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STEP 1 > 11b: Biochem metabolism > Flashcards

11b: Biochem metabolism Flashcards

1
Q

List the metabolic pathways that occur only in mitochondria

A

“FAT OK”

  1. FA (beta) ox
  2. Acetyl-CoA production
  3. TCA cycle
  4. Ox phos
  5. Ketogenesis
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2
Q

List the metabolic pathways that occur in both cytoplasm and mito

A

“HUGs take two”

  1. Heme synthesis
  2. Urea cycle
  3. Gluconeogenesis
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3
Q

Difference between phosphorylase and kinase

A

Kinase catalyzes PO4 group transfer from HIGH E molecule (ex: ATP)
Phosphorylase transfers inorganic PO4 without using ATP

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4
Q

Dehydrogenase enzymes catalyze (X) reactions

A

X = Redox

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5
Q

Rate-determining enzyme of gluconeogenesis

A

Fruc-1,6-bisphosphatase

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6
Q

Rate-determining enzyme of TCA cycle

A

Isocitrate dehydrogenase

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7
Q

Rate-determining enzyme of de novo purine synthesis

A

Gln-PRPP amidotransferase

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8
Q

Rate-determining enzyme of FA synthesis

A

Acetyl-CoA carboxylase

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9
Q

Rate-determining enzyme of FA ox

A

Carnitine acyltransferase I

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10
Q

Rate-determining enzyme of Ketogenesis

A

HMG-CoA synthase

Note: in cholesterol synthesis, it’s HMG-CoA reductase

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11
Q

List the positive regulators of PFK-1

A

AMP and Fructose-2,6-bisphosphate

neg regulators are citrate, ATP

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12
Q

List the positive regulators of Fructose-1,6-bisphosphatase

A

Citrate

neg regulators: AMP and Fructose-2,6-bisphosphate = the pos regulators for PFK-1

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13
Q

Glycogen synthase positive regulators:

A

Gluc-6P, insulin, cortisol

the negative regulators of glycogen phosphorylase except cortisol

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14
Q

Glycogen synthase negative regulators:

A

Epi, glucagon

the positive regulators of glycogen phosphorylase

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15
Q

Carbamoyl phosphate synthetase I regulator:

A

N-acetylglutamate (pos regulator)

Note: urea cycle enzyme

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16
Q

Acetyl-CoA carboxylase neg regulators

A

Glucagon and palmitoyl-CoA

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17
Q

Carnitine acyltransferase I neg regulator

A

Malonyl-CoA

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18
Q

T/F: Thyroxine is positive regulator of HMG-CoA reductase

A

True

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19
Q

(X) chemical element causes glycolysis to produce zero net ATP

A

X = arsenic

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20
Q

RBCs can run glycolysis without generating any ATP. What’s the function of this?

A

Create 2,3-BPG from 1,3-BPG via BPG mutase;

2,3-BPG can then be converted into 3-phosphoglycerate and return to glycolysis, but no ATP made

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21
Q

CoA and lipoamide are important carrier molecules for:

A

Acyl groups

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22
Q

Biotin is important carrier molecule for:

A

CO2

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23
Q

THF is important carrier molecule for:

A

1-C units

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24
Q

S-adenosylmethionine (SAM) is important carrier molecule for:

A

CH3 (methyl) groups

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25
Q

(Hexokinase/glucokinase) found in most tissues except (X)

A

Hexokinase;

X = beta cells of pancreas, liver

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26
Q

(Hexokinase/glucokinase) has higher affinity for glucose and (higher/lower) capacity/Vmax

A

Hexokinase (lower Km); lower Vmax

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27
Q

(Hexokinase/glucokinase) induced by insulin and (Hexokinase/glucokinase) neg regulation by Gluc-6P

A

Glucokinase

Hexokinase

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28
Q

Co-factors for Pyruvate Dehydrogenase

A

“Tender Loving Care For Nancy”

  1. TPP (Thiamine pyrophosphate)
  2. Lipoic acid (inhibited by arsenic)0
  3. CoA
  4. FAD
  5. NAD
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29
Q

Rx for Pyruvate DH deficiency

A

Increase intake of ketogenic nutrients (high fat content or high Lys/Leu); generation of Acetyl-CoA instead of Pyruvate

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30
Q

Alanine can be converted to Pyruvate via (X) enzyme which requires (Y) cofactor. In the process, alanine’s (Z) group is given to:

A

X = ALT (alanine aminotransferase)
Y = B6
Z = amino
alpha-KG (to form Glu)

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31
Q

Which TCA cycle enzymes are irreversible?

A

Citrate synthase
Isocitrate DH
alphaKG DH

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32
Q

ETC: Complex IV is inhibited by…

A

CN, CO

“CN and CO inhibit complex four”

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33
Q

ETC: Complex I is inhibited by…

A

Rotenone

“rotenONE inhibits complex ONE”

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34
Q

ETC: Complex (X) is the ATP synthase

A

X = V

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35
Q

List some examples of ETC uncouplers

A
  1. Dinitrophenol (illicitly used for weight loss)
  2. Aspirin OD (hence fevers)
  3. Thermogenin (in brown fat)

Remember, uncouplers cause high O2 consuption and heat generation

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36
Q

Irreversible enzymes of gluconeogenesis. Where is the location of each?

A
  1. Pyruvate carboxylase (mito)
  2. PEP carboxykinase (cytosol)
  3. Fructose-1,6-bisphosphatase (cytosol)
  4. Glucose-6 phosphatase (ER)
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37
Q

T/F: Muscle, kidney, and liver can participate in gluconeogenesis.

A

False - not muscle (lacks gluc-6 phosphatase)

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38
Q

(Odd/even)-chain FAs can participate in gluconeogenesis

A

Odd (can generate propionyl-CoA which enters TCA as succinyl-CoA)

Note: Even-chain FAs only generate Acetyl-CoA so can’t participate

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39
Q

Aldolase B, deficient in (X) disorder, is responsible for which conversion/reaction?

A

X = fructose intolerance

Fructose 1P to DHAP and glyceraldehyde

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40
Q

Which essential AAs are solely glucogenic?

A

Met, His, Val

“I Met His Valentine, she is so sweet (glucogenic)”

41
Q

(X) AAs are especially required during periods of growth. (Y) AAs are high in histones.

A 
X = Arg, His
Y = Arg, Lys (basic so bind neg charged DNA)
42
Q

The Cori cycle is an exchange of Glucose and (X) by which two organs?

A

X = Lactate

Muscle (gives lactate to liver) and Liver (gluconeogenesis to give glucose back to muscle)

43
Q

The Cahill cycle is an exchange of Glucose and (X) by which two organs?

A

X = Alanine
Muscle (makes Ala from pyruvate and gives it to liver) and Liver (makes pyruvate and then glucose via gluconeogenesis to give back to muscle)

44
Q

Most common urea cycle disorder:

A 
Ornithine Transcarbamylase (OTC) deficiency; 
orotic acid high in blood/urine WITH hyperammonemia
45
Q

Why is orotic acid (low/high) in Ornithine Transcarbamylase (OTC) deficiency?

A

Buildup of carbamoyl phosphate get shunted to pyrimidine synthesis pathway and converted to orotic acid

46
Q

Phe to Tyr requires (X) cofactor. Tyr to Dopa requires (Y) cofactor. Dopa to DA requires (Z) cofactor.

A 
X = Y = BH4 (tetrahydrobiopterin)
Z = B6
47
Q

Melanin made from (X), which is made from (Y)

A 
X = Dopa (via tyrosinase)
Y = Tyr (via tyrosine hydroxylase)
48
Q

DA to NE synthesis requies (X) cofactor. NE to Epi requires (Y) cofactor

A 
X = Vit C
Y = SAM (methyl donation; hence, name of enzyme is PNMT, Phenylethanolamine-N-methyltransferase)
49
Q

Patient with Sx of PKU also have elevated prolactin levels. What’s going on?

A

BH4 deficiency (can’t convert Phe into Tyr or Tyr into DOPA, so low DA levels means high prolactin)

50
Q

Melatonin made from which AA?

A

Trp (via SA synthesis then melatonin from SA)

51
Q

(B6/BH4) required for SA synthesis from Trp

A

Both

52
Q

Heme synthesis starts off with which two substrates?

A

Gly and Succinyl CoA

53
Q

Glutathione made from which AA?

A

Glu

54
Q

Patient with (X) metabolic disorder can’t have (Y) artificial sweetener because it contains:

A

X = PKU
Y = aspartame
Phe

55
Q

Maple syrup urine disease Rx:

A

Restrict Ile, Leu, Val; supplement Thiamine

56
Q

Patient with blue-black ear cartilage/sclerae and black urine upon exposure to air. Which enzyme deficiency?

A

Alkaptonuria; deficient homogentisate oxidase (involved in Tyr degradation to fumarate)

57
Q

List the three different types of homocystinuria

A
  1. Cystathione synthase deficiency
  2. Methionine synthase deficiency
  3. Low affinity of cystathionine synthase for PRP (cofactor involving B6)
58
Q

Cystathione synthase deficiency causes (X) disorder and should be treated with:

A

X = homocystinuria

Low methionine (since homocysteine is being shunted down that pathway); high Cys, B6, B12, and folate supplementation

59
Q

Glycogenolysis in muscle stimulated by (phosphorylase/phosphatase) activation by (X).

A

Glycogen phosphorylase
X = Ca (directly) and Epi (via cAMP)

*Ca more powerful activator

60
Q

Glycogenolysis in liver stimulated by (phosphorylase/phosphatase) activation by (X)

A

Glycogen Phosphorylase

X = Epi and glucagon (via cAMP)

61
Q

30 yo M with bilateral ptosis, facial muscle atrophy, and stiff/delayed muscle relaxation after handshake. Father has similar, but less severe, Sx.

A

Myotonic dystrophy (CTG tri-NT expansion)

62
Q

Stage (X) of sleep is referred to as “restorative” sleep, important for rejuvenation of the brain. If reduced, patient will complain of (Y)

A 
X = 3 (deep/delta/slow-wave) NREM
Y = not feeling rested

Declines significantly (almost vanishes) in elderly

63
Q

T/F: REM sleep declines significantly as one ages.

A

False - tends to stay relatively constant (at 20%) until about 80 yo, then declines

64
Q

High anti-RNP (aka anti-U1 ribonucleoprotein) Ab is specific for:

A

Mixed connective tissue disease

65
Q

Glycogen synthesis: glucose 1P becomes (X) with action of (Y) enzyme

A 
X = UDP-glucose
Y = UDP glucose pyrophosphorylase
66
Q

Glycogenolysis: list the two debranching enzymes and the function of each

A
  1. 4aD-glucanotransferase: removes 3/4 glucose residues from branch on limit dextrin until there’s only 1 glucose left on it
  2. alpha-1,6-glucosidase: removes last glucose residue on branch
67
Q

Von Gierke’s disease: which enzyme deficient? Which metabolic pathway(s) impaired?

A

Glucose-6-phosphatase

Gluconeogenesis and glycogenolysis

68
Q

Rx for Von Gierke disease

A

Frequent oral glucose/cornstarch; avoid fructose and galactose

69
Q

Pompe disease: which enzyme deficient? Which metabolic pathway(s) impaired?

A

Acid alpha-1,4-glucosidase aka acid maltase (a lysosomal enzyme)

Glycogenolysis

70
Q

Cori disease is a (mild/severe) form of (X) with which enzyme deficiency? Which metabolic pathway(s) impaired?

A

Mild
X = von gierke disease

Debranching enzyme (alpha-1,6-glucosidase)
Glycogenolysis (but gluconeogenesis is intact)
71
Q

Which glycogen storage disease will likely cause patient to be in metabolic acidosis?

A

Von Gierke (high lactic acid)

72
Q

Triad: neuropathic pain, decreased sweating (hypohidrosis), and dark red, non-blanching papules over groin/butt/umbilicus. Which disease?

A

Fabry disease (alpha-galatosidase A deficiency)

Skin findings = angiokeratomas

73
Q

Long-term consequence of Fabry disease

A

Progressive renal failure and CV disease

74
Q

Which substrate is accumulating in Fabry disease?

A

Ceramide trihexoside (a sphingolipid)

75
Q

Metachromatic leukodystrophy is deficiency in (X)

A

Lysosomal storage disease
X = Arylsulfatase A
(accumulation of cerebroside sulfate)

76
Q

Krabbe disease: which enzyme deficient?

A

Galactocerebrosidase (accumulation of galactocerebroside)

77
Q

Lysosomal storage disease with Sx of ataxia and dementia due to central/peripheral demyelination

A

Metachromatic leukodystrophy

78
Q

Lysosomal storage disease with Sx of optic atrophy, developmental delay, peripheral neuropathy. Destruction of oligodendrocytes.

A

Krabbe

79
Q

“Crumpled tissue paper” cells seen in (X) storage disease are actually what kind of cells?

A

X = Gaucher (lysosomal storage disease)

Lipid-laden macrophages

80
Q

Gaucher disease: which enzyme deficient?

A

Glucocerebrosidase (beta-glucosidase); accumulated substrate is Glucocerebroside

81
Q

Which lysosomal storage disease has Sx of osteoporosis, avascular necrosis and bone crises?

A

Gaucher disease

82
Q

FA synthesis requires (X) shuttle and FA degradation requires (Y) shuttle.

A 
X = citrate (citrate leaves mito and enters cytoplasm)
Y = carnitine (Acyl-CoA enters mito for beta-ox)
83
Q

FA undergo beta-oxidation and (X) key enzyme converts them to (Y)

A 
X = Acyl-CoA Dehydrogenase
Y = Acetyl-CoA
84
Q

Triglyceride stored in adipose is broken down into glycerol and FFA by which enzyme?

A

Hormone-sensitive lipase

85
Q

In well-fed state, FA (ox/synth) is inhibited via (X) inhibition of (Y) shuttle.

A

Oxidation
X = malonyl-coa
Y = carnitine

86
Q

Which tissues can’t use ketone bodies?

A
  1. Erythrocytes (no mitochondria)

2. Liver (lacks enzyme)

87
Q

Urine test for ketones detects:

A

Acetoacetate (can’t detect beta-hydroxybutyrate)

88
Q

Metabolic fuel use: stored ATP depleted in (X) amount of time and Creatine phosphate in (Y) amount of time

A 
X = 2 s
Y = 10 s
89
Q

Glycogen reserves depleted after (X) day(s) starvation. (Fat/protein) is consumed at more rapid rate throughout the subsequent days/weeks of starvation.

A

X = 1

Fat

90
Q

After (X) days of starvation, adipose stores/ketone bodies become main source of E

A

X = 3

91
Q

Lipoprotein lipase is found on/in which cells?

A

On vascular endothelial surface

degrades TGs circulating in chylomicrons/VLDLs

92
Q

Which enzyme is responsible for nascent HDL conversion to mature HDL?

A

LCAT (esterifies plasma cholesterol so that HDL can then transfer cholesterol esters to other lipoproteins)

93
Q

Which enzyme is responsible for cholesterol ester transfer from HDL to other lipoproteins??

A

CETP (Cholesterol Ester Transfer Protein)

94
Q

Alcohol increases synthesis of which lipoprotein?

A

HDL

95
Q

Abetalipoproteinemia: loss of function of (X). It’s important to supplement with (Y) for treatment

A

X = MTP (microsomal TG transfer protein; necessary for proper apoB folding/lipid transfer to chylomicrons/VLDL)

Y = large doses of vit E (deficiency of this vit causes spinocerebellar degeneration)

96
Q

Familial dysplipidemia: Sx of pancreatitis, hepatosplenomegaly, and creamy layer (milky plasma) in supernatant.

A

Hyper-chylomicronemia (AR; LPL or apolipoprotein C-II deficient)

97
Q

T/F: All familial dysplipidemias increase risk for atherosclerosis.

A

False - Hyperchylomicronemia and hyper-TG don’t increase atherosclerosis risk

98
Q

Which familial dysplipidemias increase risk for early MI?

A
  1. Familial hypercholesterolemia (absent/defective LDL R)

2. Dysbeta-lipoproteinemia (defective ApoE)

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