MITSOURA Q's [PDH & TCA Cycle & Their Regulation, ETC & Oxidative Phosphorylation, Oxygen Toxicity & Oxidative Stress]

Question 1

what are the 3 symptoms of niacin deficiency?

Answer 1

dermatitis, diarrhea, dementia

Question 2

what are the symptoms of riboflavin deficiency?

Answer 2

dermatitis, cheiliosis, glossitis

Question 3

[HIGH YIELD] which cofactor does E1 of PDH require?

Answer 3

thiamine pyrophosphate (TPP) factor

Question 4

[HIGH YIELD] which cofactor does E2 of PDH require?

Answer 4

lipoid acid cofactor (target of arsenic poisoning) & CoA cofactor

Question 5

[HIGH YIELD] which cofactor does E3 of PDH require?

Answer 5

FAD & NAD+ cofactors

Question 6

[HIGH YIELD] what are the 5 cofactors of PDH?

Answer 6

• TPP, lipoid acid, FAD

- diffusible: NAD+, CoA

Question 7

what are the common symptoms of PDH deficiency?

Answer 7

lactic acidosis and neurological symptoms

Question 8

what are the treatments for PDH deficiency?

Answer 8

• ketogenic diet (low carbohydrate/high fat)
• thiamine administration
• muscle relaxants & anti-convulsants

Question 9

which diseases does thiamine (vitamin B1) deficiency cause?

Answer 9

Beriberi, Wernicke encephalopathy, Korsakoff syndrome, Wernicke-Korsakoff syndrome

Question 10

[HIGH YIELD] which enzymes does thiamine (vitamin B1) deficiency affect?

Answer 10

PDH, HMP, alpha-ketoglutarate dehydrogenate

Question 11

wet Beriberi

Answer 11

edema, cardiovascular symptoms (cardiac failure)

Question 12

dry Beriberi

Answer 12

peripheral neurologic dysfunction

Question 13

Wernicke encephalopathy

Answer 13

REVERSIBLE

-ataxia, confusion, nystagmus

Question 14

Korsakoff syndrome

Answer 14

IRREVERSIBLE

-deficits in memory, hallucinations

Question 15

[HIGH YIELD] what are the 5 cofactors of alpha-ketoglutarate dehydrogenase?

Answer 15

same as PDH:

-TPP, lipoid acid, FAD, NAD+, CoA

Question 16

[HIGH YIELD] what is the energy production of the TCA cycle (for full turn of ONE pyruvate)?

Answer 16

1 GTP, 3 NADH, 1 FADH2

Question 17

[HIGH YIELD] what is the energy production of the TCA cycle (for full turn of ONE glucose)?

Answer 17

2 GTP, 6 NADH, 2 FADH2

Question 18

where does TCA cycle occur?

Answer 18

mitochondria

Question 19

oxidation

Answer 19

loss of electrons

Question 20

reduction

Answer 20

gain of electrons

Question 21

what kind of rxn does dehydrogenase carry out?

Answer 21

redox rxn

Question 22

what are the biologically active forms of niacin/nicotinic acid (vitamin B3)?

Answer 22

NAD+ & NADP+

Question 23

what do you call niacin deficiency?

Answer 23

pellagra

Question 24

prosthetic group

Answer 24

permanently attached to enzymes

Question 25

examples of prosthetic groups

Answer 25

TPP, lipoid acid, FAD

Question 26

what are the biologically active forms of riboflavin (vitamin B2)?

Answer 26

FAD & FMN

Question 27

what do you call riboflavin deficiency?

Answer 27

ariboflavinosis

Question 28

what type of run is PDH rxn (conversion of pyruvate to AcCoA)?

Answer 28

oxidative decarboxylation

Question 29

what are the subunits of PDH?

Answer 29

E1, E2, E3 (catalyic subunits) | & PDH Kinase & Phosphatase (regulatory subuints)

Question 30

what determines the direction of LDH rxn?

Answer 30

pyruvate/lactate ratio

Question 31

how is PDH activity regulated?

Answer 31

1) allosteric effectors on PDH catalytic subunits | 2) regulation of catalytic subunits by PDH kinase & PDH phosphatase

Question 32

what activates PDH?

Answer 32

PDH phosphatase (dephosphorylates)

Question 33

what inactivates PDH?

Answer 33

PDH kinase (phosphorylates)

Question 34

how are PDH kinase & PDH phosphatase regulated?

Answer 34

allosteric effectors & insulin

Question 35

what does deficiency in CoA and pantothenic acid cause?

Answer 35

burning foot syndrome

Question 36

what inhibits citrate synthase?

Answer 36

citrate and ATP

Question 37

what inhibits isocitrate dehydrogenase?

Answer 37

NADH

Question 38

what stimulates isocitrate dehydrogenase

Answer 38

ADP & NAD+

Question 39

what inhibits alpha-ketoglutarate dehydrogenase?

Answer 39

succinyl-CoA, NADH ATP

Question 40

what causes biotin deficiency?

Answer 40

eating raw eggs (avidin)

Question 41

what are the symptoms of biotin symptoms?

Answer 41

dermatitis, glossitis, loss of appetite

Question 42

A 10-year-old boy has suffered from slowly progressing ataxia (poor motor coordination) since the age of 5. a blood test shows abnormal elevation of lactic acid levels after an oral glucose load. deficiency of which of the following enzymes or transporters is the most likely cause of the boy's condition?

Answer 42

pyruvate dehydrogenase

Question 43

the primary function of the TCA cycle is to:

Answer 43

produce reduced nucleotides (NADH & FADH2) from metabolic fuels to permit oxidative phosphorylation

Question 44

an uncoupler of oxidative phosphorylation:

Answer 44

allows electron transport to proceed without ATP synthesis