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metabolism Flashcards

1
Q

metab that occurs in mito

A

fatty acid BETA-ox.
acetyl co-A prod.
TCA cycle.
ox phos.

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2
Q

metab that occurs in cytoplasm

A 
glycolysis.
FA synth.
HMP shunt.
protein synth (RER).
steroid synth (SER).
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3
Q

metab that occurs in both mito and cyto

A

Heme synth.
Urea cycle.
Gluconeogenesis.

HUGS take two.

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4
Q

kinase

A

use ATP to add high-energy phosphate onto substrate

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5
Q

phosphorylase

A

adds inorganic phosphate onto substrate without using ATP

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6
Q

phosphatase

A

removes phosphate group from substrate

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7
Q

dehydrogenase

A

oxidizes substrate

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8
Q

carboxylase

A

transfers CO2 groups with help of BIOTIN

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9
Q

rate-determining enzyme: glycolysis

A

phosphofructokinase-1

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10
Q

rate-determining enzyme: gluconeogenesis

A

fructose-1,6-bisphosphatase

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11
Q

rate-determining enzyme: TCA cycle

A

isocitrate dehydrogenase

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12
Q

rate-determining enzyme: glycogen synthesis

A

glycogen synthase

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13
Q

rate-determining enzyme: glycogenolysis

A

glycogen phosphorylase

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14
Q

rate-determining enzyme: HMP shunt

A

glucose-6-phosphate dehydrogenase

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15
Q

rate-determining enzyme: de novo pyrimidine synth

A

carbamoyl phosphate synthetase II

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16
Q

rate-determining enzyme: de novo purine synth

A

glutamine-PRPP amidotransferase

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17
Q

rate-determining enzyme: urea cycle

A

carbamoyl phosphate synthetase I

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18
Q

rate-determining enzyme: fatty acid synth

A

acetyl-coA carboxylase (ACC)

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19
Q

rate-determining enzyme: fatty acid oxidation

A

carnitine acyltransferase 1

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20
Q

rate-determining enzyme: ketogenesis

A

HMG-CoA synthase

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21
Q

rate-determining enzyme: chol synth

A

HMG-CoA reductase

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22
Q

aerobic metab of glucose produces?

A

32 ATP: malate-aspartate shuttle in heart, liver.

30 ATP: glycerol-3-phosphate shuttle in muscle.

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23
Q

anaerobic glycolysis produces?

A

2 net ATP per glucose molec

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24
Q

activated carrier of phosphoryl

A

ATP

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25
Q

activated carrier of electrons

A

NADH.
NADPH.
FADH2.

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26
Q

activated carrier of acyl

A

coenzyme A.

lipoamide.

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27
Q

activated carrier of CO2

A

biotin

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28
Q

activated carrier of 1 carbon units

A

tetrahydrofolate

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29
Q

activated carrier of CH3 groups

A

SAM

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30
Q

activated carrier of aldehydes

A

TPP (thiamine pyrophosphate, B1)

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31
Q

universal electron acceptor: NAD+

A

nicotinamide.
from vit B3.

used in catabolic processes to carry reducing equivalents away as NADH.

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32
Q

universal electron acceptor: NADP+

A

nicotinamide.
NADPH made in HMP SHUNT.
used in anabolic processes as a SUPPLY of reducing equivalents.

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33
Q

universal electron acceptor: FAD+

A

flavin nucleotides.

from vit B2.

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34
Q

processes that use NADPH

A
  1. anabolic processes: steroid and FA synth.
  2. respiratory burst.
  3. P450.
  4. glutathione reductase.
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35
Q

hexokinase/glucokinase

A

phosphorylate glucose to yield GLUCOSE-6-PHOSPHATE.

1st step of glycolysis AND glycogen synth in liver, depending on enz location.

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36
Q

hexokinase

A

UBIQUITOUS.
high affinity (low Km).
low capacity (low Vmax).
NOT induced by insulin.

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37
Q

what inhibits hexokinase?

A

glucose 6-phosphate via feedback inhib

38
Q

glucokinase

A

LIVER and BETA CELLS of pancreas.
low affinity (high Km).
high capacity (high Vmax).
induced by insulin.

39
Q

what does glucokinase with excess glucose?

A

phosphorylates it (after a meal) to SEQUESTER it in the liver - liver serves as blood glucose buffer

40
Q

which steps in glycolysis require ATP?

A
  1. hexo/glucokinase.

2. phosphofructokinase-1.

41
Q

what inhibits glucokinase?

A

fructose-6-phosphate

42
Q

what inhibits PFK1?

A

ATP.

citrate.

43
Q

what stimulates PFK1?

A

AMP.

fructose 2,6-bisphosphate.

44
Q

which steps in glycolysis produce ATP?

A
  1. phosphoglycerate kinase.

2. pyruvate kinase.

45
Q

what inhibits PK?

A

ATP.

alanine.

46
Q

what stimulates PK?

A

fructose 1,6-bisphosphate

47
Q

fructose bisphosphatase 2

A

active in FASTING state:
increase glucagon = cAMP = protein kinase A = increase fructose bisphosphatase 2.

F26BP to F6P for gluconeogenesis.
decrease PFK2 = less glycolysis.

48
Q

phosphofructokinase-2

A

active in FED state:
increase insulin = decrease cAMP = decrease protein kinase A = increase PFK2.

F26BP stimulates PFK1 for more glycolysis.
decrease fructose bisphosphatase 2.

49
Q

pyruvate dehydrogenase complex RXN

A

pyruvate + NAD+ + CoA =

acetyl coA + CO2 + NADH

50
Q

pyruvate dehydrogenase complex COFACTORS

A
  1. TPP (B1)
  2. FAD (B2)
  3. NAD (B3)
  4. CoA (B5)
  5. lipoic acid
51
Q

what activates pyruvate dehydrogenase complex?

A

exercise:
increased NAD+/NADH ratio.
increased ADP.
increased Calcium.

52
Q

what other complex is similar to pyruvate dehydrogenase complex?

A

alpha-ketoglutarate dehydrogenase complex in TCA cycle. same cofactors, similar substrate.

alpha-KG –> succinyl CoA.

53
Q

what inhibits lipoic acid?

A

arsenic - cause vomiting, pain, rice water stools, garlic breath, delirium.

54
Q

TX of arsenic poisoning

A

dimercaprol (chelator) to displace arsenic ions

55
Q

pyruvate dehydrogenase deficiency

A

back up of substrate (pyruvate, alanine).

increased LDH activity to regenerate NAD+ causes LACTIC ACIDOSIS.

can be congenital or
acquired (alcoholics, B1 def).

56
Q

findings in pyruvate dehydrogenase deficiency

A

neuro defects

57
Q

TX of pyruvate dehydrogenase deficiency

A

increased intake of KETOGENIC nutrients-
high fat content or
increased Lysine and Leucine (the only purely ketogenic AAs)

58
Q

pyruvate can be metabolized into:

A
  1. alanine.
  2. oxaloacetate.
  3. acetyl CoA.
  4. lactate.
59
Q

function of alanine from pyruvate

A

carries amino groups from muscle TO LIVER

60
Q

function of oxaloacetate from pyruvate

A

replenish TCA cycle or

used in gluconeogenesis

61
Q

function of acetyl CoA from pyruvate

A

transition from glycolysis to TCA

62
Q

function of lactate from pyruvate

A

end of anaerobic glycolysis

63
Q

which organs use anaerobic glycolysis (and thus produce lactate)?

A 
RBCs.
leukocytes.
kidney medula.
testes.
lenses.
cornea.
64
Q

what inhibits pyruvate dehydrogenase?

A

ATP.
acetyl CoA.
NADH.

65
Q

irreversible enzymes in TCA

A
  1. pyruvate dehydrogenase.
  2. citrate synthase.
  3. isocitrate dehydrogenase.
  4. alpha-ketoglutarate dehydrogenase.
66
Q

intermediates in TCA (in order)

A 
Citrate.
Isocitrate.
alpha-Ketoglutarate.
Succinyl CoA.
Succinate.
Fumarate.
Malate.
Oxaloacetate.

“Citrate Is Kreb’s Starting Substrate For Making Oxaloacetate”

67
Q

NADH electrons enter mito…

A

via malate-aspartate

or glycerol-3-phosphate shuttle.

68
Q

where does FADH2 enter ETC/oxphos?

A

complex II (at lower energy level than NADH)

69
Q

ATP produced by ATP synthase

A

using proton gradient formed in intermembranous space.

1 NADH = 3 ATP.
1 FADH2 = 2 ATP.

70
Q

ox phos poison: electron transport inhibitors

A

directly inhibit ETC, causing decreased proton gradient and block of ATP synth.

  1. rotenone.
  2. CN-
  3. antimycin A.
  4. CO
71
Q

ox phos poison: ATP synthase inhibitors

A

directly inhibit mito ATP synthase, causing increased proton gradient.

NO ATP IS PRODUCED bc electron transport stops.

drug: oligomycin

72
Q

ox phos poison: uncoupling agents

A

increase permeability of membrane, causing decreased proton gradient and increased O2 consumption.

ATP synth stops but ETC continues.
produces heat.

  1. 2,4-dinitrophenol.
  2. aspirin (overdose).
  3. thermogenin (brown fat).
73
Q

gluconeogenesis occurs in?

A

LIVER.

enzymes also found in kidney, intestinal epith.

74
Q

gluconeogenesis irreversible enzymes

A

Pyruvate carboxylase.
PEP carboxykinase.
Fructose-1,6-bisphosphatase.
Glucose-6-phosphatase.

“Pathway Produces Fresh Glucose”

75
Q

deficiency of gluconeogenesis enzymes leads to?

A

hypoglycemia

76
Q

why cant MUSCLE participate in gluconeogenesis?

A

it lacks glucose-6-phosphatase

77
Q

what type of FA can also contribute to gluconeogenesis?

A

odd-chain FA: yield 1 propionyl CoA during metabolism, which can enter TCA as succinyl CoA and undergo gluconeogenesis.

*even-chain FAs only yield acetyl CoA equivalents

78
Q

pyruvate carboxylase

A

in mito.
pyruvate to oxaloacetate.
requires biotin, ATP.
activated by acetyl CoA.

79
Q

PEP carboxykinase

A

in cytosol.
oxaloacetate to PEP.
requires GTP.

80
Q

fructose-1,6-bisphosphatase

A

in cytosol.

fructose-1,6-bisphosphate to fructose-6-phosphate.

81
Q

glucose-6-phosphatase

A

in ER.

glucose-6-phosphate to glucose.

82
Q

HMP shunt

A

key role: provide NADPH from abundant G6P supply.

aka pentose phosphate pathway.

83
Q

phases of HMP shunt

A
  1. oxidative (irreversible).

2. nonoxidative (reversible).

84
Q

products of HMP shunt

A
  1. NADPH.
  2. ribose.
  3. glycolytic intermediates (G3P, F6P).
85
Q

sites of HMP shunt

A

CYTOPLASM-
lactating mammary glands.
liver, adrenal cortex (FA/steroid synth).
RBCs (glutathione reduction).

86
Q

ATP in HMP shunt

A

none used or produced

87
Q

oxidative rxn of HMP shunt

A

glucose 6-phosphate
yields 2 NADPH, CO2, ribulose-5P
(multiple in-between steps)
via G6P dehydrogenase.

*RATE-LIMITING STEP

88
Q

nonoxidative rxn of HMP shunt

A

ribulose-5P (from oxidative phase)
yields ribose-5P, G3P, F6P
(multiple in-between steps)
via transketolase with B1 cofactor.

89
Q

what enz is activated in respiratory (oxidative) burst?

A

NADPH oxidase -
membrane bound.
in neutrophils, monocytes.

*NADPH involved in ROI production and neutralization

90
Q

role of resp burst

A

immune response: rapid release of reactive oxygen intermediates (ROIs)

91
Q

sequence of enzymes in ROI prod

A

NADPH oxidase.
superoxide dismutase.
myeloperoxidase OR catalase/glutathione peroxidase

Biochem (7 decks)

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