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Flashcards in Metabolism Deck (31):
1

Ethanol metabolism

Ethanol converted to acetaldehyde by alcohol dehydrogenase and NAD+
Acetaldehyde converted to acetate by acetaldehyde dehydrogenase and NAD+
NAD+ is limiting reagent

2

Metabolic changes seen as result of ethanol metabolism

Increased NADH/NAD+ ratio leads to:
-lactic acidosis
-fasting hypoglycemia
-hepatosteatosis

3

Fomepizole

Inhibits alcohol dehydrogenase. Used as antidote for methanol or ethylene glycol poisoning

4

Site of fatty acid sythesis

Acetyl coA produced in mitochondria; fatty acid synthesis occurs in cytosol

5

Site of ketogenesis

mitochondria

6

Metabolic processes that can happen in cytosol or mitochondria

Heme synthesis, urea cycle, gluconeogenesis

7

Mutase function

Relocates a functional group within a molecule

8

Difference between a kinase and a phosphorylase

Kinase uses ATP to add high energy phosphate. Phosphorylase adds inorganic phosphate without using ATP

9

Carbamoyl phosphate synthetases

I: rate limiting enzyme in urea cycle
II: rate limiting enzyme in de novo pyrimidine synthesis

10

Phosphofructokinase-1

Rate limiting enzyme in glycolysis

11

Fructose-1,6-bisphosphatase

Rate limiting enzyme in gluconeogenesis

12

Isocitrate dehydrogenase

Rate limiting enzyme in TCA cycle

13

Glycogen synthase

Rate limiting enzyme in glycogenesis

14

Glycogen phosphorylase

Rate limiting enzyme in glycogenolysis

15

G6PD

Rate limiting enzyme in HMP shunt

16

Glutamine phosphoribosylpyrophosphate amidotransferase

Rate limiting enzyme in de novo purine synthesis

17

Acetyl co-A carboxylase

rate limiting enzyme in fatty acid synthesis

18

canitine acetyltransferase I

rate limiting enzyme in fatty acid oxidation

19

HMG-CoA synthase

rate limiting enzyme in ketogenesis

20

NADPH function

Produced in HMP shunt. Used in anabolic processes, respiratory burst, cytochrome P450 system, and glutathione reductase

21

Hexokinase vs glucokinsae

Hexokinase: Used by most tissues to convert glucose to glucose-6-phosphate. Has high affinity but low capacity and is not affected by insulin

Glucokinase: Used by liver and beta cells of pancreas to convert glucose to glucose-6-phosphate. Has low affinity but high capacity and is induced by insulin so that excess glucose is stored in the liver in times of excess.

Either way, step requires ATP (carried out by kinase)

22

Pyruvate dehydrogenase complex

Converts pyruvate to acetyl coA using NAD+ as cofactor

23

Possible pathways for pyruvate

1) alanine
2) oxaloacetate: regenerate for TCA cycle, gluconeogenesis
3) acetyl coA: TCA cycle
4) lactate

24

Krebs cycle intermediates

Pneumonic: citrate is kreb's starting substrate for making oxaloacetate
-citrate
-isocitrate
-alpha-ketoglutarate
-succinyl coA
-succinate
-fumarate
-malate
-oxaloacetate

25

Classic Galactosemia

Impaired galactose-1-phosphate metabolism by galactose-1-phosphate uridyltransferase. Presents with vomiting, lethargy, and failure to thrive soon after breastfeeding begun

26

Anastrozole

Aromatase inhibitor

27

Galactokinase deficiency

Galacticol accumulates. Relatively mild. Galactose in blood and urine. Infantile cataracts, failure to track objects, failure to develop social smile.

28

Essential amino acids

Glucogenic: Met, Val, His
Glucogenic/ketogenic: Ile, Phe, Thr, Trp
Ketogenic: Leu, Lys

29

Acidic amino acids

Asp and Glu, neg charge at body pH

30

Basic amino acids

Arg, lys, his. No charge at body pH

31

Hyperammonemia

Excess NH4+ which depletes alpha-ketoglutarate, leading to inhibition of TCA cycle.

Treat by limiting protein and giving lactulose to acidify GI tract and trap NH4+ for excretion.