L18

Question 1

Tyrosine is a precursor for which 3 hormones?

Answer 1

Dopamine, norepinephrine, and epinephrine

Question 2

Glutamate is a precursor for which hormone?

Answer 2

GABA

Question 3

Histidine is a precursor for which hormone?

Answer 3

Histamine

Question 4

Tryptophan is a precursor for which hormone?

Answer 4

Serotonin

Question 5

By which mechanism do amino acids convert into hormones?

Answer 5

Decarboxylation and hydroxylation

Question 6

Galantamine is an alkaloid synthesized from which aa precursors? In which plant is it made?

Answer 6

Phe and Tyr. Daffodails

Question 7

Morphine is an alkaloid synthesized from which aa precursors? In which plant is it made?

Answer 7

Two Tyr. Poppies

Question 8

Cofactors for NT

Answer 8

Flavins, NADPH, NADH, and CoA

Question 9

Is NT breakdown a significant source of energy?

Answer 9

NO

Question 10

Difference between NT and nucleoside?

Answer 10

NT = pentose sugar + base + phosphate
Nucleoside = pentose sugar + base

Question 11

Which NT are the purines? How many rings?

Answer 11

A and G. 2 rings

Question 12

Which NT are the pyrimidines? How many rings?

Answer 12

T, C, and U. 1 ring

Question 13

Which are the main 3 aa involved in NT synthesis?

Answer 13

Asp, Gln, and Gly

Question 14

Which is the main reactant for NT synthesis?

Answer 14

Ribose 5-P

Question 15

Purines can be degraded into what?

Answer 15

Uric acid and ribose 1-P

Question 16

Pyrimidines can be degraded into what?

Answer 16

Ribose 1-P and malonyl-CoA

Question 17

What is the general pathway for making purines?

Answer 17

Pentose phosphate pathway -> ribose 5-P + ATP -> Phosphoribosylpyrophosphate (PRPP) -> IMP -> AMP and GMP

Question 18

What is the general pathway for making pyrimidines?

Answer 18

Pentose phosphate pathway -> ribose 5-P + ATP -> Phosphoribosylpyrophosphate (PRPP) -> Asp + carbamoyl-P -> UTP -> CTP

Question 19

Overall, from what are purines made?

Answer 19

2 formate, CO2, Gly, Asp, and Gln

Question 20

How is purine synthesis regulated?

Answer 20

Allosterically by ADP, AMP, GMP, and IMP

Question 21

How are NT monophosphates converted to NT triphosphates?

Answer 21

NT monophosphate kinases -> adenylate kinase -> guanylate kinase -> NT di-P kinase

Question 22

Which enzyme should be inhibited to prevent both purine and pyrimidine synthesis? What does it do?

Answer 22

PRPP synthetase, which normally converts ribose 5-P into PRPP

Question 23

Which enzyme should be inhibited to prevent purine synthesis but allow pyrimidine synthesis? What does it do?

Answer 23

Glutamine-PRPP amidotransferase, which normally converts PRPP into 5-Phosphoribosylamine

Question 24

Overall, from what are pyrimidines made? Ordering of synthesis?

Answer 24

Gln, Asp, and CO2. Pyrimidine ring formed first and then linked to PRPP

Question 25

How is pyrimidine synthesis regulated?

Answer 25

CTP end product inhibition CPSII inhibited by UTP, activated by ATP and PRPP OPR transferase stimulated by ATP Overall, pyrimidines inhibit pathway and purines stimulate it

Question 26

Describe the purine salvage/catabolism pathway

Answer 26

Salvage: GMP and AMP convert into guanine and hypoxanthine and react with PRPP through transferase to form GMP + PPi and IMP + PPi Catabolism: uric acid

Question 27

Describe the catabolism of pyrimidines

Answer 27

Broken down into urea via carbamoyl-P, malonyl-CoA , and CO2

Question 28

How does RNA convert to DNA?

Answer 28

Deoxy through ribonucleotide reductase. It uses NADPH as the electron donor. FAD is an electron acceptor/donor. NDP -> dNDP + water after reaction. Four subunits.

Question 29

How is ribonucleotide reductase regulated?

Answer 29

By many NT in order to balance ribo-NT vs deoxyribo-NT in body

Question 30

How is thymine made?

Answer 30

dUMP -> dTMP by folate thymidylate synthetase

Question 31

Which NT is targeted for chemotherapy and why? How is it targeted?

Answer 31

Thymine because cancer cells can't make DNA without it! Target dihydrofolate reductase