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0. Step Ib > Biochem - all pathways > Flashcards

Biochem - all pathways Flashcards

1
Q

Pompe Disease

signs?

enzyme defect?

A

severe cardiomeagly, hepatomeagly, macroglossia, hypotonia, mental retardation, glycogen accumulation in lysosomes

∆ alpha-glucosidase/acid maltase - converts branched glycogen -> glucose in lysosomes

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2
Q

McArdle Disease

signs?

enzyme defect?

A 
increased muscle glycogen
sx occurs w/ exercise
- weakness + fatigue, little to no rise in blood lactate
- myoglobinuria
- arrhythmias + electrolyte ∆s

∆ glycogen phosphorylase - converts branched glycogen -> limit dextrans

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3
Q

Cori Disease

signs?

enzyme defect?

A

accumulation of small chain dextrin-like material in cytosol
hypoglycemia
hyperTg
ketoacidosis
hepatomeagly
(basically a milder version of Von-Gierke but with normal lactate levels)

∆ debranching enzyme - converts limit dextrans -> glycogen

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4
Q

RA: ∆ alpha-glucosidase/acid maltase

A

Pompe Disease

converts branched glycogen -> glucose in lysosomes

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5
Q

RA = ∆ glycogen phosphorylase

A

McArdle Disease

converts branched glycogen -> limit dextrans

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6
Q

RA = ∆ debranching enzyme

A

Cori disease

converts limit dextrans -> glycogen

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7
Q

Mild Galactosemia

signs?

enzyme defect?

A

galactosuria
cataracts (due to galacticol accumulation) - failure to tract objets, ø social smile
no hepatomeagly

∆ galactokinase - converts galactose -> galactose-1-P

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8
Q

Severe Galactosemia

signs?

enzyme defect?

trmt?

A

failure to thrive
intellectual disability
cataracts
hepatomeagly (due to PO4 depletion, therefore no gluconeogenesis, no glycogenolysis)

∆ G1P uridyltransferase - converts galactose-1-P -> glucose-1-P

Trmt: exclude galactose + lactose

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9
Q

RA = ∆ galactokinase

A

Mild Galactosemia

converts galactose -> galactose-1-P

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10
Q

RA = ∆ G1P uridyltransferase

A

Severe Galactosemia

converts galactose-1-P -> glucose-1-P

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11
Q

RA = trmt: exclude galactose + lactose

A

Severe Galactosemia

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12
Q

Cataracts, retinopathy, and peripheral neuropathy in a patient w/ poorly controlled diabetes should make you think of….

A

sorbitol accumulation in schwann cells, retina, and kidneys due to ∆ sorbitol dehydrogenase (converts sorbitol -> fructose)

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13
Q

Von Gierke

signs?

enzyme defect?

trmt?

A

severe fasting hypoglycemia
hepatomeagly (due to increased glycogen in liver)
increased blood lactate (more gets funneled down)

∆ Glucose-6-phosphatase - converts glucose-6-P -> Glucose

trmt: frequent oral glucose + starch; avoid fructose and galactose

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14
Q

RA = ∆ sorbitol dehydrogenase

A

sorbitol accumulation sorbitol accumulation in schwann cells, retina, and kidneys

converts sorbitol -> fructose

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15
Q

RA = ∆ Glucose-6-phosphatase

A

Von Gierke

converts glucose-6-P -> Glucose

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16
Q

RA = trmt: frequent oral glucose + starch; avoid fructose and galactose

A

Von Gierke

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17
Q

Hemolytic Anemia in PPP

signs?

enzyme defect?

A

hemolytic anemia w/ exposures to oxidative stress (due to øNADPH)

  • sulfa Rx
  • antimalarials
  • infection/free radicals
  • fava beans
  • anti-TB Rx

∆ G6P DH - converts glucose-6-P to 6-phosphogluconate

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18
Q

Essential Fructosuria

signs?

enzyme defect?

A

Fructosemia + fructosuria (reducing agent in urine)

∆ fructokinase - converts fructose -> fructose-1-P

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19
Q

Fructose Intolerance

signs?

enzyme defect?

A

Fructosuria
decreased glycogenolysis + gluconeogenesis (due to decr. P)
sx that occur after consuming fruit juice/honey:
- hypoglycemia
- jaundice
- cirrhosis
- vomiting

∆ Aldolase B - converts fructose-1-P to glyceraldehyde

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20
Q

Hemolytic Anemia in Glycolytic Pathway

signs?

enzyme defect?

A

hemolytic anemia (due to ø glycolysis and ø ATP to maintain RBC structure)

∆ pyruvate kinase - converts PEP -> Pyruvate

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21
Q

RA: ∆ G6P DH

A

Hemolytic anemia due to PPP

converts glucose-6-P to 6-phosphogluconate

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22
Q

RA: ∆ Fructokinase

A

Essential Fructosuria

converts fructose -> fructose-1-P

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23
Q

RA: ∆ Aldolase B

A

Fructose Intolerance

converts fructose-1-P to glyceraldehyde

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24
Q

RA: ∆ pyruvate kinase

A

hemolytic anemia in glycolytic pathway

converts PEP -> Pyruvate

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25
∆ pyruvate carboxylase
downregulation of Citric acid cycle/energy producing capacity of the cell converts Pyruvate -> oxaloacetate
26
∆ pyruvate dehydrogenase signs? trmt?
Lactic acidosis increase serum alanine neurological defects trmt: increase fat, lysine, leucine converts pyruvate -> Acetyl CoA
27
arsenic blocks these two enzymes net ATP?
pyruvate DH alpha-ketoglutarate DH net: 0 ATP
28
Symptoms due to defects in carnitine shuttle
hypoketoic hypoglycemia hyptonia (weakness)
29
∆ Acyl-CoA DH
low fasting glucose
30
Maple Syrup Disease signs? enzyme defect? trmt?
``` CNS defects (retardation) urine that smells like burnt sugar/maple syrup ``` ∆ alpha-keto acid dehydrogenase - converts branched chain a.a. to propionyl CoA trmt: decrease isoleucine, leucine, valine, increase thiamine (B1)
31
Folic acid deficiency
Macrocytic anemia hypersegmented PMN Increased homocysteine
32
Cobalamin deficiency
Macrocytic anemia hypersegmented PMN DCML problems Increased homocysteine + methylmalonyl CoA
33
Homocystinuria signs? enzyme defect? trmt?
``` downward + inward lens displacement kyphosis osteoporosis stroke, MI intellectual disability ``` ∆ homocysteine methyltransferase - 2 reactions: homocystine -> methionine methylmalonyl CoA -> succinyl CoA trmt: pyridoxine
34
RA: ∆ alpha-keto acid dehydrogenase
Maple Syrup Disease converts branched chain a.a. to propionyl CoA
35
RA: ∆ homocysteine methyltransferase
homocystinuria homocystine -> methionine methylmalonyl CoA -> succinyl CoA
36
Ornithine transcarbamylase deficiency signs? enzyme defect? trmt?
increased orotic acid hyperammonemia ø megaloblastic anemia decreased BUN trmt: restrict proteins ∆ = Ornithine transcarbamylase (OTC) - converts urea cycle intermediates -> carbomoyl phosphate
37
Orotic Aciduria signs? enzyme defect? trmt?
needle-shaped orotic acid crystals ø hyperammonemia megaloblastic anemia (hypochromic) hypersegmented nuclei ∆ UMPS (orotidine phosphorribosyl Transferase and Orotidine-5-phosphate decarboxylase) - converts orotic acid -> UMP trmt: uridine
38
Hyperammonemia + increased ornithine
∆ N-acetyl glutamate - cofactor of carbamoyl phosphate synthetase (CPSI), which converts NH3 + CO2 -> carbomoyl phosphate
39
RA: ∆ Ornithine transcarbamylase (OTC)
Ornithine transcarbamylase deficiency converts urea cycle intermediates -> carbomoyl phosphate
40
RA: ∆ orotidine phosphorribosyl transferase
Orotic Aciduria - part of UMPS complex with orotidine-5-phosphate decarboxylase converts orotic acid -> UMP
41
RA: ∆ orotidine-5-phosphate decarboxylase
Orotic Aciduria - part of UMPS complex with orotidine phosphorribosyl transferase converts orotic acid -> UMP
42
difference between CPS I and CPS II? how do you tell if one is deficient over the other?
CPS I - converts NH3 + CO2 to carbomyl phosphate; requires N-acetylglutamate CPS II - converts glutamine + CO2 to carbomyl phosphate w/ CPSI deficiency, you get increased ornithine
43
Lesch-Nyhan signs? enzyme defect? trmt?
self-mutilating behavior excess uric acid trmt: allopurinol, febuxostat ∆ HGPRT - converts guanine/hypoxanthine -> GMP, IMP
44
SCID signs? enzyme defect?
excess ATP decreased lymphocytes decreased DNA synthesis ∆ ADA - converts AMP -> guanine/hypoxanthine
45
RA: ∆ HGPRT
Lesch-Nyhan converts guanine/hypoxanthine -> GMP, IMP
46
RA: ∆ ADA
SCID converts AMP -> guanine/hypoxanthine
47
RA: trmt: allopurinol, febuxostat
Lesch-Nyhan
48
PKU signs? enzyme defect? trmt?
``` ø melanin, pale fair skinned musty body odor eczema seizures, intellectual disability growth retardation increased phenylketones in urine (phenyl-acetate, -lactate, -pyruvate) tyrosine becomes an essential a.a. ``` ∆ phenylalanine hydroxylase - converts phenylalanine -> tyrosine trmt: decrease phenyalanine, increase tyrosine, avoid aspartame
49
Albinism
ø melanin, pale fair skinned ∆ tyrosinase - converts DOPA -> melanin
50
Alkaptonuria signs? enzyme defect?
urine turns dark @ room air brown connective tissue + sclera arthralgia ∆ Homogenistic acid oxidase - converts Homogenistic acid -> maleyacetoacetic acid
51
RA: ∆ phenylalanine hydroxylase
PKU
52
RA: ∆ tyrosinase
Albinism
53
RA: ∆ Homogenistic acid oxidase
Alkaptonuria
54
Sideroblastic anemia
∆ ALAS or B6 (losses inducible by isoniazid) | no B6 -> peripheral neuropathy, convulsions, irritability
55
lead inhibits these two enzymes
ALAD, Ferrochetolase
56
Acute intermittent porphyria signs? enzyme defect? trmt?
painful abdomen port-wine colored urine polyneuropathy (muscle weakness) psychological ∆s trmt: glucose + heme (feeds-back to inhibit ALAS) ∆ Porphobilinogen deaminase - converts porphobilinogen -> Hydroxymethylbilane
57
Porphyria cutanea tarda signs? enzyme defect?
blistering cutaneous photosensitivity ∆ Uroporphyrinogen decarboxylase - converts Uroporphyrinogen III -> Coproporphyrinogen III
58
RA: ∆ porphobilinogen deaminase
converts porphobilinogen -> Hydroxymethylbilane
59
RA: ∆ Uroporphyrinogen decarboxylase
converts Uroporphyrinogen III -> Coproporphyrinogen III
60
RA: trmt: glucose + heme
Acute intermittent porphyria
61
Crigler-Najjar Syndrome signs? enzyme defect? trmt?
jaundice kernicterus (bilirubin deposition in brain) increased unconj. bilirubin. trmt: plasmapheresis and phototherapy ∆ UDP-glucuronosyltransferase - converts bilirubin -> bilirubin diglucuronide, water soluble
62
Gilbert syndrome signs? enzyme defect?
symptomatic or mild jaundice elevated unconj. bilirubin w/o overt hemolysis bilirubin increases w/ fasting and stress. low UDP-glucuronosyltransferase - converts bilirubin -> bilirubin diglucuronide, water soluble
63
Dubin- Johnson syndrome signs? enzyme defect?
Conjugated hyperbilirubinemia black liver defective liver excretion-> obstructive jaundice
64
Rotor syndrome signs? enzyme defect?
mild conjugated hyperbilirubinemia ø black liver decreased liver excretion-> obstructive jaundice, milder version of DJ syndrome
65
RA: ∆ UDP-glucuronosyltransferase
Crigler-Najjar converts bilirubin -> bilirubin diglucuronide, water soluble
66
RA: low UDP-glucuronosyltransferase
Gilbert syndrome converts bilirubin -> bilirubin diglucuronide, water soluble
67
RA: defective liver excretion-> obstructive jaundice
Dubin Johnson syndrome
68
RA: decreased liver excretion-> obstructive jaundice
Rotor syndrome
69
derivative of NO
argnine
70
derivatives of urea
arginine + aspartate
71
derivatives of heme
glycine + succinyl CoA
72
derivatives of creatinine
glycine + arginine + SAM
73
derivatives of GABA
glutamate
74
derivatives of glutathione
glutamate
75
derivatives of pyrimidines
glutamate + aspartate
76
derivatives of purines
glutamate + aspartate + glycine
77
derivatives of histamine
histidine
78
derivatives of dopamine
phenylalanine
79
derivatives of melatonin
tryptophan
80
derivatives of niacin
tryptophan
81
derivatives of thyroxine, melanin
tyrosine
82
Net ATP from aerobic respiration in the heart + liver Net ATP from aerobic respiration in the muscle Net ATP from anaerobic respiration Net ATP from arsenic poisioning
``` 32 = heart + liver 30 = muscle ``` anaerobic = 2 arsenic = 0
83
glucokinase is present in what tissues? hexokinase?
``` glucokinase = liver, ß cells of pancreas hexokinase = all other tissues ```
84
Which gene is associated with maturity-onset diabetes of the young?
Glucokinase
85
How do these affect oxidative phosphorylation? Rotenone, cyanide, antimycin A, CO
all inhibit electron transport, resulting in a DECREASED proton gradient and no ATP synthesis "DRACCO"
86
How does oligomycin affect oxidative phosphorylation?
inhibits ATP synthase, resulting in INCREASED proton gradient and no ATP synthesis
87
How does 2,4-DNP, aspirin, and thermogenin affect oxidative phosphorylation?
increases permeability of the membrane, resulting in decreased proton gradient and increased O2 consumption ATP synthesis stops, but e-transport continues, resulting in heat production
88
essential a.a
isoleucine, phenylalanine, threonine, tryptophan lysine, leucine methionine, histidine, valine "PITT LYed to LUCy about going to the MET w. HIS ex VALerie
89
a.a. in histones
arginine and lysine
90
acidic a.a.
glutamic acid aspartic acid "GLUe is esp (ASP) acidic"
91
basic a.a.
Histidine Lysine Arginine "HIS LYes ARe basic"
92
purpose of Cori cycle? What drug can inhibit this cycle and what happens?
transports lactate to the liver for gluconeogenesis to prevent lactic acidosis in muscles pathway can be inhibited by METFORMIN, resulting in lactic acidosis in patients with renal failure since the kidneys can't handle excess lactic acid
93
purpose of alanine cycle?
shuttles alanine to the liver to make more glucose and to prevent NH3 buildup in muscles
94
pathophysiology of hepatic encephalopathy? sx? trmt?
liver dz (cirrhosis) or urea cycle enzyme deficiencies can result in an excess of NH4, which depletes a-KG, leading to an inhibition of TCA sx: tremor (asterixis), slurring of speech, somnolence, vomiting, cerebral edema, blurring of vision Trmt: limit protein, Benzoate or phenylbutryate (bind a.a. and lead to its excretion) or Lactulose (acidifies GI to trap NH4 for excretion)
95
∆ N-acetylglutamate
required cofactor for CPS I (carbamoyl phosphate synthetase I) leads to HYPERAMMONEMIA increased ornithine (compare to a pure CPSI deficiency)
96
serotonin is derived from which a.a.?
tryptophan
97
niacin is derived from which a.a.?
tryptophan
98
melatonin is derived from which a.a.?
tryptophan
99
histamine is derived from which a.a.?
histidine
100
heme is derived from which a.a.?
glycine
101
porphyrin is derived from which a.a.?
glycine
102
GABA is derived from which a.a.?
glutamate
103
glutathione is derived from which a.a.?
glutamate
104
creatinine is derived from which a.a.?
argninine
105
urea is derived from which a.a.?
argninine
106
NO is derived from which a.a.?
argninine
107
DOPA and dopamine is derived from which a.a.?
phenyalanine (-->tyrosine)
108
melanin is derived from which a.a.?
phenyalanine (-->tyrosine)
109
NE is derived from which a.a.?
phenyalanine (-->tyrosine)
110
Epi is derived from which a.a.?
phenyalanine (-->tyrosine)
111
RA: trmt for PKU
decrease phenyalanine increase tyrosine avoid aspartame
112
Cystinuria enzyme defect? signs? diagnostic test trmt?
∆ PCT + intestinal a.a. transporter for cysteine, ornithine, lysine, and arginine - COLA hexagonal cystine stones urinary cyanide-nitroprusside test trmt: alkalinization (K-citrate or acetazolamide) and chelating agents
113
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0. Step Ib (19 decks)

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