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Flashcards in Metabolism Deck (44)
1

What is fomepizole

Antidote for alcohol poisoning
It inhibits alcohol dehydrogenase

2

What is disulfiram

Inhibits acetaldehyde dehydrogenase causing acetylaldehyde to accumulate making the patient feel hungover.

Treats alcoholism.

3

What does alcohol metabolism depend on?

Depends mostly on NAD + being converted to NADH

4

Phosphofructokinase 1

rate determening enzyme for glycolysis

5

Fructose - 1,6 bisphosphatase

Rate limiting enzyme for gluconeofenesis

6

Isocitrate dehydrogenase

TCA cycle rate limiting enzyme

7

Glycogen synthase

Glycogenesis Rate limiting enzyme

8

Glycogen phosphorylase

Glycogenolysis RLE

9

Glucose 6 phosphate dehydrogenase

HMP Shunt RLE
Important for NADPH formation

10

Carbamoyl phosphate synthetase II

De novo pyrimidine synthesis RLE

11

Glutamine-phosphoribosylpyrophosphate amidotransferase (PRPP)

De nobo purine synthesis RLE

12

Carbamoyl phosphate synthetase I

Urea cycle RLE

13

Acetyl-CoA carboxylase

Fatty acid synthesis RLE

14

Carnitine acyltransferase I

Fatty acid oxidation RLE

15

HMG-CoA synthase

Ketogenesis RLE

16

HMG-CoA Reductase

Cholesterol synthesis RLE

17

First enzyme in the TCA?

Citrate synthase takes Acetyl-CoA to make isocitrate.

18

Outside sourcs of odd chain fatty acids, branched chain amino acids, and methionine can enter the TCa through what form?

Succinyl CoA

19

the urea cycle can input into the TCA through which form?

Through fumarate formation.
At the expense of also creating urea.

20

what enzyme is specifically inhibited by Arsenic?

Lipoic acid resulting in vomiting, rice water stools, and garlic breath.

Patient is unable to link glycolysis and TCA cycle through mitochondria.

21

what molecule does the TCA utilize in its formation of products?

Utilizes Acetyl-Coa to create NADH, FADH, CO2 and GTP`

22

What is the starting substrate of the TCA?

Citrate.
Ends as oxaloacetate.

23

which steps of the TCA create NADH?

Isocitrate from citate

Succinyl coa from isocitrate
Oxaloacetate from malate

24

Which part of the TCA results in FADH2 formation?

Succinate to fumarate

25

Which part of the TCA results in GTP formation?

Succinyl CoA to succinate reaction.

26

what does the HMP shunt do?

Excess glucose -6- p can be funneled into this pathway to promote NADPH creation.

Also gives ribose for nucleotide synthesis.

27

What role does glucose 6 phosphate dehydrogenase deficiency entail?

NADPH is necessary to keep glutathione reduced which in turn detoxifies free radicals and peroxides.

Decreased NADPH in RBC's leads to hemolytic anemia. Fava beans and sulfonamides can really ramp this up.

Look for heinz bodies (denatured hemoglobin) and bite cells

28

fructose intolerance

Deficiency in aldolase B
Fructose - 1 - phosphate accumulates causing a deficiency in phosphate.

Look for flare ups after drinking juice and presence of fructose in the urine.

29

What is required for fatty acid synthesis?

Citrate transport from the mitochondria to the cytosol.
Mostly in the liver and lactating mamary glands/ fat tissue.

30

What is required for for long chain fatty acid degradation?

Requires carnitine dependent transport into the mitochondral matrix

31

What happens in a carnitine deficiency?

Inherited defect in transport of long chain fatty acids into the mitochondra.

Toxic accumulation leading to weakness, hypotonia, and hypoketoic hypoglycemia.

32

How are ketone bodies created?

In the liver, fatty acids and amino acids are metabolized to acetoacetate and beta hydroxybutyrate.

In prolonged starvation, and diabetic ketoacidosis, oxaloacetate is depleted for gluconeogenesis.

33

How man calories in...
1g protein
1g carbohydrate
1g fat
1g alcohol

carbs and protein have 4 kcals
fat has 9kcal
1g alcohol has 7kcal

34

How is cholesterol synthesized?

Cholesterol needed to maintain cell membrane integrity and to synthesize bile acid, steroids and vitamin D.

Rate limiting enzyme is HMG-CoA

35

What does HMG-CoA do?

Insulin acts on it to convert HMG-CoA to mevalonate. this occurs in the synthesis of cholesterol.

statins actively inhibit this bad boy

36

Hormone sensitive lipase

Degradation of triglyerides stored in adipocytes

37

Hepatic triglyceride lipase

degradation of triglycerides remaining in IDL

38

What does lipoprotein lipase do?

LPL degrades TGs corculating in chylomicrons and VLDLs and is found on vascular endothelial cell surfaces.

39

What does LCAT do?

Esterfies cholestero to be carried in HDL

40

What is the purpose of apo protein B-48 and B100?

B48 mediates chylomicron secretion
B-100 binds the LDL receptor at the liver.

41

Which lipoproteins carry the most cholesterol?

Lipoproteins LDL and HDL

42

Hyperchylomicronemia

Lacks LPL
Thus excessive chylomicrons, TG and cholesterol floating in blood.

Causes pancreatitis and hepatosplenomegaly

43

Familial hypercholesterolemia

Increased LDL and cholesterol

Defected LDL receptors
Causes accelerated atherosclerosis

44

Hypertriglyceridemia

Hepatic overproduction of VLDL
Causes hypertriglyceridemia that can lead to pancreatitis.

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