Question 1

Which of the following correctly describes the structural difference between DNA and RNA nucleotides?

Accepted Answer

DNA nucleotides have a deoxyribose sugar, while RNA nucleotides have a ribose sugar.

Question 2

Which base pairing is known as a Watson-Crick base pair in DNA?

Accepted Answer

$$A$$ pairs with $$T$$

Question 3

A phosphodiester bond in nucleic acids links:

Accepted Answer

The 3' carbon of one sugar to the 5' carbon of another sugar via a phosphate group.

Question 4

Which of the following is a minor base found in DNA that results from methylation?

Accepted Answer

5-methylcytosine

Question 5

What is the main biological function of DNA?

Accepted Answer

Carrying genetic information for protein synthesis and inheritance

Question 6

Which of the following statements about the double helix structure of DNA is CORRECT?

Accepted Answer

The two strands are antiparallel and the bases are stacked inside the helix.

Question 7

Which form of DNA is most commonly found in living cells under physiological conditions?

Accepted Answer

B-DNA

Question 8

What is the effect of methylation of cytosine in CpG sequences on DNA?

Accepted Answer

It increases the tendency of DNA to undergo mutations.

Question 9

Which of the following is TRUE regarding the hydrogen bonding in DNA base pairs?

Accepted Answer

$$A$$ and $$T$$ are connected by two hydrogen bonds, while $$G$$ and $$C$$ are connected by three hydrogen bonds.

Question 10

Which of the following is a function of messenger RNA (mRNA)?

Accepted Answer

Serves as a template for protein synthesis by conveying genetic information from DNA to ribosomes.

Question 11

A mutation that converts cytosine to uracil in DNA is most likely caused by which process?

Accepted Answer

Deamination

Question 12

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP stores and transfers chemical energy for cellular processes.

Question 13

Which of the following statements about the Sanger dideoxy method for DNA sequencing is CORRECT?

Accepted Answer

It relies on the incorporation of dideoxynucleotides to terminate DNA chain elongation.

Question 14

Which of the following is a consequence of depurination in DNA?

Accepted Answer

Loss of a purine base (adenine or guanine) from the DNA molecule.

Question 15

Which of the following is TRUE about the difference between eukaryotic and prokaryotic DNA?

Accepted Answer

Eukaryotic DNA is linear and found in the nucleus, while prokaryotic DNA is circular and found in the cytoplasm.

Question 16

Which of the following is a property of nucleotide bases that is important for DNA stability?

Accepted Answer

They are weakly basic and form hydrogen bonds that stabilize the double helix.

Question 17

Which of the following is a function of transfer RNA (tRNA)?

Accepted Answer

Carries amino acids to the ribosome during protein synthesis.

Question 18

Which of the following best explains why DNA is more stable than RNA under alkaline conditions?

Accepted Answer

DNA lacks a 2'-hydroxyl group, preventing base-catalyzed hydrolysis.

Question 19

Which of the following is TRUE about the major and minor grooves in the DNA double helix?

Accepted Answer

The major groove is wider and allows for protein binding and recognition.

Question 20

Which of the following is a consequence of UV light exposure on DNA?

Accepted Answer

Formation of thymine dimers, which distort the DNA helix.

Nucleotides and Nucleic Acids: Structure, Function, and Chemistry

Study Guide - Practice Questions