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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 is regeneration of methionine depedent on...
B12 and folate
MRNA - tRNA
32 - malate aspartate shuttle
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR

2. What happens in the first stage of collagen synthesis - and Where does it happen
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
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
UGA - UAA and UAG
Inc CPK and muscle biopsy

3. Where do you find elastin and What does it do
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.

4. developmental delay - gargoylism - airway obstruction - corneal clouding - hepatosplenomegaly
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Degradation of TG stored in adipocytes
Inhibits 50S peptidyltransferase

5. What does helicase do
Unwinds DNA template at replcation fork
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

6. How does ouabain work
Disorder of aromatic amino acid metabolism
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
Active secretion in lungs and GI - reabsorbs in skin
Inhibits the Na/K pump by binding the K side

7. Severe fasting hypoglycemia - inc glycogen storage in liver - inc blood lactate - hepatomegaly - dz and def enzyme
Von gierkes - glucose 6 phosphatase
Polycystic liver disease - berry aneurysm - mitral valve prolapse
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
Blood - bone marrown - amniotic fluid - placental tissue

8. Where is fructose 1 -6 bisphosphatase found and What does it do
Lysine and arginine
Same AA - often base change in 3rd position of codon (tRNA wobble)
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Neimann - pick - sphingomyelinase - sphingomyelin - AR

9. 90% of ADPKD cases are due to a mutation In what gene
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Vit K antagonist
APKD1 on chromosome 16
Neurons

10. What produces NADPH
CTG
HMP shunt
Unmethylated - newly synthesized - HNPCC
Marasmus - muscle wasting

11. Where is glucose 6 phosphatase found and What does it do
In ER - glucose 6- P to glucose
Phenylketones in urine
Arg and his inc in histones Which bind negatively charged DNA
II - VII - IX - X (1972) protein C and S

12. What form of amino acids are found in proteins
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Removes phosphate group from substrate
L form
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele

13. ADPKD is associated with What additional conditions
Polycystic liver disease - berry aneurysm - mitral valve prolapse
VMA
Leu - lys
Phosphofructokinase 1

14. What is loss of heterozygosity 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
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
G6PD
Read from a fixed starting point as a continuous sequence of bases

15. Gene imprinting implies that How many alleles are active at a single locus
One
They yield only acetyl - CoA equivalents
Zero
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR

16. What is variable expression and What is an example
Nature and severity of phenotype vary from 1 individual to another - NF type 1
HGPRT - defective purine salvage - excess uric acid production
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Alcohol version of glucose - can trap glucose in cell - aldose reductase

17. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Glutamate
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
RER

18. What substances inhibit phosphofructokinase -1
Proline and glycine (non glycosylated forms)
9+2 arrangement of microtubules
ATP - citrate
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning

19. What does vit E def cause
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible

20. What fxn does glucokinase serve in the liver
Carnitine shuttle - acyl - coa from cyto to mito
Nonsense > missense > silent
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
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

21. Acetyl - CoA carboxylase catalyzes what rxn
Acetyl - CoA to malonyl - CoA (2C to 3C)
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Colchicine

22. What occurs to oxaloacetate in starvation and DKA
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Citrate - acetyl coa from mito to cyto
Not all individuals with a mutant genotype show the mutant phenotype

23. What is a missense mutation
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
One
No - its non homologous
Changed AA (convservative - new AA is similar in chemical structure)

24. What makes up a nucleotide

25. What does apoB48 do
Mediates chylomicron secretion
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Degredation of dietary TG in small intestine

26. What is the activated carrier for aldehyddes
TTP
Accelearted muscle breakdown
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Thymic - parathyroid and cardiac

27. benign asymptomatic condition with elevated levels of fructose in urine and blood - dz and enzyme
ATP and alanine
Neimann - pick - sphingomyelinase - sphingomyelin - AR
Citrate - acetyl coa from mito to cyto
Essential fructosuria - fructokinase AR

28. What creates the musty body odor in PKU
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
B100 and E
Disorder of aromatic amino acid metabolism
Change resulting in early stop codon

29. What is the function and name of vit B6
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
Base + ribose + phosphate (3' -5') phosphodiester bond
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
APKD1 on chromosome 16

30. What is RNAi used for
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
DsRNA promotes degradation of target mRNA knocking down gene expression
Oxidative is irreversible
BOne

31. What is the activated carrier for electrons
Malapsorption syndromes like sprue or CF or mineral oil intake
Bind 30s subunit preventing attachment of aminoacyl - tRNA
NADH - NADPH - FADH2
Degredation of dietary TG in small intestine

32. How do stable (quiescent) cells grow and regenerate and What are examples
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Ca/calmodulin in muscle to coordinate with muscle activity
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels

33. A small proportion of Down syndrome is due to What two genetic events
Robertsonian translocation and mosaicism
Read from a fixed starting point as a continuous sequence of bases
Alpha 1 -6 and alpha 1 -4
UDP glucose pyrophosphorylase

34. What is disulfiram used for
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Procollagen - triple helix of 3 alpha collagen chains

35. What are bite cells and when do you see them
Result from phagocytic removal of heinz bodies my macs - G6PD def
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
CTG
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

36. What converts DOPA to dopamine
Dopa decarboxylase
Wernicke - korsakoff - dry and wet beriberi
30 - 50 - 70
VLDL

37. What is the defect in fructose intolerance and What does it cause
Dopamine beta hydroxylase
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Targets the proteins for lysosome
Carnitine shuttle - acyl - coa from cyto to mito

38. How does OTC def present
Seals.
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
Alpha 1 -6 and alpha 1 -4
Dermatitis - glossitis - and diarrhea

39. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
CFTR gene - 7 - Phe 508
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
ATP and methionine
30 - 50 - 70

40. What is the defect in I- hyperchylomicronemia
B6
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
HMP shunt
Removes phosphate group from substrate

41. What happens in termination of proteins synthesis
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Stop codon is recognized by release factor - and completed protein is released from ribosome
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
NADH - NADPH - FADH2

42. What is the RER called in neurons and What is made there
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Nissl body - enzyme and NTs

43. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
GTP
FAP
Unmethylated - newly synthesized - HNPCC
CarTWOlage

44. energy malnutrition resulting in tissues and muscle wasting - loss of subQ fat - variable edema
1 -25 OH2 D3 = calcitriol
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
Marasmus - muscle wasting
VMA

45. what happens in acyl coa dehyrdogenase def
Glucose 6 phosphatase
Intermediate filaments
Inc dicarboxylic acids - dec in glucose and ketones
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

46. What does vit B3 def result in
Mcardle's - skeletal muscle glycogen posphorylase
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Tropoelastin with fibrillin scafolding
Scrutinizes - hydrolyzes the bond

47. What 3 syndromes are associated with vit B1 def
Adipse tissue stores - keton bodies become the main source of energy fo the brain and heart - after these are depleted - vital protein degradation accelerates - leading to organ failure and death
B48 - AIV - CII - E
Wernicke - korsakoff - dry and wet beriberi
P2 +2pq+ = 1

48. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Defect in fibrillin
ATP and methionine
Liver - also in kidney and gut epithelium

49. Which kind of osteogenesis imperfecta is fata in utero or in neonatal period
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Sulfation
EtOH dehydrogenase and acetaldehyde dehydrogenase
Type II

50. What is mosaicism and give an example
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Hypoxanthine to xanthing and xanthine to uric acid
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
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