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Biochemistry

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Answer 50 questions in 15 minutes.
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1. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Removal of N or C termal propeptides from zymogens to generate mature proteins
Lariat shape in order and remove intron precisely and join 2 exons
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)

2. What are the glucogenic/ketogenic amino acids
Phosphofructokinase 1
Microarrays
BOne
Ile - phe - thr - trp

3. What do neurofilaments stain for
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Neurons
Read from a fixed starting point as a continuous sequence of bases
Miscarriage - stillbirth - chromosomal imbalance (down - patau)

4. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Alanine
ATP and alanine
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
VLDL

5. What are the symptoms of vit A excess
Failure to track objects or develop a social smile
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
1 -25 OH2 D3 = calcitriol

6. What does Ehlers Danlos cause and why
Avidin
Zero
Inc dicarboxylic acids - dec in glucose and ketones
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints

7. What is the breakdown product of dopamine
Ca/calmodulin in muscle to coordinate with muscle activity
Alanine
HVA
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted

8. Gene imprinting implies that How many alleles are active at a single locus
One
Night blindness - dry skin
Alpha 1 -6 and alpha 1 -4
Huntingtons

9. What is the function of Zinc
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Abnormal protein folding - degradation before reaching cell surface
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -

10. What does fomepizole do
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Pseudomonas and s aureus
Unwinds DNA template at replcation fork
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning

11. What is the breakdown product of epi
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Dermatitis - alopecia - enteritis
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Metanephrine

12. What are the names and sources of the two types of vit D found in nature
HMG- CoA synthase
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
ATP - citrate
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin

13. What happens in vit K def
Muscle
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Von Gierke's - Pompe - Cori - McArdle

14. What does vit B3 def result in
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

15. How doe NADH electrons from glycolysis and the TCA cycle enter the mitochondiria
Ca/calmodulin in muscle to coordinate with muscle activity
Inhibits 50S peptidyltransferase
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Nine

16. What apolipoproteins are on chylomicrons
SnRNPs and other proteins
APKD1 on chromosome 16
B48 - AIV - CII - E
Sucrose = glucose + fructose - lactose = glucose + galactose

17. What substance inside the cells replenishes NADPH
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
G6PD
Alpha and beta tubulin - dimers have two GTP bound
BOne

18. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
CFTR gene - 7 - Phe 508
DsRNA promotes degradation of target mRNA knocking down gene expression
Inc Cl - in sweat
NADPH

19. Which aspect of the spliceosome do patients with lupus make antibodies against
SnRNPs
ATP hyrdolysis couple to energetically unfavorable rxns
Purines= A - G pyrimidine = C - T (U)
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR

20. What are the mRNA stop codons
Asp and Glu
Removal of N or C termal propeptides from zymogens to generate mature proteins
Pyruvate - NAD+ - CoA
UGA - UAA and UAG

21. What other complex is similar to the pyruvate dehydrogenase complex in that it has the same co - factors and generates succinyl - CoA
Prokaryotic only - elongates leading strand by adding deoxnucTIDE to the 3' end. Elongates lagging strand until it reaches primer of preceeding fragment. 3' to 5' exonuclease activity 'proofreads' each added nucTIDE
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Conversion of NE to epi
Alpha - ketoglutarate dehydrogenase complex

22. What does lipoprotein lipase do
Terminal regions - tropocollagen
Elastase - inhibited by alpha1 antitrypsin
Degredation of TG circulating in chylomicrons and VLDLs
Flagella - cilia - mitotic spindles

23. What rxn creates ATP
Basement membrane or basal lamina
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase

24. What is the most abundant type of RNA
Glycogen synthase
After citruline
RRNA
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year

25. What are possilbe presentation for galactokinase def
Glucose - 2Pi - 2ADP - 2NAD+
Not all individuals with a mutant genotype show the mutant phenotype
Failure to track objects or develop a social smile
Cartilage - hyaline - vitreous body - nucleus pulposus

26. What is the order of severity for the different types of mutations
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Nonsense > missense > silent
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin

27. What are the irreversible enzymes of gluconeogenesis
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Familial hypercholesterolemia - hyperlipidemia type IIA
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

28. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
Proline and glycine (non glycosylated forms)
B6
FAP
ATP

29. What is the amino acid precursor for porphyrin and heme
Intermediate filaments
B100 and E
Glycine
25OHD3

30. What happens in termination of proteins synthesis
Stop codon is recognized by release factor - and completed protein is released from ribosome
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Neurofibromatosis type 1 (von Recklinghausens disease)
P2 +2pq+ = 1

31. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
Glycine - aspartate - glutamine
Schilling test
Rb and p53
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais

32. What is mosaicism and give an example
If pt inherits or develops a mutation in a tumor suppresor gene - the complementary allele must be deleted/mutated before cancer develops - not true of oncogenes - retinoblastoma
Activates LCAT
Occurs when cells in the body have different genetic makeup - can be germline mosaic - which may produce a disease that is not carried by parents somatic cells - lyonization - random X inactivation in females
4 under the floor

33. Outside the fibroblast What part of procollagen is cleaved and What is it transformed into
Night blindness - dry skin
Ketone - methyl
Inc glucagon - inc cAMP - inc PKA
Terminal regions - tropocollagen

34. What is the pathway in the fed state leading to dec FBPase -2 and inc PFK-2
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
CG- 3 > AT-2 - More CG content - melting point goes up
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
Inc insulin - dec cAMP - dec PKA

35. What is the RDE of glycogen synthesis
Glycogen synthase
III - joint dislocation - anuerysms - organ rupture
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
SnRNPs and other proteins

36. What is the activated carrier for electrons
NADH - NADPH - FADH2
Oxalacetate
Neuralgia
Ribos first then deoxyribos with ribonucleotide reductase

37. What is the complication of cystinuria
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Mediates extra remnant take up
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
4 under the floor

38. What does CATCH 22 stand for and What causes is...
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
In ER - glucose 6- P to glucose

39. What converts DOPA to dopamine
Dopa decarboxylase
Alpha - ketoglutarate dehydrogenase complex
Neg to pos
Antibiotic use or excessive ingestion of raw eggs

40. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
Alkaptonuria - may have debiliating arthralgias
Rotenone - CN- - antimycin A - CO
Fibrofatty replacement of muscle - cardiac myopathy
Nonsense > missense > silent

41. What are bite cells and when do you see them
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
ADPKD
Result from phagocytic removal of heinz bodies my macs - G6PD def
Glucose -6 phosphate

42. How does OTC def present
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
NADPH
Transmitted only through mother - all offspring of affected females may show signs of disease
Evident in first few days of life - can present last onest - excess carbamoyl phosphate converted to orotic acid - orotic acid in blood and urine - dec BUN and symptoms of hyerpammonemia

43. What is variable expression and What is an example
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Binds 50S - blocking translocation
Marasmus - muscle wasting
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver

44. What are covalent alterations
Alpha 1 -4 glucosidase
Phosphorylation - glycosylation - hydroxylation
Familial hypercholesterolemia - hyperlipidemia type IIA
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais

45. What is the hardy weinber heterozygote prevalence
Unmethylated - newly synthesized - HNPCC
2pq
RER
Ribose 5- P to PRPP

46. What happens on the nonoxidative arm of the HMP shunt and What is the key enzyme and cofactor
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Two
RNA
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1

47. What apolipoproteins are on IDL
Lacks glucose 6 phophatase
B100 and E
Basement membrane or basal lamina
Cri du chat

48. Describe the structure of cilia
Anabolic processes as a supply of reducing equivalents
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
9+2 arrangement of microtubules
Procollagen - triple helix of 3 alpha collagen chains

49. What two enzymes are involved in EtOH metabolism
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Ile - phe - thr - trp
EtOH dehydrogenase and acetaldehyde dehydrogenase

50. What are the water soluble vitamins - which ones are stored
Glutamate
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Specific glycosylases - AP endonuclease
Hepatic glycogenolysis - adipose tissue release of FFA - muslce and liver FFA - hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and proprionyl - coA (odd chain FFA)

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Biochemistry

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