Nucleotide Metabolism

Question 1

Name all of the purines

Answer 1

Adenine and Guanine

Question 2

Name all of the Pyrimidines

Answer 2

Cytosine, Thymine, Uracil

Question 3

These high energy bonds link the 2nd and 3rd phosphate on a nucleoside triphosphate and drive many biochemical reactions

Answer 3

Anhydride bonds

Question 4

Ribose-5 Phosphate is derived from the _______ pathway.

Answer 4

HMP Shunt

Question 5

List the (+) and (-) regulators of PRPP synthetase.

Answer 5

(+) Activator = Inorganic Phosphate

(-) Inhibitor = Purine ribonucleotides

Question 6

PRPP has a pyrophosphate and a nitrogenous base attached at the _______.

Answer 6

Primary Carbon(1’)

Question 7

The rate limiting step in Purine nucleotide synthesis is catalyzed by _______.

Answer 7

PRPP Amidotransferase

Question 8

In Purine nucleotide synthesis, _______, ________, & ________ become part of the nitrogenous base in subsequent steps.

Answer 8

Glycine, Aspartate, and glutamine

Question 9

In Purine nucleotide synthesis, _____ is required for subsequent steps as a carbon donor.

Answer 9

Folate

Question 10

______ is required to make THF, the form in which folate is used.

Answer 10

Dihydrofolate reductase

Question 11

This drug will inhibit PRPP Amidotransferase similar to the inhibition by high levels of downstream products.

Answer 11

6-Mercaptopurine (Purine Analog)

Question 12

_____, a folic acid analog, is a common anti-tumor drug that inhibits _____, ultimately inhibiting nucleotide biosynthesis and rapidly dividing cells (common among anti-tumor drugs). It works especially in ________ cells.

Answer 12

Methotrexate, dihydrofolate reductase, mammalian.

Question 13

Sulfa drugs function as ________.

Answer 13

Antibiotics

Question 14

This family of drugs are:
Structural analogs of PABA

Competitive inhibitors of folic acid production in bacteria

Inhibitors of bacterial purine synthesis

(Think bacteria drugs)

Answer 14

Sulfonamides

Question 15

This is the rate limiting, committed step in pyrimidine synthesis…

Answer 15

CPS II - carbamoyl phosphate synthetase II

Question 16

What are the regulators of CPS II?

Answer 16

Activated (PRPP)

Inhibited (UTP)

Question 17

In pyrimidine synthesis, where is CPS II located in the cell?

Answer 17

Cytosol

Question 18

Once pyrimidine bases are produced, where are they attached?

Answer 18

To PRPP

Question 19

Ribonucleotides can be converted into deoxyribonucleotides by ___________

Answer 19

Ribonucleotide reductase

Question 20

______ is an anti-tumor drug that inhibits Ribonucleotide reductase.

(Also used to treat Sickle Cell Anemia as it promotes HbF synthesis)

Answer 20

Hydroxyurea

Question 21

Additional steps to convert dUMP into dTMP use _________.

Answer 21

Thymidylate synthase.

Question 22

Thymidylate synthase is inhibited an anti-tumor drug known as….

Answer 22

5-fluorouracil (5-FU)

Question 23

Hydroxyurea and 5-FU will affect ______ production, but not _________ production, so are especially good at targeting rapidly dividing cells.

Answer 23

1) DNA

2) RNA

Question 24

This class of antibiotic is selective for the prokaryotic version of dihydrofolate reductase.

Answer 24

Trimethoprim

Question 25

Humans must acquire _____ in the diet, whereas prokaryotes can synthesize their own.

(Hint: the usable form in humans is THF)

Answer 25

Folate

Question 26

Nucleotide Metabolism:

This condition results in patients being susceptible to almost any microorganism, requiring living in a sterile environment and is attributed to a deficiency in _________ in ____% of cases

Answer 26

SCID : severe combined immunodeficiency disease (the condition)

Adenosine deaminase deficiency

14% of cases

Question 27

In SCID, these 2 cell types of the immune system are majorly affected…

Answer 27

T-cells & B-cells

Question 28

The excretion pathway uses this intermediate ________, and this enzyme_______, which produces Uric acid, which is excreted in the _______.

Answer 28

Xanthine
Xanthine oxidase
Urine

Question 29

An accumulated amount of nucleotides may indicate a problem with the ______ cycle, which could potentially lead to the development of ______.

Answer 29

Excretion, gout

Question 30

This condition is indicative of elevated levels of Uric Acid in the blood…

Answer 30

Hyperuricemia

Question 31

Gout can be caused by:
Underexcretion of _______ (most common)

Which can be caused by poor _____ function, _______ imbalance, and certain drugs, etc.

Answer 31

Uric acid

Kidney, acid-base

Question 32

In over-producers of uric acid, this drug inhibits xanthine oxidase which produces uric acid.

Answer 32

Allopurinol

Question 33

This deficiency is X-linked and affects the purine salvage pathway. Caused by a defect in HGPRT and deficit of purines.

Answer 33

Lesch-Nyhan syndrome

Question 34

Hydroxyurea will inhibit the production of _________ ________.

Answer 34

Ribonucleotide reductase

Question 35

_______will inhibit the conversion of dUMP to dTMP which is used to RNA and DNA.

Answer 35

5-FU (5-fluorouracil)

Question 36

_________ bases are more complex to synthesize and so therefore about ____% of them are salvaged in the salvage pathway and ____% are excreted.

Answer 36

Purine
90%
10%

Question 37

______ _________ , which is responsible for the overproduction of uric acid, is the enzyme effected by allopurinol.

Answer 37

Xanthine oxidase