Question 1

Which of the following is NOT a component of a nucleotide as depicted in the study material?

Accepted Answer

A carboxyl group

Question 2

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

Accepted Answer

Uracil

Question 3

What is the primary difference between a nucleoside and a nucleotide?

Accepted Answer

Nucleotides contain a phosphate group; nucleosides do not.

Question 4

Which of the following correctly matches the base with its structure as shown in the study material?

Accepted Answer

Guanine: Purine

Question 5

In the carbon numbering system of nucleotides, which carbon of the pentose sugar is attached to the nitrogenous base?

Accepted Answer

$$1'$$

Question 6

Which of the following statements about nucleotide triphosphates is correct according to the study material?

Accepted Answer

They are used to provide energy for nucleic acid synthesis.

Question 7

A mutation replaces thymine with uracil in a DNA molecule. What is the most likely consequence?

Accepted Answer

The DNA may be recognized as damaged and repaired.

Question 8

Which base pairing is correct according to the structures shown in the study material?

Accepted Answer

Cytosine pairs with Guanine

Question 9

If a nucleotide lacks a phosphate group, what is it called?

Accepted Answer

Nucleoside

Question 10

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

Accepted Answer

Cytosine

Question 11

During DNA synthesis, which end of the nucleotide chain is extended?

Accepted Answer

$$3'$$ end

Question 12

Which of the following is NOT a function of nucleotide triphosphates?

Accepted Answer

Acting as enzymes in metabolic reactions

Question 13

Which of the following correctly describes the difference between purines and pyrimidines?

Accepted Answer

Purines have a double ring structure; pyrimidines have a single ring.

Question 14

Which base is NOT present in RNA?

Accepted Answer

Thymine

Question 15

A scientist is analyzing a nucleic acid sample and finds the following base composition: 30% adenine, 30% thymine, 20% guanine, and 20% cytosine. What type of nucleic acid is this most likely to be?

Accepted Answer

Double-stranded DNA

Question 16

Which carbon of the pentose sugar is bonded to the phosphate group in a nucleotide?

Accepted Answer

$$5'$$

Question 17

Which of the following is a correct statement about the structure of nucleic acids?

Accepted Answer

Nucleic acids are polymers of nucleotides.

Question 18

Which of the following bases is a purine?

Accepted Answer

Guanine

Question 19

If a DNA molecule contains 20% cytosine, what percentage of guanine does it contain?

Accepted Answer

20%

Question 20

Which of the following is true regarding the role of nucleotides in cellular metabolism?

Accepted Answer

Nucleotide triphosphates provide energy for biosynthetic reactions.

Nucleic Acids: Structure and Components

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