Biochem - energy metabolism

Question 1

Fates of pyruvate

Answer 1

Pyruvate carboxylase -> oxaloacetate
Pyruvate dehydrogenase -> acetyl CoA -> TCA
Lactate dehydrogenase -> lactate -> cori cycle
Alanine

Question 2

Regulation of pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase

Answer 2

“TLC For Nobody”
Thiamine pyrophosphate (active B1)
Lipoid acid
Coenzyme A – vit B5
FAD – vit B 2
NAD + - vit B3

Question 3

Arsenic exposure

Answer 3

Inhibits lipoid acid
-> garlic breath
rice water stool

Question 4

Pyruvate dehydrogenase deficiency

Answer 4

• > lactate -> lactic acidosis
• > alanine – neuro defect

X linked congenital defet
Acquired – arsenic exposure
B vitamin def (B1)

Tx: vitamin supplementation
High fat diet
Ketogenic aa (lysine, leucine)

Question 5

Draw out TCA cycle key enzyme steps

Answer 5

Page 541

Question 6

Draw out electron transport chain w/ inhibition agents

Answer 6

Page 542

Question 7

Uncoupling agents acting on electron transport chain

Answer 7

Make inner mt membrane more permeable to H+ -> wasted energy -> heat

Thermogenic:
Brown fat
Hibernating animals in winter

High dose aspirin -> hyperthermic

2,4 dinitrophenol (2,4-DNP)

• wt loss – illegal
• > hyperthermia and death

Question 8

Draw cori cycle (lactate )

Answer 8

Page 542

Question 9

Draw out alanine cycle

Answer 9

Transamination and oxidative deamination involved in interorgan transport of nitrogen

Question 10

Major nitrogen carriers from tissues

Answer 10

Alanine
Glutamine

Excess nitrogen excreted as urea
Liver pulls N of O in glutamine and put N into urea cycle

Question 11

Enzymes catalyzing transamination reactions

Answer 11

Transaminase/aminotransferases transfer amino group from aa to alpha-ketoglutarate to form glutamate

Deaminated aa -> pyruvate for energy

Question 12

Draw out transaminases action

Answer 12

Page 543

Question 13

Cofactor required by all transaminases

Answer 13

Pyridoxal phosphate (vit B6 derivative)