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Biochem Flashcards

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1
Q

Signal transduction of alpha1 receptors

A

IP3 –> Ca2

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2
Q

Signal transduction of Beta receptors

A

cAMP –> Protein kinase A

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3
Q

Signal transduction of M1 and M3 recptors

A

IP3 –> Ca2 + protein kinase C

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4
Q

Signal transduction of M2 receptors

A

cAMP

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5
Q

Signal transduction of nicotinic receptors

A

Voltage gated Na Ca and K channel

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6
Q

Cytokines that induce systemic inflammatory response

A

IL 1, IL 6, and TNFa

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7
Q

DNA Pol I

A

Works on the lagging strand, synthesizes 5’ to 3’ and is an exonuclease at 5’ to 3’
Degrades RNA primers

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8
Q

DNA Pol III

A

Works on both lagging and leading strand. Synthesizes 5’ to 3’ but is an exonuclease at 3’ to 5’

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9
Q

Xeroderma pigmentosum

A

deficient endonuclease for thiamine dimer repair due to UV radiation

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10
Q

Base excision repair process

A

Alteration to a single nucleotide usually by carcinogen

Glycolsylase removes altered base
Lyase and endonuclease repair 3’ and 5’ ends
DNA pol adds in new base
Ligase completes the chain

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11
Q

Mismatch repair

A

MutS and MutL recruit Endonuclease to the mismatch which removes the surrounding DNA
DNA pol replaces the sugars and ligase completes the process

Defective in lynch syndrome

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12
Q

Homologous end joining

A

Sister chromosome used as template

Associated with Fanconi anemia and gynecological malignancy

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13
Q

Nonhomologous end joining

A

Many proteins required, no sister chromosome template
increased risk of errors
associated with ataxia telangiectasia

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14
Q

Amatoxins inhibit

A

RNA pol II

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15
Q

Amino acids bind this portion of tRNA

A

3’ acceptor stem sequence CCA

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16
Q

D arm of tRNA

A

binds aminoacyl tRNA synthetase which adds amino acids to tRNA

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17
Q

T arm of tRNA

A

binds the ribosome

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18
Q

Mutations in introns are commonly associated with

A

B thal

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19
Q

E2F

A

Promotes G1 to S phase transition

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20
Q

Rb protein

A

Binds E2F and prevents transition to S phase. When phosphorylated by Cyclin-CDK complex it will release E2F. Mutation can result in retinoblastoma or osteosarcoma.

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21
Q

Cyclin-CDK complex

A

Phosphorylates Rb, releasing E2F and allowing progression to S phase. This action is blocked by p21.
Mutations in Cyclin D1 result in Mantle Cell Lymphoma

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22
Q

p21

A

Prevents Cyclin-CDK from phosphorylating Rb. This action is promoted by p53.

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23
Q

p53

A

Further activates p21’s inhibition of Cyclin-CDK

mutations in p53 are associated with Li-Fraumeni syndrome. DNA damage UP REGULATES p53 to prevent cancer.

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24
Q

I cell disease

A

Defect in N-acetylglucoasminyl-1-phosphotranferase
Proteins become secreted instead of transported to lysosomes

Presentation:
Failure to thrive
Coarse facial features
Cognitive impairment
Corneal clouding
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25
Clathrin
associated with transport between the cell membrane and golgi
26
COP1
transport from golgi to RER
27
COP2
transport from RER to golgi
28
Zellweger syndrome
Dysfunction in peroxisome activity, increased very long chain fatty acids
29
X-linked adrenoleukodystrophy
Impaired transport of very long chain fatty acids to peroxisome Accumulation in brain (cognitive impairment) and adrenal glands (adrenal insufficiency)
30
Desmin
Intermediate filament associated with rhabdomyosarcoma
31
Vimentin
intermediate filament associated with sarcomas
32
GFAP
intermediate filament associated with astrocytomas
33
Neurofilaments
intermediate filaments associated with neuroblastomas.
34
Scurvy mechanism
VitC is required for the hydroxylation of pro alpha chains of collagen
35
Osteogenesis imperfecta mechanism
Faulty assembly of 3 collagen pro alpha chains into procollagen
36
Osteogenesis imperfecta
Autosomal Dominant COL1A1/COL1A2 gene mutations Multiple fx, blue sclera, hearing loss, abnormal teeth
37
Ehlers-Danlos mechanism
Deficiency of procollagen peptidase or lysyl oxidase | Decreased cross linking of collagen
38
Menkes Dz
Decreased Cu absorption which is a cofactor of lysyl oxidase resulting in decreased cross linked collagen - Brittle hair - Hypotonia - Growth Restriction
39
Marfan mechanism
Fibrillin 1 is a scaffold protein for elastin
40
Hexokinase
Converts glucose to G6P Present in most tissue, not Beta cells or liver Not induced by insulin Low Km, Low Vmax
41
Glucokinase
``` Converts glucose to G6P Found in B cells and liver Induced by insulin High Vmax High Km ```
42
Phosphofructokinase-2
Converts F6P to F2,6BP | Upregulated by insulin
43
Phosphofuctokinase-1
Converts F6P to F1,6BP Upregulated by F26BP Downregulated by Citrate and ATP
44
Fructose 2,6 Bisphosphatase
Converts F26BP to F6P | Upregulated by Glucagon
45
Fructose 1,6 Bisphosphatase
Converts F16BP to F6P | Inhibited by F26BP
46
BPG mutase
converts 13BPG to 23BPG takes place in RBCs when O2 levels are low 23BPG decreases Hb affinity for oxygen
47
2,3 BPG phosphatase
Converts 23BPG to 3 phosphoglycerate | After recovery from low oxygen state, returns 23BPG to glycolysis
48
Pyruvate Kinase
Converts phosphoenolpyruvate to pyruvate Produces ATP Deficiency results in hemolysis
49
4 Molecules pyruvate can be converted into
Alanine Oxaloacetate Acetyl-CoA Lactate
50
Lactate dehydrogenase
Converts pyruvate into Lactate | Requires NADH, Niacin
51
Pyruvate Dehydrogenase
Converts Pyruvate to Acetyl Coa Inhibited by NADH and AcetylCoa Requires NAD, Thiamine (B1), Riboflavin (b2), Niacin(B3), and Pantothenic acid (B5)
52
Pyruvate carboxylase
converts pyruvate to oxaloacetate Requires Biotin promoted by AcetylCoA
53
Citrate synthase
converts Acetyl CoA and Oxaloacetate to Citrate | Inhibited by ATP
54
Isocitrate dehydrogenase
``` Converts Isocitrate and NAD to a-Ketogluterate, NADH, and CO2. Requires Niacin (B3) ```
55
a-Ketoglutarate dehydrogenase
Converts a-ketoglutarate and NAD to Sucinyl-CoA, NADH, and CO2 Activated by Ca2+ in skeletal muscle Requires B1, B2, B3, and B5
56
Cytochrome C oxidase
Complex 4 of the ETC | Fe goes between 2+ and 3+ states making it a target for CN- (3+) and CO (2+) poisoning.
57
PEPCK
Converts oxaloacetate to Phosphoenolpyruvate requires GTP used in Gluconeogenesis
58
Von Gierke disease
Deficiency of Glucose 6 phosphatase Hypoglycemia and hepatomegaly and lactic acidosis Gierke breaks Gluconeogenesis
59
a-1,4 glucosidase
Converts glycogen into glucose within lysosmes | Deficient in Pompei Dz
60
Pompe Disease
``` Deficient a-1,4 glucosidase Build up of glycogen within lysosomes Cardiomegaly, hepatomegaly, and hypotonia Normal blood sugars "PomPe breaks the PumP" 4 Ps = 1.4 ```
61
Glycogen Phosphorylase
Cleaves alpha-1,4 links in glycogen Deficient in McArdles Dz Activated by Ca2+, AMP, and cAMP
62
McArdle Disease
Deficient glycogen phosphorylase in skeletal muscle Muscle cramps, weakness, rhabdomyoslysis Liver unaffected "McArdle breaks the Muscle"
63
a-1,6-glucosidase
Breaks the branches of glycogen | deficiency causes Cori Dz
64
Cori Disease
Deficient a-1,6-glucosidase Accumulation of glycogen causes hepatomegaly, hypotonia, and hypoglycemia. Compensation by fat metabolism causes ketoacidosis Cori breaks the Corner
65
Fructokinase
Converts fructose to F1P | Deficient in Essential fructosuria
66
Essential Fructosuria
Deficiency of fructokinase relatively benign as Fructose can be converted to F6P by hexokinase Detected by copper reduction test
67
Aldolase B
Converts F1P to dihydroxyacetone phosphate and glyceraldehyde Deficient in Fructose intolerance
68
Fructose intolerance
Deficient Aldolase B Accumulation of F1P within cells Hypoglycemia, hepatomegaly, and liver failure detected with copper reduction test
69
Polyol Pathway
Conversion of glucose into sorbitol into fructose Increase in hyperglycemia soribitol can be damaging to the eyes causing cataracts.
70
Lactase
Converts lactose to glucose and galactose | deficient in lactose intolerance
71
Galactokinase
Converts galactose to G1P | Deficiency causes accumulation of galactitol which can cause infantile cataracts
72
Galactose-1-phosphate uridyltransferase
Convers Galac-1-P to Glucose 1 P | Deficiency causes classic galactosemia.
73
classic galactosemia
Deficient Gal1P uridyltransferase Accumulation of Galac1P causes liver damage, cataracts, and hypoglycemia. These patients are also at an increased risk of e coli sepsis due to preference of galactose
74
G6P dehydrogenase
Converts G6P to 6 phosphogluconate Part of the PPP Creates NADPH Deficiency causes hemolysis
75
NADPH
Created in PPP Used in FA, steroid, and cholesterol synthesis Used in production in glutathione for oxidative damage reduction Used in oxidative burst
76
Transketolase
PPP Converts Fructose 6 phosphate to ribose 5 phosphate Preserves PPP in those with G6PD deficiency
77
Carnitine shuttle
Combination of Carnitine and Acyl CoA during fatty acid metabolism allows the Acyl CoA to enter the mitochondria
78
Acyl-CoA Dehydrogenase
Converts Acyl CoA eventually into Acetyl-CoA Creats FADH2 and NADH Deficient in Medium chanin acyl-CoA dehydrogenase deficiency (MCAD)
79
Systemic primary carnitine deficiency
Low carnitine, impairing carnitine shuttle Hypoglycemia (Acetyl CoA not made, cannot promote gluconeogenesis) Hypokentonia due to lack of B oxidation Accumulation of long chain fatty acids in liver and brain
80
Medium chain acyl CoA dehydrogenase Deficiency
Impaired beta oxidation Hypoketotic, hypoglycemia Liver damage, encephalopathy Carnitine levels are normal.
81
Ethanol metabolism (NADH) effects
Metabolism of etoh causes an accumulation of NADH This causes an inhibition of the TCA cycle AcetylCoA from EtOh is shunted to ketone bodies High NADH also promotes pyruvates conversion to lactate High NADH also inhibits the breakdown of fatty acids, causing fatty liver.
82
Vitamin D metabolism step 1
7 dehydrocholesterol is converted to Vitamin D3 (Cholecalciferol) by UV light
83
Vitamin D metabolism step 2
Cholecalciferol (Light or diet) is converted to 25 Hydroxvyvitamind D by 25 hydroxylase in the liver
84
VitD metabolism step 3
25 hydroxyvitamind D is converted to 1,25 dihydroxyvitamin D by 1 alpha hydroxylase in the kidney This process is regulated by PTH
85
Effects of 1,25 dihydroxyvitamin D
Increases bone mineralization, increases calcium absorption in SI, increases calcium and phosphate reabsorption in kidneys, decreases PTH secretion
86
ApoB48
Only found on chylomicrons, allows entering of enterocytes
87
ApoC-II
Transfered to chylomicron by HDL | Cofactor for LPL
88
ApoE
Transfered to chylomicron by HDL Facilitates binding to the hepatic remnant receptors Found on HDL, chylomicros, HDL, VLDL, IDL
89
Lipoprotein lipase
Frees fatty acids from Chylomicros and VLDL converting them into Chylomicron remnants and IDLs
90
ApoB100
Allows VLDL to exit the liver and LDL to re enter the liver
91
Fibrates, Niacin, Fish oil
all block excretion of VLDL by the liver
92
Hepatic lipase
Converts IDL to LDL, freeing fatty acids and removing ApoE
93
Abetalipoproteinemia
Lack of ApoB100 and ApoB48 Inability to secrete VLDL and chylomicrons Steatorrhea, fat soluble vitamin deficiency, acanthocytosis
94
Acanthocytosis
lack of lipids in RBC membrane, making them appear spiny
95
Famililial hyperchylomicronemia (type I)
Deficiency ApoC-II Increased Chylomicrons and VLDL Labs: TGs
96
PCSK9 inhibitors
Decrease LDL receptor degradation on the liver, allowing for increased LDL reabsorption evolocumab
97
Lecithin choldesterol acyl transferase
Allows HDL to absorb cholesterol
98
Cholesterol ester transfer protein
Allows transfer of cholesterol from HDL to VLDL and LDL
99
Familial hypercholesterolemia (Type II)
ApoB 100 Defect or LDL receptor defect LDL cannot re enter the liver Labs: LDL
100
Familial dysbetalipoproteinemia (Type III)
Defect in ApoE3 and ApoE4 Chylomicrons, VLDL, IDL cannot enter the liver Labs: Tgs, VLDL, IDL
101
Familial hypertriglyceridemia (Type IV)
Overproduction of VLDL | Labs: TG
102
Cystathionine synthase
Converts homocysteine to cystathionine reqiuires B6 Deficient in homocysteinuria
103
Homocysinuria
Usually due to a deficiency in cystathionine synthase elevated homocysteine in the urine Cysteine becomes an essential AA ID, hypercoag, ectopia lentis, and marfanoid habitus B6 can improve symptoms
104
Methionine synthase
Converts homocysteine to methionine. Requires 5-methyl THF Requires B12 Indirectly requires folate for turnover of THF Deficiency can be an alternative cause of homocystinuria
105
Uses of Methionine
Can be made into SAM for methylation reactions | Can be converted to propionyl Coa --> MMA --> Succinyl CoA (requires folate)
106
PRPP amidotransferase
Used in purine synthesis to create IMP which can become AMP or GMP
107
UMP Synthase
Converts PRPP and orotic acid to UMP for pyrimadine synthesis Deficient in Orotic aciduria
108
Orotic Aciduria
Deficient UMP synthase Megaloblastic anemia No hyperammonemia Tx: Uridine
109
Thymidylate Synthase
Converts dUMP to dTMP Requires 5,10-methylene THF Indirectly requires folate Inhibited by 5FU
110
Dihydrofolate Reductase
Converts DHF to THF requires folate Inhibited by methotrexate, Primethamine, and TMP
111
HGPRT
Converts Hypoxanthine/Guanine and PRPP to IMP or GMP | Deficiency causes lesch-nyhan syndrome
112
Adenosine daminase
Converts adenosine to Inosine | Deficiency causes SCID (adenosine metabolites are toxic to T cells)
113
Lesch-Nyhan Syndrome
Deficient HGPRT | Gout, Self mutilation, and ID
114
Carbamoyl phosphate synthase I
Combines NH3 CO2 and ATP to form Carbamoyl Phosphate
115
Orinithine transcarbamylase
Converts carbamoyl phosphate and ornithine to citrulline
116
Ornithine transcarbamylase deficiency
Decreased urea cycle activity Hyperammonemia Increased Orotic acid
117
NH3 effects on the nervous system
Glutamine is converted to glutamate in presynaptic neurons. Glutamate is used as an excitatory neurotransmitter Once released, glutamate is eventually reabsorbed by a nearby astrocyte and combined with NH3 from the bllod to be converted back to Glutamine. This is then returned to the presynpatic neuron. In situations with increased NH3 in the blood, increased amounts of glutamine are created in astrocytes. This acts as an osmotic agent, drawing water into the astrocyte. When the astrocyte is swollen it is no longer able to transfer its glutamine to the presynaptic neuron.
118
Connexins
Gap junctions
119
Claudins, occludin
Tight junction
120
Cadherins
Adherens junction
121
desmogleins, desmoplakins
Desmosomes
122
Integrins
Hemidesmosomes
123
Maple syrup urine disease
Deficiency in branched chain a ketocaid dehydrogenase complex Defective metabolism of isoleucine leucine and valine Cannot produce proprionyl CoA B1 B2 B3 B5 accumulation of alpha keto acids ID, seizures, irritability Thiamine can improve symptoms
124
Phenylalanine hydroxylase
COnverts phenylalanine to tyrosine Requires BH4 Deficiency of this is one cause of PKU
125
Dihyrobiopterin reductase
Converts BH2 to BH4 | Deficiency of this is one cause of PKU
126
PKU
Defiency of Phenylalanine hydroxylase or Dihydrobiopterin reductase Results in deficiency of neurotransmitters (dopamine, epi, NE) Tyrosine becomes essential
127
Tyrosinase
Converts DOPA to melanin | Deficiency causes albinism
128
Homogentisic acid dioxygenase
Converts homogentisate to maleylacetoacetate | Deficient in Alkaptonuria
129
Alkaptonuria
Homogentisic acid dioxygenase deficiency Homogentisic acid accumulates in the connective tissue (ears and sclera, joint pain) and in the urine. When urine is exposed to air it will turn black.
130
Fabry Dz
lack of a-galactosidase A accumulation of Ceramide Trixhexoside Palm and sole neuropathy, anhydrosis, renal and CV failure in adulthood, angiokeratomas X linked recessive Fa br A
131
Niemann Pick Dz
Deficient sphingomyelinase accumulation of sphingomyelin Weakness, Chery red spot, HSM, foam cells Autosomal recessive
132
Tay Sachs Disease
``` Deficient Hexoasaminidase A Accumulation of GM2 Ganglioside Weakness cherry red spot lysosomes with onion skin autosomal recessive A GANG of six jews ```
133
Gaucher Disease
``` Glucocerebrosidase deficiency Accumulation of glucocerebroside Bone dz, lipid laden macrophages, pancytopenia Autosomal recessive gaUcher ```
134
Arginase Deficiency
Normally converts Arginine to ornithine and urea. | Causes spastic diplegia, abnormal movements, and growth delay. No/mild hyperammonemia.
135
Huntingtin protein
In Huntington dz there is a gain of function which causes increased histone deacetylation, which silences genes necessary for neuron survival
136
AAT
AAT is the primary inhibitor of neutrophil and macrophage elastin degradation protein Results in panacinar empysema Accelerated by smoking and 2nd hand smoke
137
Gq G protein
IP3 and DAG --> PKC | Used by H1, a1, va,M1, and M3 (HAV 1 M&M)
138
Gi G protein
Decreases cAMP | Used by M2, a2, D2 (MAD 2)
139
Gs G protein
Increases cAMP -->PKA | used by everything besides HAV1 M&M and MAD 2
140
cGMP
ANP BNP NO and EDRF activate guanylate cyclase creating cGMP cGMP increased Protein Kinase G Protein Kinase G causes vasodilation
141
Receptor Tyrosine Kinases
Insulin, IGF-1, EGF, PDGF, FGF | Act on RAS/MAP kinase pathway
142
Nonreceptor tyrosine kinases
IL-2, IL-6, prolactin, thrombopoietin, erythropoeitin, GH, GCSF Acts on the JAK/STAT Pathway
143
alpha 1
Mydriasis, vasocontriction
144
alpha 2
Decrease NE release, decrease aqueous humor production
145
Beta 1
Increase heart rate, increase contractility, increase Renin
146
Beta 2
Vasodilation in Skeletal muscles, bronchodilation, increased aqueous humor production
147
M3 sympathetic
Sweating, only sympathetic M receptor
148
M3 parasympathetic
Miosis, lens accomodation, bronchoconstriction, increased gastric acid, increased salivation, increased parastalsis, bladder contraction
149
M2
Decreased HR, decreased contractility
150
H1
Increased mucous production, bronchoconstriction, and vasodilation
151
H2
Increased HCl secretion
152
V1
Vasoconstriction
153
V2
Increased aquaporins in collecting tubule --> increased H20 reabsorption
154
GLUT4
Transporter found in myocytes and adipose tissue | Responsive to insulin
155
Ornithine shuttle
Transport of proteins into mitochondria for urea cycle

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