Question 1

Which of the following correctly describes the three components of a nucleotide?

Accepted Answer

Phosphate, ribose or deoxyribose sugar, nitrogen-containing base

Question 2

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

Accepted Answer

Glycosidic bond

Question 3

Which of the following molecules contains phosphoanhydride bonds?

Accepted Answer

Guanosine diphosphate (GDP)

Question 4

Which nitrogenous base is found only in RNA and not in DNA?

Accepted Answer

Uracil

Question 5

What is the structural difference between ribose and 2'-deoxyribose?

Accepted Answer

Ribose has a hydroxyl group at the 2' position, while 2'-deoxyribose has a hydrogen at the 2' position.

Question 6

Which of the following is a purine base found in both DNA and RNA?

Accepted Answer

Adenine

Question 7

What is the significance of the oxygen at the 2' position in ribose for RNA stability?

Accepted Answer

It decreases RNA stability by serving as a nucleophile for backbone cleavage.

Question 8

Which end of a DNA fragment generated by restriction enzyme digestion contains a phosphate group?

Accepted Answer

5' end

Question 9

During DNA polymerization, which direction do polymerases read the template strand?

Accepted Answer

3' to 5'

Question 10

Which of the following best explains why ATP is considered the energy currency of the cell?

Accepted Answer

ATP contains high-energy phosphoanhydride bonds that release energy upon hydrolysis.

Question 11

Which of the following is a correct pairing of DNA bases?

Accepted Answer

Adenine pairs with thymine

Question 12

What is the product of the alkaline hydrolysis of RNA?

Accepted Answer

A cyclic intermediate and cleavage of the phosphodiester backbone

Question 13

Which scientist(s) won the Nobel Prize for the discovery of restriction enzymes?

Accepted Answer

Werner Arber, Daniel Nathans, and Hamilton O. Smith

Question 14

Which of the following statements about phosphodiester bonds is correct?

Accepted Answer

They link the 3' hydroxyl of one nucleotide to the 5' phosphate of another.

Question 15

Which of the following is a consequence of the difference between ribose and deoxyribose in nucleic acids?

Accepted Answer

RNA is less stable than DNA because the 2' hydroxyl group can participate in nucleophilic attack.

Question 16

Which of the following is a pyrimidine base found in both DNA and RNA?

Accepted Answer

Cytosine

Question 17

What is the chemical formula for a phosphodiester bond between two nucleotides?

Accepted Answer

$$\mathrm{C_5$'-O-PO_2$-O-3'}$$

Question 18

Which of the following is true about the directionality of nucleic acid synthesis?

Accepted Answer

Polymerases synthesize nucleic acids in the 5' to 3' direction.

Question 19

Which of the following best describes the role of restriction endonucleases in molecular genetics?

Accepted Answer

They hydrolyze specific DNA sequences to generate fragments for genetic mapping.

Question 20

Which of the following equations represents the formation of a phosphoanhydride bond between two phosphoric acids?

Accepted Answer

$$\mathrm{H_3PO_4 + H_3PO_4 \rightarrow H_2P_2O_7 + H_2O}$$

Properties and Biological Roles of Nucleotides and Nucleic Acids

Study Guide - Practice Questions