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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 are the function of vit C
Protective against malaria
ATP hyrdolysis couple to energetically unfavorable rxns
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Antioxidant - facilitates iron absorption by keeping iron in the Fe2+ reduced state - necessary for hydroxylation of proline and lysine collagen bridges - necessary for dopamine beta hydroxylase which converts DA to NE

2. What does primase do
Makes RNA primer on which DNA poly III can initiate replication
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Transmitted only through mother - all offspring of affected females may show signs of disease
Essential fructosuria - fructokinase AR

3. caf
Neurofibromatosis type 1 (von Recklinghausens disease)
Creat a nick in the helix to relieave supercoils created during replication
Proline and glycine (non glycosylated forms)
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

4. How does abetalipoproteinemia present and What is the defect
Early in life - AR - inability to synthesize lipoproteins due to def in apoB100 and B48 - intestinal biopsy shows accumulation within enterocytes due to inability to export absorbed lipid as chylomicrons - failure to thrive - steatorrhea - acanthocyt
Same as sprint + OXPHOS
Tyrosine
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

5. Giving folate during early pregnancy is important to prevent what birth defects
GAA
Neural tube
Proline and lysine - vit C
Fibroblast

6. What makes up a nucleotide

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7. What is mosaicism and give an example
Passed to glutamate - then to alanine enters blood - enters liver - coverted to pyruvate and transfers ammonium back to glutamate which gives it to the urea cycle
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
Ribose 5- P to PRPP
Consesus sequenec of base pairs

8. What step begins the urea cycle and What is the enzyme needed - Where does it happen
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Males are infertile due to bilateral absence of vas deferens
Asp and Glu
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects

9. What does apoE do
Dopamine beta hydroxylase
Mediates extra remnant take up
Paclitaxel
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis

10. What is a missense mutation
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Changed AA (convservative - new AA is similar in chemical structure)
Stop codon is recognized by release factor - and completed protein is released from ribosome
Zero

11. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
Reads usual codon but inserts wrong AA
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Vit K antagonist
Dermatitis - alopecia - enteritis

12. What are the functinos of vitamin A
Inc Cl - in sweat
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Inc insulin - dec cAMP - dec PKA
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles

13. What does vit B3 def result in
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Post to neg
Mucus secreting globlet cells and antibody secreting plasma cells
Inc melt - dec fluidity

14. central and peripheral demyelination with ataxia and dementia
Enhancers
NADH - NADPH - FADH2
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

15. What CETP do
F16BP
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
CGG
3' end (with CCA)

16. phosphorylation of glucose to yield glucose 6 phosphate serves as the 1st step of what rxns and what enzymes catalyze it
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Superoxide dismutase
Essential fructosuria - fructokinase AR

17. How are the many staggered tropocollagen molecules reinforced
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Thymic - parathyroid and cardiac
DNA
Leu - lys

18. What is the treatment for orotic aciduria
Inhibits 50S peptidyltransferase
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Oral uridine administration
PFK - rate limiting enzyme

19. In base excision repaire - what recognizes and removes damaged bases and what cuts the DNA to remove the empty sugar
HVA
Must be both activated and inactivated for cell cycle to progress
Specific glycosylases - AP endonuclease
Initiate chains

20. Which type of chromatin is less condensed - transcriptionally active - sterically accesible
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Alpha - ketoglutarate dehydrogenase complex
Euchromatin
Dermatitis - glossitis - and diarrhea

21. What is the wernicke - korsakoff clinical picture
Tropoelastin with fibrillin scafolding
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
Asp and Glu
VMA

22. What is heteroplasmy
Exons
Lysine and leucine
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease

23. What are the mRNA stop codons
Liver - also in kidney and gut epithelium
SnRNPs and other proteins
Silencers
UGA - UAA and UAG

24. What is NADPH's role inside RBCs
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
Inc permeability of membrane causing a dec in proton gradient and inc in O2 consumption - ATP synthesis stops - but electron transport continues to produce heat
Medial dorsal nucleus of thalamus - mamillary bodies
Keep glutathione reduced so it can detoxify free radicals and peroxides

25. What is Retin A used topically for
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Wrinkles and acne
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

26. What catacholamine step is SAM required for
Read from a fixed starting point as a continuous sequence of bases
Conversion of NE to epi
Same AA - often base change in 3rd position of codon (tRNA wobble)
Polyneuritis - symmetrical muscle wasting

27. What does degenerate/rundant genetic code refer to...
Arginine
More than 1 codon may code for the same amino acid
Facial flushing
AMP - fructose 2 -6 BP

28. How does insulin inhibit glycogenolysis
Wrinkles and acne
CGG
Ribos first then deoxyribos with ribonucleotide reductase
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it

29. What is the most abundant protein in the body
Collagen
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Inc vit B6

30. What is NADPH used for
Changed AA (convservative - new AA is similar in chemical structure)
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Anabolic processes as a supply of reducing equivalents
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

31. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
Griseofulvin
RER
Lactate
Von gierkes - glucose 6 phosphatase

32. How many rings do purines have
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
2 rings
Disease

33. What enzyme degrades a small amount of glycogen in lysosomes
Alpha 1 -4 glucosidase
Acetly- CoA - CO2 - NADH
HGPRT - defective purine salvage - excess uric acid production
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

34. spheroid RBCs due to spectrin or ankyrin defect - hemolytic anemia - inc MHCH - splenectomy is curative
BOne
Cri du chat
Hereditary spherocytosis
ATP

35. progressive neurodegeneration - developmental delay - cherry red spot on macula - lysosomes with onion skin - NO hepatosplenomegaly
NF2 on chromosome 22
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Connective tissue

36. What happens in vit K def
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
They yield only acetyl - CoA equivalents

37. What happens in vit D excess
Oligomycin
Microtubules
Protective against malaria
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage

38. What is the origin of replication
Schwann cells - lens - retina - kidneys
Diphyllobothrium latum
GTP
Particular sequence of DNA where replicatino begins - may be single of multiple

39. What creates the musty body odor in PKU
Disorder of aromatic amino acid metabolism
Oxidized hemoglobin precipiated within RBCs
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two

40. What is the defect in cystinuria
Exons
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

41. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
FAP
HMG- CoA (HMG- CoA to mevalonate
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step

42. What are the fetal screening measures for Down
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies

43. in a 100 meter sprint Where does energy come from
Stored ATP - creatine phosphate - anaerobic glycolysis
Ketone - methyl
Post to neg
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid

44. What are the symptoms of vit A def
40 - 60 - 80
5' to 3'
Night blindness - dry skin
2pq

45. What causes Edwards syndrome and What is it
Oxalacetate
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
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Fasting

46. What two cells are particularly rich in RER
Mucus secreting globlet cells and antibody secreting plasma cells
Oxidative is irreversible
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
DTMP

47. bilateral - massive enlargement of of kidneys due to multiple large cysts
ADPKD
Robertsonian translocation and mosaicism
Mcardle's - skeletal muscle glycogen posphorylase
Nine

48. How does chloramphenicol work
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Inhibits 50S peptidyltransferase

49. What activates the pyruvate dehydrogenase complex
Exercise: inc NAD/NADH - inc ADP - inc Ca
Palate - facial and cardiac defects
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Von gierkes - glucose 6 phosphatase

50. The pyruvate dehydrogenase complex serves In what reaction: products
Acetly- CoA - CO2 - NADH
Glycine - aspartate - glutamine
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact