Biochemistry Flashcards Preview

MCAT > Biochemistry > Flashcards

Flashcards in Biochemistry Deck (28):
1

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

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

2

Product of glycolysis

2 pyruvates
2 ATP 2 NADH

3

5 enzymes of glycolysis

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

4

What is the key to fermentation?

Lactate dehydrogenase - oxidizes NADH to NAD+

5

Important intermediates of glycolysis

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

6

What decreases hemoglobins affinity for oxygen?

2,3-BPG

7

Lactose

Galactose + glucose

8

Alpha 1, 4 vs alpha 1, 6 bonds

Alpha 1, 6 bonds = branching

9

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

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

10

Pentode phosphate pathway

Production of NADPH (electron donor) and involves G6PD

11

Ways to produce acetyl coA

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

12

Substrates of the citric acid cycle

Please Can I Keep Selling Seashells For Money Officer?

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

13

Products of pyruvate dehydrogenase + CAC

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

14

Checkpoints of CAC

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

15

What promotes CAC?

High lols of ADP + NAD+

16

How many complexes does the ETC have?

4

17

How does OAA pass membranes?

Converted to malate

18

Chemiosmotic coupling

Harnessing chemical energy of ETC to make ADP > ATP
-uses Fo, which acts as an ion channel

19

Conformational coupling

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

20

Regulation of oxidative phosphorylation

O2 and ADP
- NADH + FADH2 accumulate and inhibit CAC

21

What breaks down of TGs in adipose?

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

22

What breaks down chylomicrons and VLDL?

Lipoprotein lipase

23

How are TGs and cholesterol transported in the blood?

Lipoproteins

24

Rank the lipoproteins

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

25

Apoprotein

Protein portion of lipoproteins
Receptor molecules

26

Sources of cholesterol

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

27

What is the only FA that humans can synthesize?

Palmitic acid

28

When and where does ketogenesis occur?

Excess acetyl CoA in the mitochondria of liver cells