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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. What does a decrease in decrease in NADPH lead to and why
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Histidine
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

2. What does the golgi apparatus do on asparagine
Superoxide dismutase
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Modifies N- oligosaccharides
SAM

3. What substances are uncouling agents
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
2 -4 DNP - aspirin
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

4. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Orotate precursor - with PRPP added later
Promotor - TATA box - and CAAT box - AT rich
Stop codon is recognized by release factor - and completed protein is released from ribosome
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

5. What collagen type is most frequently affected in ehlers danlos and What are common complications
Von Gierke's - Pompe - Cori - McArdle
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
III - joint dislocation - anuerysms - organ rupture
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome

6. What do DNA topoisomerases do
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Terminal regions - tropocollagen
Alpha 1 -6 and alpha 1 -4
Creat a nick in the helix to relieave supercoils created during replication

7. What is the results of vit B1 def
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Glutamate

8. congenital microdeletion of long arm of chromosoe 7 with findings of elfin facies - mental retardation - hypercalcemia - well developed verbal skills - extreme friendliness with strangers - cardiovascular problems
Williams syndrome
CGG
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

9. What does hormone sensitive lipase do
Degradation of TG stored in adipocytes
B48 - AIV - CII - E
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Hypoglycemia

10. Infection with what organism can cause B12 def
After citruline
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
TTP
Diphyllobothrium latum

11. What is the source of energy in the fasting state between meals
Dopa decarboxylase
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
Cofactor for LPL
Glycogen and FFA oxidation; glucose conserved for final sprinting

12. What are the names and sources of the two types of vit D found in nature
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
MRNA
Phosphorylation - glycosylation - hydroxylation

13. How many ATP are created by aerobic metabolism of glucose in the heart and liver via what shuttle
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
32 - malate aspartate shuttle
Dermatitis - glossitis - and diarrhea

14. Which cells are rich in smooth ER
Liver hepatocytes and steroid producing cells of the adrenal cortex
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Debranching enzyme
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it

15. hepatosplenomegaly - aseptic necrosis of femur - bone crisis - MACS that look like crumpled tissue paper

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16. How many rings do pyrimidines have
1 ring
IDL
Lactate
Lysine and arginine

17. What causes maple syrup urine disease and What does it lead to...
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Phenylketones in urine
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
Dec in alpha ketoacid dehydrogenas leading to blocked degredation of branches amino acids like Ile - Leu - and Val - severe CNS defects mental retardation and death

18. A small proportion of Down syndrome is due to What two genetic events
SnRNPs
2pq
Robertsonian translocation and mosaicism
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood

19. What is the most common urea cycle disorder and What is the mode of inheritance?
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Stored ATP - creatine phosphate - anaerobic glycolysis
NADH - NADPH - FADH2

20. What does amino acid catabolsim results in the formation of what?
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
HMG- CoA synthase

21. What are the purely ketogenic amino acids
Free ribosomes
Leu - lys
Vit K antagonist
ATP

22. How do stable (quiescent) cells grow and regenerate and What are examples
Males are infertile due to bilateral absence of vas deferens
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Two
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.

23. What is sorbitol - how and why is it made
Exons
Four
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase

24. What is axonemal dynein
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Carbomoyl phosphate synthetase II
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

25. What test is used for B12 def
Schilling test
Von gierkes - glucose 6 phosphatase
Alpha - ketoglutarate dehydrogenase complex
MRNA

26. What 3 steps in RNA processing occur after transcription

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27. What is the most abundant protein in the body
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Collagen
Dec methionine - inc cystiene - inc B12/folate
Same AA - often base change in 3rd position of codon (tRNA wobble)

28. What is the RDE of the HMP shunt
Alpha 1 -4 glucosidase
Specific glycosylases - AP endonuclease
Glucose 6 phosphate dehydrogenase (G6PD)
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)

29. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Collagen
Krabbes - galactocerebrosidase - galactocerebroside - AR
HGPRT - defective purine salvage - excess uric acid production
Result from phagocytic removal of heinz bodies my macs - G6PD def

30. cytoskeletal elements associated with cilia - flagella - mitotic spindle - neurones and centrioles
Microtubules
Paclitaxel
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Same as sprint + OXPHOS

31. What happens with dry beriberi
Polyneuritis - symmetrical muscle wasting
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding

32. What tissues have only aldose reductase
Schwann cells - lens - retina - kidneys
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Neg to pos
Wobble

33. What is the fxn of vit D
Ketone - methyl
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
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

34. Which enzyme involved in RNA synthesis does not require a template
Poly A polymerase - signal is AAUAA
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding
Change resulting in early stop codon
HMG- CoA synthase

35. How is ATP used by the cell
Adenosine to inosine
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
ATP hyrdolysis couple to energetically unfavorable rxns
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase

36. What 3 amino acids are necessary for purine synthesis
HMG- CoA reductase
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Scrutinizes - hydrolyzes the bond
Glycine - aspartate - glutamine

37. How do glucagon/epi lead to glycogenolysis
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
NF2 on chromosome 22
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)

38. What does a northern blot use as its sample
Inc melt - dec fluidity
O- oligosaccharaides
RNA
Degradation of TG remaining in IDL

39. In addition to fructose and galactose - what sugards should be excluded from the diets of patients with disorders of fructose or galactose metabolism
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Sucrose = glucose + fructose - lactose = glucose + galactose
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Neurofibromatosis type 1 (von Recklinghausens disease)

40. What does hartnups disease cause
Free ribosomes
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Actin and myosin
Orotate precursor - with PRPP added later

41. What catacholamine step is SAM required for
Conversion of NE to epi
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Inc insulin - dec cAMP - dec PKA

42. How do permanent cells grow and regenerate and What are examples of permanent cells
No
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Tropoelastin with fibrillin scafolding
Activates LCAT

43. What is the TX for PKU
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
LCAT (lecithin cholesterol acyltransferase)
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
II - VII - IX - X (1972) protein C and S

44. What does lipoprotein lipase do
Degredation of TG circulating in chylomicrons and VLDLs
GAA
AMP - fructose 2 -6 BP
Breaks down acyl - coa to acetyl coa groups in mito

45. Give an example of a mitochondrial inherited disease
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Cytosol - F 1 -6 BP to fructose 6 Phosphate

46. Which end of the tRNA is the amino acid bound to...

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47. What are bite cells and when do you see them
Result from phagocytic removal of heinz bodies my macs - G6PD def
P+q = 1
Degradation of TG stored in adipocytes
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response

48. What is a silent mutation
Brittle bone disease - most commonly lead AD with abnl type I collagen causing multiple fractures with minimal trauma - blue sclerae due to translucency of connective tissue over the choroid - hearing loss - dental imperfections due to lack of dentin
Peroxide
Degredation of dietary TG in small intestine
Same AA - often base change in 3rd position of codon (tRNA wobble)

49. What are the priorities for the body in fasting and starvation
DNA
HDL
Supply sufficient glucose to brain and RBCs and to preserve protein
Core proteins

50. What does Citrate Is Krebs starting substrate for making oxaloacetate
Von Gierke's - Pompe - Cori - McArdle
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
5' of the incoming nucleotide
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP