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Biochem facts Flashcards

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1
Q

Amino acids necessary for purine synthesis?

A

GAG
Glycine
Aspartate
Glutamine

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2
Q

What drugs inhibit enzymes of pyrimidine syn;
Ribonucleotide reductase
Thymidalate synthase
DHFR

A 
RR= Hydroxyurea
TS= 5FU
DHFR= MTX, TMP, Pyrimethamine
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3
Q

What drugs inhibit purine synthesis?

A

6-MP
Azathiprine
Ribavirin
Mycophenalate mofetil

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4
Q

Only two amino acids that are coded by only 1 codon?

A

Methionine

Tryptophan

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5
Q 
DNA replication enzyme functions:
Topoisomerase 
DNA pol 3
DNA pol 1
Telomerase
A

Topo =Relieve supercoils
DNApol3= 5->3 synthesis & 3->5 Exonuclease
DNA pol1= Degrades RNA primer and replaces it with DNA
Telomerase= adds DNA 3’ ends of chromosomes to avoid loss during duplication

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6
Q

Enzyme responsible for replacing RNA primers during DNA replication?

A

DNA pol 1

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7
Q

Enzyme that has proofreading capabilities during DNA replication?

A

DNA pol 3

3->5 EXOnuclease

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8
Q

Transition vs Transversion mutation?

A

BOTH Missense or nonsense mutations
Transition= replace purine with purine (opposite also true)
Transversion= Purine with pyrimidine

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9
Q

Nucleotide excision repair?

A

Endonuclease release damaged Bases and DNA pol & Ligase fill in gaps

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10
Q

What disease is caused by defective Endonuclease action?

A

XP ==> Cant fix Thymidine dimers in the MIDDLE of the DNA (hence ENDOnucelase)

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11
Q

Base excision repair?

A

Glycosylase removes damaged bases
Endonuclease cuts DNA
Gaps filled in by DNA pol & Ligase

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12
Q

What disease is caused by defective mismatch repair genes?

A

HNPCC=> so with every new duplication DNA mistmatches are not recognized and repaired.

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13
Q

What disease is caused by mutation in the repair of Double stranded breaks?

A

Ataxia telangiectasia

DNA repair gene mutation

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14
Q

In Eukaryotes what forms:
rRNA
mRNA
tRNA

A

DNA pol 1
DNA pol 2
DNA pol 3
**Numbered according to use of RNA during protein synthesis
**1 RNA pol makes ALL 3RNA in prokaryotes

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15
Q

Amanitin/ mushroom poison inhibits what?

A

DNA pol 2 ==> mRNA synthesis

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16
Q

Autoantibodies against snRNPs are highly specific of what disease?

A

SLE ==> aka Anti-smith antibodies

Anti-U1 RNP = mixed CT disease

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17
Q

Where do AAs bind on the tRNA?

A

3’ CCA site

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18
Q

What antibiotics bind the 30s and inhibit initiation complex formation?

A

Aminoglycosides

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19
Q

Antibiotics that block aminoacyl tRNA from entering acceptor site?

A

Tetratcyclines

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20
Q

Antibiotic that inhibits peptidyl transferase?

A

Chloramphenicol (binds 50s)

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21
Q

Antibiotics that prevent release of unchanged tRNA and thus inhibit translocation?

A

Macrolides

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22
Q

What two signals inhibit G1->S phase transition?

A

p53

Hypophosphorylated Rb

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23
Q

Examples of:
Permanent cells
Stable
Labile

A 
Permanent-= RBC, neuron, skeletal/ cardiac m
Stable = hepatocyte
labile= BM, skin, gut epithelium
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24
Q

What is the site of N-linked oligosaccharide addition to proteins?

A

RER

**Nissel bodies in neuron= RER

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25
Functions of SER?
Steroid synthesis Detoxification **Hepatocytes + Adrenal cortex rich SER supply
26
What adds 0-oligosaccharides on serine residues and mannose-6P to proteins?
GOLGI | **I cell disease**
27
Features of I cell disease?
Enzymes secreted into ECS not lysosomes Coarse face CLouded cornea Gingival hyperplasia
28
What is the function of signal recognition particles?
Traffic proteins from ribosomes to RER by recognizing hydrophobic regions. **Defect= accumulation of proteins in cytosol
29
Cis vs Trans golgi?
Cis=> closer to RER | Trans=> sends vesicles to plasma membrane
30
Pt with recurrent pyogenic infections, light colored skin, and neuropathy has defect in what process?
Chediak Higashi = mutation in lysosomal trafficking regulator gene required for Microtubule dependent sorting of proteins into vesicles
31
What drugs act on microtubules?
``` Mebendazole Griseofulvin Vincristine Paclitaxel Colchicine ```
32
What elements are required for microvilli, muscle contractions, "Cytokinesis", adherens junctions?
Actin and myosin
33
``` What structures composeL Desmin vementin Cytokeratin Lamins GFAP ```
Intermediate filaments
34
``` What is made by collagen: Type 1 Type 2 Type 3 Type 4 ```
T 1 = Bone, tendons, ligaments, scar, cornea, dentin T2= Cartilage, nucleus pulposus T3= Skin, BVs, Granulation tissue T4= basement membrane
35
Collagen production: Inside fibroblast RER Outside fibroblast
Inside RER= Gly-x-y synthesis, Hydroxylation, Glycosylation, Triple helix outside = Peptide cleavage, Cross links (Cu dep)
36
What part of collagen production requires Vitamin C and Cu?
Vit C= Hydroxylation | Cu = Cross linking hydroxylysine residue
37
Features of Alports syndrome?
Defect in T4 collagen X-linked Nephritis Deafness Ocular issues
38
What are features of Elastin?
Rich in proline and glycine NONhydroxylated Cross linking makes it Elastic Wrinkles= dec collagen & elastin Def in Marfans and Emphysema
39
Direct vs Indirect ELISA?
``` Indirect= Find Specific antibodies in pt serum using test antigen Direct= find Antigen in pt serum using antibody ```
40
What test is able to detect SNPs and genetic linkages?
Microarrays
41
Phenotypes vary among individuals with same genotype?
Variable expressivity
42
One gene contributes to multiple phenotypes?
Pleiotropy
43
Mutation at different sites produce similar phenotypes?
Locus heterogeneity = Albinism
44
Different mutation in the same site produce same phenotype?
Allelic heterogeneity = Beta thalasemia
45
Associations with ADPKD?
Ch 16 Berry aneurysms MVP
46
Pt with telangiectasia, epistaxis, skin discolorations, and CT scan shows SAH?
Osler-Weber- Rendu Blood vessel disorder= AVM leading to SAH
47
NT changes seen in Huntingtons?
Dec ACh + GABA
48
What is the defect in CF?
Defect in ATP-gated Cl channel 508 Phe deletion causing abnormal folding of CFTR leading to protein retained in RER **N-acetylcystein loosens mucus
49
Meiosis 1 vs 2 nondisjunction?
``` M1= Heterozygote M2= homozygote ```
50
``` Water soluble vitamins: B1= B2= B3 B5 B6 B7 B9 B12 Ascorbic acid ```
``` B1= Thiamine B2= Fiboflavin B3= Niacin B5= Pantothenic acid = CoA B6= pyridoxine B7= Biotin B9= Folate B12= Cobalamin Ascorbic acid= Vit C ```
51
What vitamin is needed for FA synthase?
B5 pantothenate= essential for CoA | **required for FA synthesis
52
``` What molecules carry: Carbon groups (CO2) 1-carbon units Methyl group Aldehyde ```
``` Biotin = CO2 THF= 1 carbon SAM= methyl Pyridoxin = Aldehyde ```
53
What is NADPH made by the Pentose phosphate shunt used?
Anabolic processes (Cholesterol, FA) Respiratory burst P450 Glutathione reductase
54
Hexokinase or glucokinase: Induced by Insulin Feedback inhibition by G6P Mutated in Maturity onset Diabetes of young
Glucokinase induced by insulin Hexokinase inhibited by G6P Glucokinase mutated in MODY
55
Pyruvate dehydrogenase complex requires what cofactors? What other enzyme has the same requirements?
``` Pyrophosphate (B1/ thiamine) FAD (B2 riboflavin) NAD (B3 niacin) CoA (B5 panthothenate) Lipoic acid **a-Ketogluterate dehydrogenase ```
56
Pt with arsenic poisoning will have vomiting, rice water stools, and garlic breath due to inhibition of what?
Lipoic acid=> stops Pyruvate dh and thus TCA
57
``` ETC inhibitors: C1 CoQ (C3) CC/ C4 C5/ ATP synthase ```
``` C1= Rotenone C3= Antimycin Cc/C4= CO/ cyanide C5= Oligomycin ```
58
What are some ETC uncoupling agents/ increase O2 consumption and produce heat with NO ATP synthesis?
2,4-DNP Aspirin Thermogenin in Brown fat
59
``` What are the steps of Gluconeogenesis in: Mitochondria Cytosol Cytosol ER ```
Mito: Pyr----biotin---> OAA OAA---GTP---> PEP F1,6-BP-----> F6P ER: G6P----> Gluc
60
Why can Odd chain FA be used for Glucose production but Even chains cannot?
Odd chains metabolized into Succinyl CoA which feeds into OAA and makes Glucose Even chains only make Acetyl CoA
61
@ what sites are HMP shunt working the highest?
``` Sites of Steroid of FA synthesis Mammary glands Adrenal cortex Liver RBC ```
62
What is seen on the blood smear of person with G6PD def?
Heinze bodies= oxidized Hb | Bite cells= removal of heinze bodies
63
Why are Aldolase B and Uridyl transferase Def more severe than Fructokinase and Galactokinase def?
They deplete Phosphate levels by accumulation the phosphorylated forms of the sugars causing less for ATP production
64
Essential AAs: Glucogenic Ketogenic
``` Glucogeic== Met, Val, His Ketogenic= Leu, Lys ```
65
Acidic vs Basic AAs?
``` acidic= Asp, Glu basic= His, Arg, Lys ```
66
What two AAs are required in excess during growth?
Arg + His
67
What is the consequence of Hyperammonemia?
Depletion of a-ketogluterate leading to Inhibition of TCA cycle
68
What are some of the treatments for hyperammonemia?
Limit proteins Phenylbuterate/ Benzoate= bind AAs Lactulose
69
What cofactor is required for Phenylalanine hydroxylase and Tyrosine hydroxylase?
BH4 (tetrahydropterion) * *Also required for Trp--> 5HT * *Arg==> NO
70
The production of what NTs requires BH4?
Dopamine + 5HT
71
DOPA carboxylase converts DOPA-> DA but requires what cofactor?
B6 pyridoxine
72
Dopamine--> NE requires what cofactor?
Vitamin C
73
What kind of reaction makes NE--> Epi?
Methylation thus requires SAM
74
Histamin production requires what cofactor?
B6 (carboxylated from histidine)
75
Porphyrin production is made by what AA and requires what cofactor?
(Glycine + B6) + Succinyl CoA=> HEME
76
What things are derived from Arg?
NO Creatine Urea
77
What are some treatment options for Homocystinuria?
Dec Methionine Inc Cysteine Inc B6 & B12 & Folate
78
Urine Cyanide-Nitroprusside test is diagnostic of what genetic disease?
Cystinuria
79
Pt with mental retardation and increased serum alpha ketoacids has what defect?
Maple syrup urine disease=> blocked degradation of Branched amino acids (Ile, Leu, Val)
80
Accumulation of Ceremide trihexoside leads to what?
``` Fabry's ==> a-galactosidase def CV + RENAL disease Angiokeratomas peripheral neuropathy *ONLY XR ```
81
Accumulation of Glucocerebroside leads to what?
Gauchers = Glucocerebrosidase def Bone necrosis Hepatosplenomegaly Wrinkled Kupffer cells
82
Accumulation of Sphingomyelin leads to what?
Neiman Picks = Sphingomeyelinase def Neurodegeneration Cherry red Macula spots HEPATOMEGALY
83
Accumulation of GM2 ganglioside leads to what?
Tay Sachs = Hexominidase def Neurodegeneration Cherry Red macula spots NO hepatosplenomegaly
84
Accumulation of Galactocerebroside leads to what?
Krabbe = Galactocerebrosidase def Neuropathy Optic atrophy Globoid cells
85
Accumulation of Cerebroside sulfate leads to what?
Metachromatic leukodystrophy = Arylsulfatase Ataxia Demyelination Dementia
86
Accumulation of LCFA leads to what?
Adrenoleukodystrophy
87
Accumulation of Heparan/ dermatan sulfate leads to what?
Hurlers = Iduronidase def *Gargoylism, Corneal clouding, Hepatosplenomegaly Hunters = Iduronate sulfatase def *Aggressive, NO corneal clouding
88
What are two metabolic defects in FA oxidation?
Carnitine def | Acyl-CoA dh def
89
Pt with weakness, hypotonia, Hypoketotic and hypoglycemic has what def?
Carnitine def
90
Pt with Hypoglycemia, Hypoketonemia, and increased Dicarboxylic acids has what def?
Acyl-CoA dh def
91
HMG-CoA is converted into what during Cholesterol synthesis?
Mevalonate by HMG-CoA reductase
92
Where is LPL located?
Endothelial cells
93
What is the action of Hormone sensitive lipase?
degradation of TG stores in adipose tissue
94
What apolipoprotein mediates Remnant uptake?
Apo E | **Only LDL does have them
95
What apolipoprotein activates LCAT?
apo A1 | *ONly HDL
96
What apolipoprotein is a cofactor/ activator of LPL?
apo CII --> HDL gives to VLDL/ chylomicrons
97
What is the difference btwn Apo B48 & B100?
B100 in VLDL can BIND LDL receptors

FA genetics/ Biochem (10 decks)

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