FC 1- Nucleotide Metabolism

Question 1

Nucleotide functions

Answer 1

• Structural component of: DNA and RNA
• Carriers of activated intermediates: ex: UDP-glucose in glycogen formation
• Structural component of several coenzymes (- CoA - NAD+, - FAD, NADP+)
• Energy “currency” of the cell (ATP)
• Regulators of many pathways (ie, ATP or AMP activating or inhibiting a pathway)

Question 2

Structure of Nucleotides

Answer 2

Features:

- Nitrogenous base
- Sugar

Question 3

Nitrogenous base

Answer 3

• Purines: Adenine and Guanine

- Pyrimidines: Cytosine, Thymine (DNA) and Uracil (RNA)

Question 4

Sugar:

Answer 4

• Ribose in RNA

- Deoxyribose in DNA

Question 5

Nucleoside

Answer 5

Nitrogenous base + Sugar

Question 6

Nucleotide

Answer 6

Nucleoside + 1-3 phosphate groups

Question 7

The anhydride bonds linking the 2nd and 3rd phosphate on a nucleoside triphosphate (ie, ATP, GTP) are

Answer 7

the high energy bonds driving many biochemical reactions

Question 8

Purine Nucleotide Synthesis

Answer 8

The ribose 5-phosphate is from the HMP shunt pathway

Question 9

Purine Nucleotide Synthesis

Step 1

Answer 9

PRPP synthetase catalyzes the formation of the activated pentose (Phosphoribosyl-pyrophosphate).
PRPP synthetase Regulation:
- activator: Inorganic phosphate
- inhibitor: purine ribonucleotides

Question 10

The pyrophosphate is attached at the

Answer 10

1’carbon, which is where the nitrogenous base will be attached

Question 11

Purine Nucleotide Synthesis

Default:

Answer 11

Default: production of ribonucleotides

If deoxyribonucleotides are needed, further steps will be taken