Question 1

Which of the following correctly lists the three components of a nucleotide, the monomer of nucleic acids?

Accepted Answer

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

Question 2

Which of the following is a purine found in nucleic acids?

Accepted Answer

Adenine

Question 3

Which element is NOT commonly found in the structure of nucleic acids?

Accepted Answer

Sulfur

Question 4

Which functional group is present in every nucleotide and is responsible for linking nucleotides together in a nucleic acid polymer?

Accepted Answer

Phosphate group

Question 5

Which of the following best distinguishes DNA from RNA at the molecular level?

Accepted Answer

DNA contains deoxyribose sugar and thymine, while RNA contains ribose sugar and uracil.

Question 6

A scientist isolates a nucleic acid and determines that it contains the sugar ribose and the nitrogenous base uracil. Which type of nucleic acid is it?

Accepted Answer

RNA

Question 7

Which of the following formulas represents a purine base?

Accepted Answer

$$C_5H_4N_5$$

Question 8

If a nucleotide contains a deoxyribose sugar, a phosphate group, and the base cytosine, to which nucleic acid could it belong?

Accepted Answer

DNA

Question 9

Which of the following statements about pyrimidines is correct?

Accepted Answer

Pyrimidines have a single six-membered ring structure.

Question 10

A mutation replaces a purine with a pyrimidine in a DNA sequence. Which of the following best describes this type of mutation?

Accepted Answer

Transversion

Question 11

Which of the following best describes the backbone of a nucleic acid polymer?

Accepted Answer

A repeating pattern of sugar and phosphate groups

Question 12

Which of the following is a correct difference between the nitrogenous bases found in DNA and RNA?

Accepted Answer

DNA contains thymine, while RNA contains uracil.

Question 13

Which of the following best explains why nucleic acids are considered polymers?

Accepted Answer

They are made up of repeating nucleotide monomers joined by covalent bonds.

Question 14

Which of the following functional groups is found at the 5' end of a nucleic acid strand?

Accepted Answer

Phosphate group

Question 15

A biochemist is analyzing a molecule with the following structure: a five-carbon sugar, a phosphate group, and a nitrogenous base. Which class of biological molecule is this?

Accepted Answer

Nucleotide

Question 16

Which of the following best describes the difference in the sugars found in DNA and RNA?

Accepted Answer

DNA contains deoxyribose, which lacks an oxygen atom at the 2' carbon compared to ribose in RNA.

Question 17

Which of the following is a correct pairing of purines and pyrimidines in DNA?

Accepted Answer

Adenine pairs with thymine; guanine pairs with cytosine.

Question 18

Which of the following best describes the role of phosphodiester bonds in nucleic acids?

Accepted Answer

They link the 3' carbon of one sugar to the 5' phosphate of the next nucleotide.

Question 19

A researcher is comparing the chemical formulas of two nucleic acids. One contains $$C_5H_{10}O_4$ as its sugar, and the other contains C_5H$$_{10}$$O_5. $$Which statement is correct?

Accepted Answer

The nucleic acid with $$C_5H_{10}O_4$ is DNA, and the one with C_5H$$_{10}$$O_5 is $$RNA.

Question 20

Which of the following is a real-world application that relies on the structural differences between DNA and RNA?

Accepted Answer

Reverse transcription in retroviruses, where RNA is converted into DNA.

Nucleic Acids: Structure, Components, and Differences Between DNA and RNA

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