$5'\text{-}A\text{-}C\text{-}G\text{-}T\text{-}T\text{-}3'$

Question 1

Which of the following statements correctly describes the difference between DNA and RNA at the sugar level?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 2

Which base is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 3

What type of bond connects the base to the sugar in a nucleoside?

Accepted Answer

Glycosidic bond

Question 4

Which of the following is a correct representation of the primary structure of a nucleic acid?

Accepted Answer

$5'	ext{-}A	ext{-}C	ext{-}G	ext{-}T	ext{-}T	ext{-}3'$

Question 5

Which experiment provided definitive evidence that DNA replicates semiconservatively?

Accepted Answer

Meselson-Stahl experiment

Question 6

What is the main reason why DNA is more stable than RNA under alkaline conditions?

Accepted Answer

DNA lacks a 2' hydroxyl group, preventing cyclic intermediate formation.

Question 7

Which of the following correctly describes the base pairing in DNA according to Chargaff's rules?

Accepted Answer

$\%A = \%T$ and $\%G = \%C$

Question 8

During DNA denaturation, which of the following changes occurs?

Accepted Answer

The DNA absorbs more ultraviolet light.

Question 9

Which of the following is NOT a function of nucleic acids in cells?

Accepted Answer

Catalysis of metabolic reactions

Question 10

Which enzyme is responsible for relieving supercoiling in DNA during replication?

Accepted Answer

Topoisomerase

Question 11

A DNA molecule is found to have 20% adenine. What is the percentage of guanine in this molecule?

Accepted Answer

30%

Question 12

Which of the following best explains why high ionic strength stabilizes the DNA duplex?

Accepted Answer

It neutralizes the negative charges on phosphate groups, reducing electrostatic repulsion.

Question 13

Which of the following is a correct description of the flow of genetic information in a cell?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 14

Which of the following is a property of nucleotides that allows their detection and quantification in solution?

Accepted Answer

They absorb ultraviolet light.

Question 15

Which of the following statements about the DNA double helix is correct?

Accepted Answer

The two strands are antiparallel.

Question 16

Which of the following is a direct result of the cooperative nature of the helix-to-coil transition in DNA denaturation?

Accepted Answer

Denaturation occurs abruptly over a narrow temperature range.

Question 17

Which of the following techniques is commonly used to amplify a specific DNA sequence in vitro?

Accepted Answer

Polymerase chain reaction (PCR)

Question 18

Which of the following is true about the tautomerization of purine and pyrimidine bases?

Accepted Answer

It can lead to mutations during DNA replication.

Question 19

Which of the following is a key difference between B-form and A-form DNA?

Accepted Answer

A-form DNA is more compact than B-form DNA.

Question 20

Which of the following is a correct description of the process of site-directed mutagenesis?

Accepted Answer

It uses a mismatched synthetic nucleotide primer to introduce a mutation into a gene.

Nucleic Acids: Structure, Properties, and Biological Functions

Study Guide - Practice Questions