Biochemistry High Yields Flashcards
(105 cards)
1
Q
mRNA stop codons
A
UGA, UAA, UAG
“U Go Away”
“U Are Away”
“U Are Gone”
2
Q
Rough Endoplasmic Reticulum
A
Site of synthesis of secretory proteins and of N-linked oligosaccharide addition to many proteins
Goblet cells of small intestines and plasma cells are rich in RER
3
Q
Smooth Endoplasmic Reticulum
A
Site of steroid synthesis and detoxification of drugs and poisons; Lacks surface ribosomes
Liver hepatocytes and adrenal cortex and gonads are rish in SER
4
Q
Golgi
A
Distribution center for proteins and lipids from ER to the vesicles and plasma membrane; Modifies N-oligosaccharide on aspargine; Adds O-oligosaccharides on serine and threonine; Adds mannose-6-phosphate to proteins for trafficking to lysosomes
5
Q
I-Cell Disease
A
Inherited lysosomal storage disorder; defect in N-acetylglucosaminyl-1-phosphotransferase –> failure of golgi to phosphorylate mannose residues (ie. decreased mannose-6-phosphate) on glycoproteins –> proteins secreted extracellularly rather than delivered to lysosomes
Coarse facial features (gargoyl), clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes, increased acid hydrolases and glycosylases, hyperplastic gums
6
Q
Drugs that Act on Microtubules
A
Mebendazole, Griseofulvin, Colchicine, Vincristine/Vinblastine, Paclitaxel
7
Q
Type I Collagen
A
Bone, skin, tendon, cornea; Osteogenesis Imperfecta
8
Q
Type II Collagen
A
Cartilage
9
Q
Type III Collagen
A
Reticulin - skin, blood vessels, uterus, granulation tissue; Vascular type of Ehlers-Danlos
10
Q
Type IV Collagen
A
Basement membrane, basal lamina, lens; Alport syndrome, Goodpasture syndrome
11
Q
Gq
A
H1, Alpha1, V1, M1, M3 - “HAVe 1 M&M”; Phospholipase C –> IP3/DAG –> Ca2+/PKC
12
Q
Gs
A
Beta1, Beta2, D1, H2, V2; Adenylyl cyclase –> cAMP, PKA
13
Q
Gi
A
M2, Alpha2, D2 - “MAD 2s”; decrease cAMP
14
Q
Dynein
A
Retrograde to microtubule (+ –> -)
15
Q
Kinesin
A
Anterograde to microtubule (- –> +)
16
Q
GFAP Stain
A
Neuroglial cells
17
Q
Collagen Synthesis
A
1) Synthesis (RER) - Translation of collagen alpha chains
2) Hydroxylation (RER) - hydroxylation of specific proline and lysine residues (requires Vit. C)
3) Glycosylation (RER) - formation of procollagen via hydrogen and sulfide bonds (triple helix)
4) Exocytosis into extracellular space
5) Proteolytic processing - cleavage of disulfide rich terminal regions –> insoluble tropocollagen
6) Cross-linking - to make collagen fibrils
* Glycine is predominant AA along with lysine and proline
18
Q
Ehlers Danlos
A
Problem with cross-linking of collagen
19
Q
Southern Blot
A
DNA with DNA probe
20
Q
Northern Blot
A
RNA with DNA probe; useful for studying mRNA levels which are reflective of gene expression
21
Q
Western Blot
A
Protein with antibody probe
22
Q
Southwestern Blot
A
Identifies DNA-binding proteins using labeled oligonucleotide probes
23
Q
X-Linked Recessive Disorders
A
Bruton agammaglobulinemia; Wiskott-Aldrich syndrome; Fabry disease; G6PD deficiency; Ocular albinism; Lesch-Nyhan; Duchenne; Hemophilia, Ornithine transcarbamylase deficiency
24
Q
Trinucleotide Repeat Expansion Diseases
A
Fragile X - CGG
Friedreich Ataxia - GAA
Huntington - CAG
Myotonic Dystrophy - CTG
25
Chr. 3
von Hippel Lindau, Renal cell carcinoma
26
Chr. 4
ADPKD with PKD2 defect; Huntington disease
27
Chr. 5
Cri-du-chat syndrome, FAP
28
Chr. 7
Williams syndrome; CF
29
Chr. 9
Friedreich Ataxia
30
Chr. 11
Wilms Tumor
31
Chr. 13
Patau syndrome, Wilson Disease
32
Chr. 15
Prader Willi, Angelman Syndrome
33
Chr. 16
ADPKD with PKD1 defect
34
Chr. 17
NF-1
35
Chr. 18
Edwards Syndrome
36
Chr. 21
Down Syndrome
37
Chr. 22
NF-2; DiGeorge syndrome
38
Fat Soluble Vitamins
A, D, E, K; Malabsorption with CF or Celiac
39
Vit B1 (Thiamine) Reactions
Pyruvate Dehydrogenase (links glycolysis to TCA)
Alpha-Ketoglutarate Dehydrogenase (TCA cycle)
Transketolase (HMP Shunt)
Branched Chain Ketoacid Dehydrogenase
40
Vit B2 (Riboflavin)
Component of flavins FAD and FMN used in redox rxns.
41
Vit. B3 (Niacin)
Constituent of NAD+ and NADP+; Derived from tryptophan
42
Vit. B5 (Pantothenic Acid)
Essential component of coenzyme A and fatty acid synthase
43
Vit B6 (Pyridoxine)
Converted to pyridoxal phosphate, a cofactor in transamination, decarboxylation and glyocogen phosphorylase;
Synthesis of cystathionine, heme, niacin, histamine, 5-HT, Epi, NE, Dopamine and GABA
*Isoniazide therapy/OCPs can lead to peripheral neuropathy, convulsions etc.
44
Vit B7 (Biotin)
Cofactor for carboxylation enzymes:
- Pyruvate carboxylase: pyruvate --> oxaloacetate (gluconeogenesis)
- Acetyl-CoA carboxylase: acetyl CoA --> malonyl CoA (FA synthesis)
- Propionyl-CoA carboxylase: propionyl-CoA --> methylmalonyl CoA (Odd carbon FA synthesis)
45
Vit B9 (Folate)
Converted to THF, a coenzyme for 1-carbon transfer/methylation reactions
Deficiency can be caused by: phenytoin, sulfonamides, methotrexate
Labs in deficiency: increased homocystein and normal methylmalonic acid
46
Phosphofructokinase-1
Glycolysis
| AMP +, F-2,6-bisphosphate +, ATP - , citrate -
47
Fructose-1,6-bisphosphate
Gluconeogenesis
| ATP +, Acetyl-CoA +, AMP -, F-2,6-bisphosphate -
48
Isocitrate Dehydrogenase
TCA Cycle
| ADP +, ATP -, NADH -
49
Glycogen Synthase
Glycogenesis
| G-6-P +, Insulin +, cortisol +, Epi -, Glucagon -
50
Glycogen Phosphorylase
Glycogenolysis
| Epi +, Glucagon +, AMP +, G-6-P -, Insulin -, ATP -
51
Glucose-6-Phosphate Dehydrogenase (G6PD)
HMP Shunt
| NADP+, NADPH -
52
Carbamoyl Phosphate Synthetase II
De Novo Pyrimidine Synthesis
| ATP+, UTP-
53
Acetyl-CoA Carboxylase (ACC)
Fatty Acid Synthesis
| Insulin +, Citrate +, Glucagon -, Palmitoyl-CoA -
54
Glutamine-Phosophoribosylpyrophosphate Amidotransferase
De Novo Purine Synthesis
| AMP-, Inosine Monophosphate-, GMP-
55
Carbamoyl Phosphate Synthetase I
Urea Cycle
| N-acetylglutamate+
56
Carnitine Acyltransferase I
Fatty Acid Oxidation
| Malonyl-CoA-
57
HMG-CoA Synthase
Ketogenesis
58
HMG-CoA Reductase
Cholesterol Synthesis
| Insulin +, Thyroxine +, Glucagon -, Cholesterol -
59
Pyruvate Carboxylase
Pyruvate --> Oxaloacetate
Requires biotin and ATP; Activated by Acetyl-CoA
In mitochondria
60
Phosphoenolpyruvate Carboxykinase
Oxaloacetate --> Phosphoenolpyruvate
Requires GTP
In cytosol
61
Fructose-1,6-Bisphosphatase
F-1,6-bisphosphate --> F-6-P
Citrate+, F-2,6,-bisphosphate -
In cytosol
62
G-6-P
G-6-P--> glucose
| In ER
63
Essential Fructosuria
Defect in fructokinase
| Symptoms: asymptomatic except fructose appears in blood and urine
64
Fructose Intolerance
Defect in Aldolase B; F-1-phosphate accumulates --> decrease in available phosphate --> inhibition of glycogenolysis and gluconeogenesis
Symptoms present after consumption of fruit, juice or honey
Urine dipstick -; reducing sugar can be detected in urine
Symptoms: hypoglycemia, jaundice, cirrhosis, vomiting
Tx: decrease intake of fructose and sucrose
65
Galactokinase Deficiency
Deficiency of galactokinase; Galactitol accumulates if galactose is present in diet
Symptoms: galactose appears in blood and urine; infantile cataracts; may present as failure to track objects or to develop a social smile
66
Classic Galactosemia
Absence of galactose-1-phosphate uridyltransferase;
Damage caused by accumulation of toxic substances (including galactitol, which accumulates in the lens of the eye)
Symptoms: failure to thrive, jaundice, hepatomegaly, infantile cataracts, intellectual disability
Tx: exclude galactose and lactose
67
Essential AAs
Glucogenic: Methionine, Valine, Histidine
Glucogenic/Ketogenic: Isoleucine, Phenylalanine, Threonine, Tryptophan
Ketogenic: Leucine, Lysine
68
Ornithine Transcarbamylase Deficiency
X-linked recessive; Interferes with body's ability to eliminate ammonia; Excess carbmoyl phosphate is converted to orotic acid
Findings: increased orotic acid in blood and urine, decreased BUN, symptoms of hyperammonemia; No megaloblastic anemia (unlike Orotic aciduria)
69
PKU
Decreased phenylalanine hydroxylase or tetrahydrobiopterine cofactor
Increased phenylalanine --> excess phenylketonse in urine
Findings: intellectual disability, growth retardation, seizures, fair skin, eczema, musty body odor
Tx: decrease phenylalanine and increase tyrosine in diet
70
Maple Syrup Urine Disease
Blocked degradation of branched amino acids (Isoleucine, Leucine, Valine) due to decreased alpha-ketoacid dehydrogenase; Causes increased alpha-ketoacids in the blood (esp. leucine)
Causes severe CNS defects, intellectual disability and death
Tx. Thiamine supplementation and restriction of branched AAs
"I Love Vermont Maple Syrup from trees with branches"
71
Homocystinuria
Types:
- cystathionine synthase deficiency
- decreased affinity of cystathionine synthase for pyridoxal phosphate
- homocysteine methyltransferase deficiency
Findings: increased homocysteine in urine, intellectual disability, osteoporosis, marfanoid habitus, kyphosis, lens subluxation, thrombosis and atherosclerosis (stroke and MI)
72
Glycogen Breakdown Enzymes
1) UDP-glucose pyrophosphorylase
2) Glycogen synthase
3) Branching enzyme
4) Glycogen phosphorylase
5) Debranching enzyme (4-alpha-D-glucanotransferase)
6) Debranching enzyme (alpha-1,6-glucosidase)
73
Orotic Aciduria
Inability to convert orotic acid to UMP (de novo pyrimidine synthesis pathway) because of defect in UMP synthase;
Presents as failure to thrive, developmental delay and megaloblastic anemia refractory to folate or B12; No hyperammonemia (unlike ornithine transcarbamylase deficiency); Orotic acid in urine
Tx: uridine monophosphate to bypass mutated enzyme
74
Von Gierke Disease
G-6-phosphatase deficiency
Findings: hepatomegaly, hypoglycemia, severely increased glycogen in liver, increased blood lactate (lactic acidosis), increased triglycerides, increased uric acid (gout), short stature, doll-like facies, protruding abdomen, hepatic steatosis
Tx. Frequent oral glucose/cornstarch; avoidance of fructose and galactose
75
Pompe Disease
Lysosomal alpha-1,4-glucosidase (acid maltase) deficiency leading to increased glycogen accumulation
Findings: cardiomegaly, hypertrophic cardiomyopathy, exercise intolerance, NO hepatomegaly, NO hypoglycemia, early death
"Pompe trashes the pump"
76
Cori Disease
```
Debranching enzyme (alpha-1,6-glucosidase) deficiency
Milder form of Von Gierke (hypoglycemia, hypertriglyceremia, ketoacidosis, hepatomegaly) with normal blood lactate levels; Accumulation of abnormally short outer dextrin-like structures in cytosol of hepatocytes without histopathological fatty infiltration of liver; Can also effect muscles
Gluconeogenesis is intact
```
77
McArdle Disease
Skeletal muscle glycogen phosphorylase (myophosphorylase) deficiency
Findings: Increase glycogen in muscle, but cannot be broken down --> painful muscle cramps, myoglobinuria (red urine) with strenuous exercise and arrythmia from electrolyte abnormalities
Blood glucose levels typically normal
Tx. with vit B6
78
Fabry Disease
Alpha-galactosidase A deficiency leading to accumulation of Ceramide trihexoside (XR)
Findings: Peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease
79
Gaucher Disease
Glucocerebrosidase (beta-glucosidase) deficiency leading to accumulation of Glucocerebroside (AR)
Findings: hepatosplenomegaly, pancytopenia, osteoporosis, aseptic necrosis of femur, bone crises, Gaucher cells (lipid--laden macrophages resembling tissue paper)
Tx. Recombinant glucocerebrosidase
80
Niemann-Pick Disease
Sphingomyelinase deficiency leading to accumulation of Sphingomyelin (AR)
Findings: Progressive neurodegeneration, hepatosplenomegaly, foam cells (lipid-laden macrophages), cherry red spot on macula (retinal pallor sparing macula), sphingomyelinase in histiocytes (sea blue), Zebra bodies (lamellar lipid deposits)
More common in Ashkenazi Jews
81
Tay-Sachs Disease
Hexosaminidase A deficiency leading to accumulation of GM2 ganglioside (AR)
Findings: progressive neurodegeneration, developmental delay, cherry red spot on macula, lysosomes with onion skin, NO hepatosplenomegaly, blindness
82
Krabbe Disease
Galactocerebrosidase deficiency leading to accumulation of glactocerebroside, psychosine (AR)
Findings: peripheral neuropathy, developmental delays, optic atrophy, globoid cells
83
Metachromatic Leukodystrophy
Arylsulfatase A deficiency leading to accumulation of Cerebroside sulfate (AR)
Findings: Central and peripheral demyelination with ataxia and dementia
84
Hurler Syndrome
Alpha-L-iduronidase deficiency leading to accumulation of Heparan sulfate, dermatan sulfate
Findings: developmental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly
85
Hunter Syndrome
Iduronate sulfatase deficiency leading to accumulation of Heparan sulfate, dermatan sulfate
Findings: mild Hurler + aggressive behavior, NO corneal clouding, kyphosis, short stature, vascular and ischemic heart disease
86
Systemic Primary Carnitine Deficiency
Defect in transport of LCFAs into mitochondria --> toxic accumulation
Findings: weakness, hypotonia, hypoketotic hypoglycemia
Decreased acetoacetate and beta-hydroxyburyrate
87
Medium-Chain Acyl-CoA Dehydrogenase Deficiency
AR disorder of fatty acid oxidation; Decreased ability to break down fatty acids into acetyl-CoA --> accumulation of 8-10 Carbon fatty acyl carnitines in blood and hypoketotic hypoglycemia
Presents: in infancy or early childhood with vomiting, lethargy, seizures, coma and liver dysfunction; can lead to sudden death
88
Ketone Urine Test
Does not detect Beta-hydroxybutyrate
89
Apolipoprotein E
Mediates remnant uptake;
| Chylomicron, chylomicron remnant, VLDL, IDL, HDL
90
Apolipoprotein A-I
```
Activates LCAT (cholesterol esterification)
Chylomicron, HDL
```
91
Apolipoprotein C-II
Lipoprotein lipase cofactor
| Chylomicron, VLDL, HDL
92
Apolipoprotein B-48
Mediates chylomicron secretion
| Chylomicron, chylomicron remnant
93
Apolipoprotein B-100
Binds LDL receptor
| VLDL, IDL, LDL
94
Chylomicron
Delivers dietary TG to peripheral tissue; Delivers cholesterol to liver in form of remnants, which are mostly depleted of their TGs; Secreted by intestinal epithelial cells
95
VLDL
Delivers hepatic TG to peripheral tissue; secreted by liver
96
IDL
Formed in the degradation of VLDL; delivers TG and cholesterol to liver
97
LDL
Delivers hepatic cholesterol to peripheral tissues; Formed by hepatic lipase modification of IDL in peripheral tissue. Taken up by target cells via receptor-mediated endocytosis
98
HDL
Mediates reverse cholesterol transport from periphery to liver; acts as repository for Apolipoproteins C and E (needed for chylomicron and VLDL metabolism); Secreted by both liver and intestines; Alcohol increases synthesis
99
Hyper-Chylomicronemia
Increased Chylomicrons, TG, cholesterol in blood
Lipoprotein lipase deficiency or altered apolipoprotein C-II
Causes pancreatitis, hepatosplenomegaly, erruptive/pruritic xanthomas; No increased risk of atherosclerosis; Creamy layer in supernatant
100
Familial Hypercholesterolemia
Increased LDL, cholesterol
Absent of defective LDL receptors
Causes accelerated atherosclerosis, tendon xanthomas, corneal arcus
101
Hypertriglyceridemia
Increased VLDL, TG
Hepatic overproduction of VLDL
Hypertriglyceridemia, acute pancreatitis
102
RNA Pol I
rRNA (ricin poisoning effects this)
103
RNA Pol II
mRNA (amatoxins from mushrooms effect this)
104
RNA Pol III
tRNA
105
Sickle Cell Mutation
Valine for glutamic acid
