Biochem-Metabolism Flashcards Preview

USMLE Step 1-2015 > Biochem-Metabolism > Flashcards

Flashcards in Biochem-Metabolism Deck (116)
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1

Mitochondria as metabolism site:

Fatty acid oxidation (B-oxidation), acteyl-coA production, TCA cycle, ketogenesis, oxidative phosphorylation (FAT KOP thought he was MITO)

2

Cytoplasm as metabolism site:

HMP shunt, glycolysis, steroid synthesis, protein synthesis, cholesterol synthesis

3

Both cytoplasm and mitochondria for metabolism?

Heme synthesis, Urea cycle, Gluconeogenesis (HUGs take two (i.e. both))

4

Process: Glycolysis
Rate limiting enzyme?
Regulators + and -

Phosphofructokinase-1 (PFK-1)
+AMP, fructose 2,6-biphosphate
-ATP, citrate

5

Process: Gluconeogenesis
Rate limiting enzyme?
Regulators + and -

Frustose-1,6,-bisphosphatase
+ ATP, acetyl-coA
-AMP, fructose 2,6-bisphosphate

6

Process: TCA cycle
Rate limiting enzyme
Regulators + and -

Isocitrate dehydrogenase
+ ADP
- ATP, NADH

7

Process: Glycogenesis
Rate limiting enzyme?
+ and - regulators

Glycogen synthase
+ Glucose-6-phosphate, insulin, cortisol
- Epinephrine, glucagon

8

Process: Glycogenolysis
Rate limiting enzyme?
+ and - regulators

Glycogen phosphorylase
+ Epinephrine, glucagon, AMP
-Glucose-6-phosphate, insulin, ATP

9

HMP shunt
Rate limiting enzyme
+ and - regulators

Glucose-6-phosphate dehydrogenase (G6PD)
+ NADP+
- NADPH

10

De novo pyrimidine synthesis
Rate limiting enzyme
+ and - regulator

CPS II
+ATP
-UTP

11

De novo purine synthesis
Rate limiting enzyme
+ and - regulator

Glutamine-PRPP-amidotransferase
-AMP, IMP, GMP

12

Urea cycle
Rate limiting enzyme
+ and - regulator

Carbomoyl phosphate synthetase I
+ N-acetylglutamate

13

Fatty acid synthesis
Rate limiting enzyme
+ and - regulator

Acetyl-CoA carboxylase
+ insulin, citrate
- glucagon, palmitoyl-CoA

14

Fatty acid oxidation
Rate limiting enzyme
+ and - regulator

Carnitine acyltrnasferase I
- malonyl-coA

15

Ketogenesis
Rate limiting enzyme
+ and - regulator

HMG-CoA synthase

16

Cholesterol synthesis
Rate limiting enzyme
+ and - regulator

+ Insulin, thyroxine
- glucagon, cholesterol

17

What monosaccharide is metabolized the fastest and why?

Fructose because it enters glycolysis after PFK-1 (a potent regulator of glycolysis)

18

What toxin causes glycolysis to produce zero net ATP?

Arsenic

19

Aerobic metabolism in heart/liver ATP production

32 ATP via malate/aspartate shuttle

20

Anaerobic metabolism in muscle ATP production

30 ATP via glycerol 3 phosphate shuttel

21

Universal electron acceptors?

NAD+, NADP+, FAD+

22

NAD+ is generally used in _____

Catabolic processes carry reducing equivalents away as NADH

23

NADPH generally used in?
What is it a producut of?

-Anabolic processes, respiratory burst, cyp450, glutathione reductase
-HMP shunt

24

Negative feedback on glucokinase production?

Fructose-6-phosphate

25

Negative feedback on hexokinase production?

Glucose-6-phosphate

26

Garlic breath, vomiting, rice-water stools

Arsenic poisoning

27

PDH complex and alphaketoglutarate dehydrogenase complex require what 5 same cofactors?

pyrophosphate (B1, thimaine;Tpp), Lipoic acid, CoA (B5, pantothenic acid), NAD (B3, niacin), FAD (B2, riboflavin)-->Tender Loving Care For Nobody

28

PDH complex is activated by exercise and how is it acvitvated?

Increase NAD+/NADH, Increase Calcium, Increase ADP

29

High Fructose 2,6 BP has what affect on alanine?

Prevents conversion of pyruvate to alanine in muscle and transport over to liver where it is converted back to pyruvate for use in gluconeogenesis (i.e. gluconeogenic conversion of alanine to glucose)

30

Only purely ketogenic amino acids

Lysine and leucine