Question 1

Which of the following statements best describes the difference between DNA and RNA at the level of their sugar component?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 2

Which of the following bases is found only in RNA and not in DNA?

Accepted Answer

Uracil

Question 3

A nucleotide is composed of which of the following components?

Accepted Answer

A nitrogenous base, a pentose sugar, and a phosphate group

Question 4

Which property of nucleotides allows for their detection and quantification using spectrophotometry?

Accepted Answer

Their absorption of ultraviolet light around 260 nm

Question 5

What is the significance of tautomeric forms of nucleotide bases in DNA?

Accepted Answer

They can lead to mutations by altering base pairing properties.

Question 6

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

Accepted Answer

Topoisomerase

Question 7

According to Chargaff's rules, if a DNA molecule contains 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$20\%$

Question 8

Which of the following best describes the directionality of a DNA strand as conventionally written?

Accepted Answer

5' end to the left, 3' end to the right

Question 9

What is the distance between successive base pairs in the DNA double helix?

Accepted Answer

$0.34\ 	ext{nm}$

Question 10

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

Accepted Answer

B-form

Question 11

A researcher is using agarose gel electrophoresis to analyze DNA samples. Which DNA molecule will migrate fastest through the gel?

Accepted Answer

A supercoiled, compact DNA molecule

Question 12

Which of the following best explains why heating double-stranded DNA leads to denaturation?

Accepted Answer

Heat disrupts hydrogen bonds between complementary bases, separating the strands.

Question 13

Which of the following is a unique structural feature of telomeres in eukaryotic chromosomes?

Accepted Answer

They contain G-quadruplex structures.

Question 14

Which process describes the conversion of DNA-based information into messenger RNA?

Accepted Answer

Transcription

Question 15

A palindromic DNA sequence is most likely to form which of the following structures?

Accepted Answer

Hairpin or cruciform

Question 16

Which of the following best describes the role of DNA polymerase during replication?

Accepted Answer

It synthesizes new DNA strands using existing strands as templates.

Question 17

Which of the following is true regarding the secondary structure of nucleic acids?

Accepted Answer

It involves 3D arrangements such as the double helix.

Question 18

Which of the following best explains why most RNA molecules are single-stranded in cells?

Accepted Answer

RNA lacks complementary sequences for double helix formation except in regions of internal complementarity.

Question 19

Which of the following best describes the flow of genetic information in a typical cell?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 20

Which of the following is a property of the phosphate group in nucleotides at physiological pH?

Accepted Answer

It is negatively charged due to ionization.

Nucleic Acids: Structure, Properties, and Biological Functions

Study Guide - Practice Questions