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Biochemistry - step > FA 2015 - Metabolism > Flashcards

FA 2015 - Metabolism Flashcards

1
Q

Rate Limiting of Glycolysis

A

phosphofructokinase - 1

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2
Q

regulators of rate limiting of glycolysis

A

phosphofructokinase-1
+ AMP + fructose26bp
- ATP - citrate

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3
Q

Rate limiting of gluconeogenesis

A

fructose 1,6 bisphosphatase

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4
Q

regulators of rate limiting of gluconeogenesis

A

fructose 1,6 bisphosphatase
+ ATP + acetyl-CoA + citrate
- AMP - fructose 26bp

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5
Q

rate limiting of the TCA

A

isocitrate dehydrogenase

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6
Q

regulators of rate limiting of TCA

A

isocitrate dehydrogenase
+ ADP
- ATP - NADH

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7
Q

rate limiting of glycogenesis

A

glycogen synthase

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8
Q

regulators of rate limiting of glycogenesis

A

glycogen synthase
+ insulin + cortisol + glucose 6p
- epi - glucagon

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9
Q

rate limiting of glycogenolysis

A

glycogen phosphorylase PLP

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10
Q

regulators of rate limiting of glycogenolysis

A

glycogen phosphorylase PLP
+ epi + glucagon + AMP (also stimulates glycolysis)
- insulin - cortisol - glucose 6P

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11
Q

rate limiting of HMP shunt

A

glucose 6 phosphate dehydrogenase

XLR

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12
Q

regulators of rate limiting of HMP shunt

A

glucose 6 phosphate dehydrogenase XLR
+ NADP
- NADPH

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13
Q

rate limiting of de novo pyrimidine synthesis

A

carbamoyl phosphate synthetase II

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14
Q

regulators of rate limiting of de novo pyrimidine synthesis

A

carbamoyl phosphate synthetase II
+ ATP
- UDP

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15
Q

rate limiting of de novo purine synthesis

A

glutamine-phosphoribosylpyrophosphate (PRPP) amidotransferase

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16
Q

regulators of rate limiting of de novo purine synthesis

A

glutamine-phosphoribosylpyrophosphate (PRPP) amidotransferase
- AMP - GMP - IMP

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17
Q

rate limiting of urea cycle

A

carbamoyl phosphate synthetase I

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18
Q

regulators of rate limiting of urea cycle - cytosol and mito

A

carbamoyl phosphate synthetase I

+ N-acetylglutamine

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19
Q

rate limiting of fatty acid synthesis - cytosol

A

acetyl-coA carboxylase (biotin as cofactor)

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20
Q

regulators of rate limiting of fatty acid synthesis - cytosol

A

acetyl-CoA carboxylase (biotin as cofactor)
+ insulin + citrate (citrate inhibits glycolysis)
- glucagon - palmitoyl CoA

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21
Q

rate limiting of fatty acid oxidation - mito

A

carnitine acyltransferase I

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22
Q

regulators of rate limiting of fatty acid oxidation - mito

A

carnitine acyltransferase I

- malonyl CoA

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23
Q

rate limiting of ketogenesis - mito

A

HMG CoA synthase

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24
Q

regulators of rate limiting of ketogenesis - mito

A

HMG CoA synthase

NONE waddup.

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25
Q

rate limiting of cholesterol synthesis - cytosol

A

HMG CoA reducatase

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26
Q

regulators of rate limiting of cholesterol synthesis - cytosol

A

HMG CoA reductase
+ insulin + thyroxine
- glucagon - cholesterol

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27
Q

where does insulin play a regulatory role?

A

stimulates glycogenesis AND inhibits glycogenolysis

stimulates cholesterol synthesis

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28
Q

where does glucagon play a regulatory role?

A

inhibits glycogenesis AND stimulates glycogenolysis

inhibits cholesterol synthesis

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29
Q

where does AMP play a regulatory role?

A

stimulates glycolysis AND inhibits gluconeogenesis
inhibits de novo purine synthesis
stimulates glycogenolysis (wants to get sugar up in er to make ATP)

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30
Q

where does ATP play a regulatory role?

A

inhibits glycolysis AND stimulates gluconeogenesis
inhibits TCA
stimulates de novo pyrimidine synthesis

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31
Q

in general, what is NAD+ used asÉ

A

in catabolic processes to carry away reducing agents as NADH

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32
Q

in general, what is NADPH used forÉ

A

in anabolic processes (fatty acid synthesis and steroid synthesis) as a source of a reducing agent

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33
Q

specifically what is NADPH used for times six thingsÉ

A

1) anabolic processes
2) fatty acid synthesis
3) steroid synthesis
4) glutathione reductase
5) respiratory burst
6) cytochrome P450 – OH in microsome with CYP2E1

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34
Q

compare and contrast hexokinase and glucokinase please

A

hexokinase - have at tissues that need to get glucose at all times; so has a high affinity/low Km and a low capacity/low Vm; insulin doesn’t want to store in these tissues so does not induce its expression; it is inhibited by its downstream product glucose 6 phosphate and is not affected in MODY

glucokinase - on tissues that want to store glucose/use it for regulation ie liver and beta pancreatic cells; therefore has a low affinity/high Km to sense only when glucose is high and has a high capacity/Vm so can keep er coming in when glucose is plentiful; insulin affects storage of glucose thus induces glucokinase expression; it is not inhibited by g6p and is affected in MODY

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35
Q

regulation of hexokinase

A

inhibited by g6P

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36
Q

regulation of glucokinase

A

inhibited by f1P

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37
Q

regulation of pyruvate kinase

A

stimulated by f16bp

inhibited by ATP and alanine

38
Q

Describe role of fructose 2,6 bisphosphate in the FED state

A

FED STATE - increased glucagon - increased AC - increased cAMP - increased PKA activity - decreased PFK2 activity - decreased fructose 26 bp - no stimulation of PFK1 AND increased fructose 26bp activity so less fructose 26bp around inhibiting fructose 16 bp – fructose 6p is converted into glucose 6p for gluconeogenesis

39
Q

Describe role of fructose 2,6 bisphosphate in the FAST state

A

FAST STATE - increased insulin - decreased AC - decrease cAMP - decreased PKA activity - increased PFK2 activity - increased fructose26bp - increased PFK activity – glycolysis AND decreased fructose 26bp activity – more fructose 26bp to inhibit fructose 16bp – no gluconeogenesis

whhoahh.

40
Q

cofactors required by the pyruvate dehydrogenase complex of enzymes located in the blank for bonus points

A

mitochondria

1) pyrophosphate; B1; thiamine; TPP
2) FAD; B2; riboflavin
3) NAD; B3; niacin
4) CoA; B5; pantothenic acid
5) lipoic acid

41
Q

what inhibits lipoic acid

A

arsenic

42
Q

vomiting
garlic breath
0 ATP from glycolysis/TCA
rice water stools

A

arsenic poisoning

inhibits lipoic acid (PDH)

43
Q

what are the regulators of PDH

A 
increases at exercise where ATP is in demand:
* increased NAD+/NADH ratio
* ADP
* Ca++
inhibited by
*NADH
*ATP
*Acetyl CoA
44
Q

what are the only two purely ketogenic amino acids and who cares?

A

lysine and luecine

can give to PDH complex deficiency patients.

45
Q

what tissues/cells utilize anaerobic glycolysis as major source of energy?

A
  1. rbc
  2. wbc
  3. testes
  4. kidney medulla
  5. lens
  6. cornea
46
Q

regulators of isocitrate dehydrogenase

A

+ ADP

- ATP - N ADH

47
Q

regulators of alpha-ketoglutarate dehydrogenase

A
  • ATP - NADH - succinyl CoA
48
Q

List the oxidative phosphorylation poisons that directly inhibit the electron transport chain and which complexes they act on.

A

rotenone- complex I
actinomycin A - complex III
Co and cyanide - complex IV
decrease proton gradient

49
Q

List the oxidative phosphorylation poisons that directly inhibit ATP synthase

A

oligomycin

increases proton gradient

50
Q

List the oxidative phosphorylation poisons that are uncoupling agents

A

2,4 dinitrophenol
aspirin at o/d – get fever with o/d
thermogenin at brown fat
make inner mitochondrial membrane more permeable so proton gradient is lost; electron transport continues, O2 consumption increases, heat is produced.

*remember Dr Williams and Roho BCHM first termzees in drill**

51
Q

list the irreversible enzymes in gluconeogenesis. include locations and cofactors if applicable

A

pyruvate carboxylase - ATP, B5 @ mito
PEP carboxykinase - GTP @ cytosol
fructose 1,6 bisphosphatase - @ cytosol
glucose 6 phosphatase - @ ER

52
Q

list the regulators of the irreversible enzymes in gluconeogenesis

A

pyruvate carbosylase: + acetyl CoA
PEP carboxykinase: none
fructose 1,6 bisphosphatase: +ATP, citrate, NADH -AMP and fructose 1,6 bisphosphate
glucose 6 phosphatase: none

53
Q

why can’t muscle participhate in gluconeogenesis?

A

does not have glucose 6 phosphatase

54
Q

where does the HMP/pentose phosphate pathway occur in the body?

A

cytosol of a) lactating mammary glands b) liver c) adrenal cortex and d) RBCs
bc this is where glutathione reductase works, or where FA or steroids are produced.

55
Q

clumbs of oxidized/damage Hb in cytoplasm and removal by phagocytosis in the spleen

A

glucose 6 phosphate dehydrogenase deficiency
Heinz bodies and bite cells
due to lack of glutathione in reduced form bc no NADPH formed to protect and reduced H2O2 to H2O

56
Q

which cells have only aldose reductase not sorbital dehydrogenase and are therefore prone to osmotic damage when sorbitol builds up?

A

schwann cells
kidney
retina

57
Q

which cells have primarily aldose reductase and some sorbital dehydrogenase and are therefore somewhat prone to osmotic damage by sorbitol buildup?

A 
the lens
(schwann cells, retina, kidney have only aldose reductase.  boo)
so will see retinopathy, glomerulopathy (my brain cant remember if that's a thing right now... nope that's nephropathy my bad) and neuropathy first before cataracts haha finally makes sense why myelinated neurons are affected first in diabetes - not pain and temp but touch, vibration and proprioception.  rant over.  oh no its only day three.
58
Q

difference between primary and secondary and congenital lactase deficiency please

A

primary - decreased enzyme with age; prominent in Asians, Africans, native americans
secondary - due to gastroenteritis (rrrooottaa), autoimmune diseases, etc
congenital - rare, due to defective gene - will have normal intestintal biopsy.

59
Q 
bloating
cramps
flatulence
osmotic diarrhoea
decreased stool pH
increased hydrogen in breath
A

lactase deficiency

60
Q 
tremor/asterixis
slurring of speech
somnolence
vomiting
cerebral oedema
blurring of vision
MESSY HEAD
A

hyperammonemia

61
Q

how to treat hyperammonemia

A

limit protein in diet
lactulose - acidifes git and traps NH4+
rifaximin - decreases colonic ammonogenic bacteria
benzoate or phenylbutyrate - bind aa leading to excretion instead of absorption

62
Q

MOA lactulose

A

acidifies git and traps NH4+

treatment of hyperammonemia

63
Q

MOA rifixamin

A

decreases colonic ammonogenic bacteria

treatment of hyperammonemia

64
Q

MOA benzoate and phenylbutyrate

A

bind to aa leading to excretion instead of absorption

treatment of hyperammonemia

65
Q 
how do you treat this disease:
intellectural disability
osteoporosis
marfanoid habitus
kyphosis
lens subluxation (down and in)
thrombosis
atherosclerosis (stroke and MI risk)
A

homocysteniuria

a) cystathione synthase def – cysteine, B12 and folate
b) decreased affinity of cystathionine synthase for B6 – increase B6 and cysteine in diet
c) methionine synthase/homocystein methyltransferase def – increased methionine in diet

66
Q

how do you treat cystinuria?

A

good hydration and make cystine stones more soluble

a) urinary alkalinisation with acetazolamide or potassium citrate
b) chelating agents - penicillamine

67
Q

diagnostic test for cystinuria

A

urinary cyanide-nitroprusside test

UWORLD Q I GOT WRONG> no more.

68
Q 
severe fasting hypoglycemia
increased glycogen in liver
increased blood lactate
increase uric acid
increased TAGs
hepatomegaly
A

Von Gierkes disease
type I glycogen storage disease
AR
glucose-6-phosphatase

69
Q 
cardiomegaly
hypertrophic cardiomyopathy
exercise intoleranc
systemic findings
trashed heart, liver, muscle
A 
Pompe disease
type II glycogen storage disease
AR
acid maltase
lysosomal alpha 1,4 glucosidase
70
Q

gluconeogenesis intact
lactate levels normal
milder of: hyperglycemia, uric acid, TAGS, hepatomegaly

A

Cori disease
type III glycogen storage disease
AR
alpha 1,6 glucosidase

71
Q 
increased glycogen in muscle
painful muscle cramps
myoglobinuria with strenuous exercise
arrhythmias from electrolyte disturbances
normal glucose levels
A

mcArdle
type V glycogen storage disease
AR
skeletal muscle glycogen phosphorylase/myophosphorylase

72
Q

Fabry - enzyme, build up, inheritance

A

alpha-galactosidase A - ceramide trihexoside - XLR

73
Q

Gaucher - enzyme, build up, inheritance

A

glucocerebrosidase - glucocerebroside - AR

74
Q

Niemann Pick - enzyme, build up, inheritance

A

sphingomyelinase - sphingomyelin- AR

75
Q

Tay Sach - enzyme, build up, inheritance

A

hexoaminosidase A - Gm2 ganglioside - AR

76
Q

Krabbe disease - enzyme, build up, inheritance

A

galactocerebrosidase - galactocerebroside, psychosine - AR

77
Q

Metachromatic luekodystrophy - enzyme, build up, inheritance

A

arylsulfatase - cerebroside sulfatase - AR

78
Q

hurler - enzyme, build up, inheritance

A

alpha-L-iduronidase - heparan sulfate, dermatan sulfate AR

79
Q

hunter - enzyme, build up, inheritance

A

iduronate sulfatase - heparan sulfate, dermatan sulfate XLR

80
Q

peripheral neuropathy of hands and feet
cardiovascular disease
renal disease
angiokeratomas

A

fabrys - XLR - alpha-galactosidase-A, ceramide trihexoside

81
Q

which lysosomal storage disease is the most common?

A

gaucher

82
Q

hepatomegaly
pancytopenia
osteoporosis
bone crises

A

gaucher - AR - galactocerbrosidase - galactocerbroside

BONE and LIVER
no CNS/no cherry macula
gift wrap cells

83
Q

progressive neurodegeneration
hepatosplenomegaly
cherry red spot on macula

A

niemann pick - AR - spingomyelinase - sphingomyelin

CNS and LIVER
cherry macula
lipid laden foam cells

84
Q

progressive neurodegeneration
developmental delay
cherry red spot
NO hepatosplenomegaly

A

tay sach - AR - hexoaminosidase A - Gm3 ganglioside

no liver
CNS
onion skin cells

85
Q

peripheral neuropahy
developmental delay
optic neuropathy

A

krabb disease - AR - alpha-galactocerbrosidase - galactocerebroside, psychosie

globoid cells

86
Q

central and peripheral demyelination
ataxia
dementia

A

metachromatic leukodystrophy - AR - arylsulfatase - cerebroside sulfate

87
Q 
developmental delay
gargoylism
airway obstruction
hepatosplenomegaly
corneal clouding
A

hurler - alpha-L-iduronidase - AR

88
Q 
MILDER
developmental delay
gargoylism
airway obstruction
hepatosplenomegaly
NO corneal clouding
aggressive behaviour
A

hunter - iduronate sulfatase - heparan sulfate, dermatan sulfate - XLR

89
Q

weakness
hypotonia
hypoketotic hypoglyceia

A

systemic primary carnitine deficiency

90
Q 
vomiting
lethargy
coma
seizures
liver dysfunction
hypoketotic hypoglycemia
increased 8-10 carbon fatty acyl carnitines in blood
A

medium-chain acyl-CoA dehydrogenase deficiency

AR

Biochemistry - step (4 decks)

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