Topic 17 Nucleotides

Question 1

Which of the following statements about nucleotides and nucleic acids are false? Select all that apply.
A. In RNA, the sugar group is deoxyribose
B. The nitrogenous base of a nucleotide is hydrophobic
C. Nucleotides join to form nucleic acids via peptide bonds
D. The sugar and phosphate groups of a nucleotide lie on the inside of the DNA helix
E. The two base pairs in DNA are adenine : thymine and cytosine : guanine

Answer 1

A. In RNA, the sugar group is deoxyribose
C. Nucleotides join to form nucleic acids via peptide bonds
D. The sugar and phosphate groups of a nucleotide lie on the inside of the DNA helix

Question 2

Which of the following sugars is found in DNA?
A. Glucose
B. Ribose
C. Fructose
D. Deoxyribose
E. Lactose

Answer 2

D. Deoxyribose

Question 3

Nucleotides have which of the following functions, in addition to being components of the nucleic acids DNA and RNA?
A. They transport cholesterol in the bloodstream
B. They act as a hormone, triggering the breakdown of glycogen to release glucose
C. They form a component of the cell membrane, and help to maintain its fluidity
D. They act as a store of energy to help power biochemical reactions

Answer 3

D. They act as a store of energy to help power biochemical reactions

Question 4

Which of the following nitrogenous bases occur in RNA? Select all that apply.
A. Adenine
B. Cytosine
C. Guanine
D. Uracil
E. Thymine

Answer 4

A. Adenine
B. Cytosine
C. Guanine
D. Uracil

Question 5

Which bases are the pyrimidine bases?

Answer 5

Cytosine, Thymine, Uracil

Question 6

Which bases are the purine bases?

Answer 6

Adenine, Guanine

Question 7

Which is more strongly bonded: G-C or A-T? Why?

Answer 7

G-C, 3 H-bonds instead of 2

Question 8

Tautomerism

Answer 8

any reaction that involves the simple intramolecular transfer of a proton

Question 9

Why is RNA more susceptible to hydrolysis?

Answer 9

Because of the hydroxyl group on the 2’ carbon