Amino acids, proteins and enzymes

Question 1

Precursors of catecholamins

Answer 1

Phenylalanine and tyrosine

Question 2

Precursors of serotonin and niacin

Answer 2

Tryptophan

Question 3

Maple syrup urine disease related amino acids

Answer 3

Valine, leucine, and isoleucine

Question 4

Sites for O-linked glycosylation of proteins

Answer 4

Serine and threonine. Golgi

Question 5

Site for N-linked glycosylation of proteins

Answer 5

Asparagine. RE

Question 6

Nonpolar, Aliphatic Side Chains 6

Answer 6

Gly, ala, val, leu, Ile, Pro (GAVLIP)

Question 7

Aromatic Side Chains 3

Answer 7

Phe, Tyr, Trp

Question 8

Positively Charged R Groups 3

Answer 8

Lys, Arg, His (LAH)

Question 9

Negatively Charged R Groups 2

Answer 9

Asp, Glu

Question 10

Polar, Uncharged R Groups 6

Answer 10

Ser, Thr, Cys, Met, Asn, Gln (MAGSCT)

Question 11

Protein breakdown places

Answer 11

Lysosomal proteases, proteasomes.

Question 12

Essencial amino acids 10

Answer 12

Arginine* Methionine Histidine Phenylalanine Isoleucine Threonine Leucine Tryptophan Lysine Valine (PHITMALTVL)

Question 13

Negative nitrogen balance 5

Answer 13

Kwashiokor, dieatary deficiency, starvation, uncontrolled diebetes, infection

Question 14

Positive nitrogen balance 3

Answer 14

Growth, pregnacy, convalescence

Question 15

Convalescence

Answer 15

Recovery phase of injury or surgery

Question 16

∆G <0

Answer 16

thermodynamically spontaneous

Question 17

∆G >0

Answer 17

thermodynamically nonspontaneous

Question 18

∆G = 0

Answer 18

reaction at equilibrium

Question 19

∆G‡

Answer 19

energy of activation

Question 20

Michaelis-Menten Equation

Answer 20

V = Vmax [S] / Km + [S] and Vmax = k2 [E]

Question 21

Marasmus

Answer 21

Chronic deficiency of calories

Question 22

Competitive inhibitor

Answer 22

Increase of Km. Vmax no effect.

Question 23

Noncompetitive inhibitor

Answer 23

No effect of Km. Vmax decrease.

Question 24

Statin mechanism

Answer 24

Competitively inhibit 3-hydroxy-3-
methylglutaryl coenzyme A (HMG CoA)
reductase in cholesterol biosynthesis.

Question 25

Methotrexate mechanism

Answer 25

Competitively inhibits dihydrofolate
reductase, depriving the cell of
active folate needed for purine and
deoxythymidine synthesis, thus
interfering with DNA replication during
S phase.

Question 26

Allopurinol mechanism

Answer 26

Noncompetitively inhibits xanthine

oxidase.

Question 27

Methanol poisoning treatment

Answer 27

Methanol poisoning (wood alcohol
poisoning) is treated with ethanol
administration. Both are substrates
for alcohol dehydrogenase (ADH), with
ethanol having a much lower Km for
the enzyme compared with methanol.
This prevents methanol from being
converted to formaldehyde, which is
toxic and not metabolized further.