Biochem NTK for Final

Question 1

What’s the main purpose of mitochondrial CAP synthase?

Answer 1

Get rid of urea

Question 2

What does lipoprotein lipase do?

Answer 2

It hydrolyzes triglycerides in lipoproteins in chylomicrons and VLDLs into free FAs. It’s attached to the luminal surface of endothelial cells in capillaries.

Question 3

Lesch-Nyhan syndrome

Answer 3

No purine salvage from damaged HGPRT

Question 4

What does enhanced purine degradation lead to?

Answer 4

Urea and then gout

Question 5

Arginine, ornithine, etc, CAP, urea, kidneys

Answer 5

look this up

Question 6

What is used to treat hyperuricemia?

Answer 6

allopurinol (upregulates purine salvage via HGPRT)

Question 7

Hyperammonemia could be caused by problems w/ which of these enzymes:
glutamine synthetase, glutamate dehydrogenase, CAP synthetase 1, and/or branched-chain AA aminotransferase?

Answer 7

All except aminotransferase since they (the other three) all use NH4 as a substrate

Question 8

Disorders of nucleotide metabolism case what major problem?

Answer 8

SCIDS (sever combined immune deficiency syndrome)

Question 9

If you see elevated orotic acid levels, what should you think?

Answer 9

CAP build up, w/ a downstream bottleneck

Question 10

What does NAG synthase make?

Answer 10

It makes NAG, which allosterically activates CAP synthetase and glutaminase

Question 11

What is OTC?

Answer 11

It is the enzyme used to combine CAP and ornithine

Question 12

HGPRT: what is it used for?

Answer 12

Purine salvage

Question 13

What could be wrong in a pt. w/ hypoglycemia and normal lactic acid?

Answer 13

Hyperinsulinemia, defect in glycolysis, or defect in FA Ox.

Question 14

What molecule inhibits CPT 1 to prevent futile cycling?

Answer 14

Malonyl-CoA (from acetyl CoA)

Question 15

HMG-CoA Synthase is the RLS in ______

Answer 15

HMG-CoA Synthase is the RLS in ketone synthesis (in the liver!)

Question 16

HMG-CoA Reductase is the RLS in ______

Answer 16

HMG-CoA Reductase is the RLS in cholesterol synthesis

Question 17

What are the major differences between diabetic coma and “regulated” state of starvation?

Answer 17

Basal insulin, regulated pt. regulates FA and glycerol release, body fat and muscle proteins excreted out of urine for diabetic

Question 18

What are the three protein-metabolic molecule pairs we need to know?

Answer 18

alanine – pyruvate
glutamine – alphaketoglutarate
aspartate – OAA

Question 19

Why are MCTs special?

Answer 19

They don’t need the carnitine transport system to get into mitochondria

Question 20

What are the three main enzymes in the beta-Ox loop?

Answer 20

LCAD, MCAD, SCAD

Question 21

What are the two molecules formed by the carbons from beta ox?

Answer 21

acetyl-CoA and (in odd-chains) propionyl-CoA

Question 22

What is the common precursor for cholesterol synthesis and FA synthesis?

Answer 22

cytosolic acetyl-CoA

Question 23

Where is fat produced?

Answer 23

Only in the liver!!!

Question 24

What is the first ___DL created from excess glucose?

Answer 24

VLDLs

Question 25

What is the mnemonic for Apo proteins?

Answer 25

ApoA organizes HDL shell;
ApoB begins: assembly/secretion of chylomicrons/LDLs
ApoC collects: needed to deliver TGs to target tissues (it activates lipoprotein lipase)
ApoE exits: needed to exit circulation and for endocytosis by the liver.

Question 26

What is the necessary sign of a glycolysis defect?

Answer 26

Anemia

Question 27

What is the timeline for when various fuels are metabolized?

Answer 27

Ingested glucose: 0-4 hrs;
Glycogen starts at 4 hrs, peaks at 9, ends after 12;
FA Ox: starts at 6 hrs, plateaus at 2 days
GNG: starts at 10 hrs, plateaus at 2 days

Question 28

A pt. presents w/ renal loss of arginine. What are the metabolic affects of this disorder and how would you treat it?

Answer 28

Arginine splits into ornithine and urea. W/o it, urea cycle can’t function. CAP will accumulate, and the patient will become hyperammonemic (and basic).

Giving citrulline will help give some arginine supply.