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Biochemistry

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Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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1. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
Lacks glucose 6 phophatase
Von hippel lindau - 3
Purines= A - G pyrimidine = C - T (U)
Exons

2. What is the function and name of vit B6
NAD+
Disease
Oxalacetate
Pyroxidine - converted to pyroxidine phosphate a cofactor used in transamination - decarboxylation - glycogen phosphorylase - cystathionine synthesis and heme synthesis - required for synthesis of niacin and tryptophan

3. What does DNA poly III do?
B100
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
Modifies N- oligosaccharides
Type II

4. central and peripheral demyelination with ataxia and dementia
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Ketone - methyl
CFTR gene - 7 - Phe 508
Vit K antagonist

5. What does a mischarge tRNA do
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Particular sequence of DNA where replicatino begins - may be single of multiple
Reads usual codon but inserts wrong AA
Procollagen - triple helix of 3 alpha collagen chains

6. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
IMP precursor
Fibrofatty replacement of muscle - cardiac myopathy
Phenytoin - MTX - and sulfonamides
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)

7. A small proportion of Down syndrome is due to What two genetic events
No
Robertsonian translocation and mosaicism
Must be both activated and inactivated for cell cycle to progress
Neurons

8. What is the structure of elastin
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Tropoelastin with fibrillin scafolding
Site of steroid synthesis and detoxification of drugs and poisons
Glycogenolysis to form glucose

9. What is the initial transcript called and What is the capped and tailed transcript called
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Lacks glucose 6 phophatase
APC on chromosome 5
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein

10. What is the pathway in the fed state leading to dec FBPase -2 and inc PFK-2
DTMP
Inc insulin - dec cAMP - dec PKA
Glycogenolysis to form glucose
Accelearted muscle breakdown

11. Which step in the de novo purine and pyrimidine synthesis pathway requires aspartate - glycine - glutamine and THF
Ribose 5- P to PRPP
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
OTC has hyperammonemia - orotic aciduira does not

12. cell signaling defect of fibroblast growth factor (FGF) receptor 3 - results in dwarfism - short limbs - head/trunk nl size - associated with advanced paternal age
Connective tissue
Achondroplasia
3' end (with CCA)
No

13. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
RRNA
DsRNA promotes degradation of target mRNA knocking down gene expression

14. How are the many staggered tropocollagen molecules reinforced
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
They yield only acetyl - CoA equivalents
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Von Gierke's - Pompe - Cori - McArdle

15. What is the RDE of fatty acid synthesis
Inc melt - dec fluidity
Sulfation
MRNA - tRNA
Acetyl - CoA carboxylase (ACC)

16. What converts dopamine to NE
Cre - lox system
Dopamine beta hydroxylase
Zero
Asp and Glu

17. What defects characterize DiGeorge syndrome
Hypoglycemia
Thymic - parathyroid and cardiac
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Conversion of NE to epi

18. Which direction does dynein go
TTP
Post to neg
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

19. What is the active form of vit D
Anchor muscle fibers - primarily in skeletal and cardiac muscle
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
Arginine
1 -25 OH2 D3 = calcitriol

20. facial lesions - hypopigmented 'ash leaf spots -' cortical and retinal hamartomas - seizures - mental retardation - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas - inc risk of astrocytomas
APC on chromosome 5
Tuberous sclerosis
Heterochromatin = HighlyCondensed
Only processed RNA

21. What makes up a nucleotide
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Base + ribose + phosphate (3' -5') phosphodiester bond
Deamination
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin

22. What is regeneration of methionine depedent on...
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
Adds 2 carbon with the help of biotin
X- linked recessive
B12 and folate

23. Which type of chromatin is condensed - transcriptionally inactive - sterically inaccessible?
Heterochromatin = HighlyCondensed
VLDL
CFTR gene - 7 - Phe 508
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol

24. What part of the pre mRNA contains the actual genetic information coding for protein
X linked frame shif mutation
Sulfation
Exons
Facial flushing

25. What does acetyl - CoA become before becoming palmitate
Carbomoyl phosphate synthetase II
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Inhibit DNA gyrase specific for prokaryotic topoisomerase
RNA poly II

26. What is variable expression and What is an example
40 - 60 - 80
Infection - free radicals generated by inflammatory response
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

27. What is NADPH's role inside RBCs
Keep glutathione reduced so it can detoxify free radicals and peroxides
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Liver and leafy veggies
Foliage - small reserve in liver - eat green leaves

28. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Alanine
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
MRNA - tRNA

29. What causes B12 def
Krabbes - galactocerebrosidase - galactocerebroside - AR
Dermatitis - alopecia - enteritis
Base + ribose
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns

30. What are the names and sources of the two types of vit D found in nature
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

31. Why enzyme breaks down elastin and what enzyme inhibits it
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Phenytoin - MTX - and sulfonamides
Elastase - inhibited by alpha1 antitrypsin
Thymic - parathyroid and cardiac

32. What happens in vit D excess
THFs
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Methionine encode by only 1 codon (AUG)
30 - 50 - 70

33. What collagen type is most frequently affected in ehlers danlos and What are common complications
Four
AMP - fructose 2 -6 BP
Dermatitis - enteritis - alopecia - adrenal insuff
III - joint dislocation - anuerysms - organ rupture

34. What does vit E def cause
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Transfers methyl units
AR

35. What are the glucogenic essential amino acids
Met - val - arg his
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Huntingtons
NF2 on chromosome 22

36. Type IV collagen
F16BP
Basement membrane or basal lamina
Paclitaxel
Methionine encode by only 1 codon (AUG)

37. Describe the pathophys of the aorta in a pt with marfans - and the eyes
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
CarTWOlage
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

38. Which step in the de novo purine and pyrimidine synthesis pathway requires just aspartate
Orotic acid to UMP
B100
Elastase - inhibited by alpha1 antitrypsin
VMA

39. What are the findings in orotic aciduria
NADH - NADPH - FADH2
Lysine and leucine
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
X- linked recessive

40. What enzyme converts phenylalanine to tyrosin
Phenylalanine hydroxylase
One
Four
Anabolic processes as a supply of reducing equivalents

41. FAP is due to deletion On what gene On what chromosome
Binds to LDL receptor - mediates VLDL secretion
CGG
APC on chromosome 5
3' end (with CCA)

42. Do balanced translocations cause abnl phenotype
Niacin - constituent of NAD and NADP - derived from tryptophan
Blood - bone marrown - amniotic fluid - placental tissue
No
Wernicke - korsakoff - dry and wet beriberi

43. What are the irreversible enzymes of gluconeogenesis
Dec methionine - inc cystiene - inc B12/folate
Cofactor for LPL
By inhibiting formation of the initiation complex and cause misreading of mRNA
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

44. What is the most abundant protein in the body
The triphosphate bond
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Collagen
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

45. What does cytokeratin stain for
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
ATP
Poly A polymerase - signal is AAUAA
Epithelial cells

46. What is the results of vit B1 def
Von hippel lindau - 3
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first

47. cardiomegaly - systemic findings leading to early death - dz and enzyme
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
IDL
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
VLDL

48. What is the function of Zinc
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Glucose 6 phosphatase
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Grows slowly - collapses quickly

49. What is the composition of urea and where do each part derive from
Failure to track objects or develop a social smile
Phenylethamolamine N methyl transferase
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
VLDL

50. What apolipoproteins are on chylomicrons
B48 - AIV - CII - E
Marasmus - muscle wasting
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Degradation of TG remaining in IDL

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Biochemistry

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