Biochemistry

Question 1

What are the 3 types of cell adhesion molecules (CAM)?

Answer 1

1. Gap junctions - cell to cell communication, transport of water
2. Tight junctions - prevent solutes from leaking
3. Desmosomes - connect cells

Question 2

Product of glycolysis

Answer 2

2 pyruvates

2 ATP 2 NADH

Question 3

5 enzymes of glycolysis

Answer 3

1. Hexokinase and glucokinase - irreversible - glucose > g6p
   - traps glucose in cell
   - inhibited by product
2. PFK - rate limiting - f6p > f16p
   - inhibited by ATP and glucagon
   - insulin stimulates PFK2, which converts f6p > f26p, which stimulates PFK1
3. G3PD - oxidation to g3p > 13biphosphoglycerate
4. 3phosphoglycerate kinase - substrate lvl phosphorylation
5. Pyruvate kinase - irreversible - later reaction of glycolysis - activated by f16p

Question 4

What is the key to fermentation?

Answer 4

Lactate dehydrogenase - oxidizes NADH to NAD+

Question 5

Important intermediates of glycolysis

Answer 5

1. DHAP - formed from f16biphosphate - converted to g3p then glycerol
2. 13BPG and PEP - used to generate ATP

Question 6

What decreases hemoglobins affinity for oxygen?

Answer 6

2,3-BPG

Question 7

Lactose

Answer 7

Galactose + glucose

Question 8

Alpha 1, 4 vs alpha 1, 6 bonds

Answer 8

Alpha 1, 6 bonds = branching

Question 9

What stimulates glycogen phosphorylase and what does it break down? What is it inhibited by?

Answer 9

Glucagon (liver) and AMP and epinephrine (skeletal muscle)
Alpha 1,4 bonds
ATP

Question 10

Pentode phosphate pathway

Answer 10

Production of NADPH (electron donor) and involves G6PD

Question 11

Ways to produce acetyl coA

Answer 11

Glycolysis - pyruvate dehydrogenase
Fatty acid oxidation
Amino acid catabolism - transamination
Ketones - when pyruvate dehydrogenase inhibited
Alcohol - coupled with NADH buildup, so acetyl coA used to make fatty acids

Question 12

Substrates of the citric acid cycle

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Answer 12

Pyruvate
Citrate
Isocitrate
Alpha-ketoglutarate
Succinyl-CoA
Succinate 
Fumarate
Malate
OAA

Question 13

Products of pyruvate dehydrogenase + CAC

Answer 13

4 NADH
1 FADH2
1 GTP
25 ATP per glucose
12.5 per pyruvate

Question 14

Checkpoints of CAC

Answer 14

1. Citrate synthase
2. Isocitrate dehydrogenase
3. Alpha ketoglutarate
   - ATP + NADH act as inhibitors (negative feedback)

Question 15

What promotes CAC?

Answer 15

High lols of ADP + NAD+

Question 16

How many complexes does the ETC have?

Answer 16

4

Question 17

How does OAA pass membranes?

Answer 17

Converted to malate

Question 18

Chemiosmotic coupling

Answer 18

Harnessing chemical energy of ETC to make ADP > ATP

-uses Fo, which acts as an ion channel

Question 19

Conformational coupling

Answer 19

F1 portion of ATP synthase spins to facilitate harnessing of gradient energy for ADP > ATP

Question 20

Regulation of oxidative phosphorylation

Answer 20

O2 and ADP

- NADH + FADH2 accumulate and inhibit CAC

Question 21

What breaks down of TGs in adipose?

Answer 21

Hormone sensitive lipase, which is stimulated by a drop in insulin or increased epinephrine and cortisol

Question 22

What breaks down chylomicrons and VLDL?

Answer 22

Lipoprotein lipase

Question 23

How are TGs and cholesterol transported in the blood?

Answer 23

Lipoproteins

Question 24

Rank the lipoproteins

Answer 24

Chylomicrons 
VLDL - made in liver - mainly TGs
IDL
LDL - mainly cholesterol
HDL - mainly cholesterol

Question 25

Apoprotein

Answer 25

Protein portion of lipoproteins

Receptor molecules

Question 26

Sources of cholesterol

Answer 26

LDL, HDL, citrate shuttle (acetyl CoA and ATP)

Question 27

What is the only FA that humans can synthesize?

Answer 27

Palmitic acid

Question 28

When and where does ketogenesis occur?

Answer 28

Excess acetyl CoA in the mitochondria of liver cells