tail, while RNA does not.

Question 6

A DNA strand has the sequence 5’-AGT CCA TGA-3’. What is the complementary DNA strand?

Accepted Answer

3’-TCA GGT ACT-5’

Question 7

Which enzyme is responsible for synthesizing short RNA primers during DNA replication?

Accepted Answer

Primase

Question 8

Why must a purine always pair with a pyrimidine in the DNA double helix?

Accepted Answer

To ensure the DNA molecule has a uniform diameter.

Question 9

Which of the following best describes the function of the 5’ cap and poly-A tail in eukaryotic mRNA?

Accepted Answer

They are required for the mRNA to exit the nucleus and protect it from degradation.

Question 10

A mutation occurs in the third position of a codon, but the amino acid sequence of the protein does not change. What is this type of mutation called?

Accepted Answer

Silent mutation

Question 11

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is degenerate, meaning multiple codons can code for the same amino acid.

Question 12

During translation, which site on the ribosome does the incoming aminoacyl-tRNA first bind?

Accepted Answer

A site

Question 13

Which of the following best describes the role of spliceosomes in eukaryotic cells?

Accepted Answer

They remove introns from pre-mRNA.

Question 14

A patient has a mutation in an intron of a gene. Which of the following is most likely?

Accepted Answer

The mutation will result in a silent mutation with no effect on the protein.

Question 15

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 16

Which of the following best explains why a frameshift mutation early in a gene is more likely to disrupt protein function than a point mutation late in the gene?

Accepted Answer

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

Question 17

Which of the following is a function of topoisomerase during DNA replication?

Accepted Answer

Prevents overwinding and relieves tension ahead of the replication fork.

Question 18

A scientist is analyzing a DNA sample and finds that 30% of the bases are adenine. According to Chargaff’s rules, what percentage of the bases should be cytosine?

Accepted Answer

$$20\%$$

Question 19

Which of the following best describes the direction in which DNA polymerase synthesizes new DNA?

Accepted Answer

It synthesizes DNA in the 5’ to 3’ direction.

Question 20

Which of the following is true about the process of alternative splicing?

Accepted Answer

It allows a single gene to code for multiple proteins.

BIO 1150 Exam 6 Study Guide – DNA, RNA, and Genetic Information

Study Guide - Practice Questions

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