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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 the rate limiting enzyme in cholesterol synthesis
P2 +2pq+ = 1
Mucus secreting globlet cells and antibody secreting plasma cells
HMG- CoA (HMG- CoA to mevalonate
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus

2. What 3 steps in RNA processing occur after transcription

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3. What fxn does glucokinase serve in the liver
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Thymic - parathyroid and cardiac
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP

4. Which RNA poly opens DNA at promotor site
RNA poly II
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Alcohol version of glucose - can trap glucose in cell - aldose reductase

5. trinucleotide repeat fo myotonic dystrophy
Asp and Glu
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
CTG

6. decreases In what substances can cause PKU
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
B48 - AIV - CII - E
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor

7. several distinct syndromes characterized by familial tumors of endocrine glands including pancreas - parathyroid - pituitary - thryoid and adrenal medulla - disorders and gene association
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
MEN - 2A and 2B with ret gene

8. What happens in vit D def
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
VMA
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive

9. Where is glucose 6 phosphatase found and What does it do
In ER - glucose 6- P to glucose
Vit K antagonist
Chylomicrons
Targets the proteins for lysosome

10. How do odd chain fatty acids participate in gluconeogenesis
Von Gierke's - Pompe - Cori - McArdle
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Intermediate filaments

11. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
CFTR gene - 7 - Phe 508
TRNA
Acetyl - CoA to malonyl - CoA (2C to 3C)
Tryptophan

12. What activates the pyruvate dehydrogenase complex
The triphosphate bond
Exercise: inc NAD/NADH - inc ADP - inc Ca
B6
Kidney - ears - eyes

13. Which cells are rich in smooth ER
Liver hepatocytes and steroid producing cells of the adrenal cortex
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
EtOH dehydrogenase and acetaldehyde dehydrogenase
G6PD

14. What does vit E def cause
CAG
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Intermediate filaments
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination

15. What two amino acids are required druing periods of growth and why
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Arg and his inc in histones Which bind negatively charged DNA
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Flagella - cilia - mitotic spindles

16. What are the two possible causes of albinism
75 to 90 - cloverleaf
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Oxidizes substrate
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

17. What does apoB100 do
Carbomoyl phosphate synthetase I
NADPH
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
Binds to LDL receptor - mediates VLDL secretion

18. bilateral acoustic schwannomas - juvenile cataracts
African Americans and Asians
NF2 on chromosome 22
Neurons
Two

19. What are the irreversible enzymes of gluconeogenesis
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Isocitrate dehydrogenase

20. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
Ca/calmodulin in muscle to coordinate with muscle activity
Fibrofatty replacement of muscle - cardiac myopathy
Neg to pos
Schwann cells - lens - retina - kidneys

21. What enzyme does fructose metabolism bypass to reach glycolysis
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
ATP - citrate
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
PFK - rate limiting enzyme

22. Where are cytosolic and organellar proteins made
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Free ribosomes
Makes RNA primer on which DNA poly III can initiate replication
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

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

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24. 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
Dec methionine - inc cystiene - inc B12/folate
NAD+
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first

25. What is the amino acid precursor for histamine
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Histidine
FISH
Lysine and arginine

26. What two rxns in in glycolysis require ATP
Mebendazole/thiabendazole
Promotor - TATA box - and CAAT box - AT rich
MRNA
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1

27. What is the Name and fxn of vit B12
Creat a nick in the helix to relieave supercoils created during replication
Transfers methyl units
Liver - also in kidney and gut epithelium
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase

28. What happens in elongation of protein synthesis

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29. What is variable expression and What is an example
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Anabolic processes as a supply of reducing equivalents
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Tropoelastin with fibrillin scafolding

30. Type IV collagen
Basement membrane or basal lamina
Inc NADH/NAD ratio in liver - causing diversion of pyruvate to lactate and OAA to malate - inhibiting gluconeogenesis and stimulating fatty acid synthesis. Leads to hypoglycemia and hepatic fatty liver change seen in chronic EtOH users
Glycine
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

31. Describe the location and fxn of the Na/K ATPase
Not all individuals with a mutant genotype show the mutant phenotype
Free ribosomes
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side

32. The pyruvate dehydorgenase complex serves In what reaction: reactants
Scrutinizes - hydrolyzes the bond
2 -4 DNP - aspirin
HVA
Pyruvate - NAD+ - CoA

33. What causes Edwards syndrome and What is it
Unmethylated - newly synthesized - HNPCC
EtOH dehydrogenase and acetaldehyde dehydrogenase
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
N to C

34. How is ammonium transported from muscle to the liver for urea cycle
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
Tuberous sclerosis
UDP glucose pyrophosphorylase
Polyneuritis - symmetrical muscle wasting

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

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36. What is the order of severity for the different types of mutations
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
Nonsense > missense > silent
B100
Dermatitis - alopecia - enteritis

37. What is the amino acid precursor for catecholamines
Phenylalanine
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Adds an inorganic phosphate onto substrate without using ATP

38. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
3' end (with CCA)
LDL
Dec DNA - dec lymphos leads to SCID
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

39. Where do you find elastin and What does it do
Acetly- CoA - CO2 - NADH
Changed AA (convservative - new AA is similar in chemical structure)
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.

40. What is trimming
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Removal of N or C termal propeptides from zymogens to generate mature proteins

41. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Degredation of TG circulating in chylomicrons and VLDLs
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

42. What converts tyrosine to DOPA
Tryosine hydroxylase
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Schilling test
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes

43. telangiectasia - recrrent epistaxis - skin discolorations - AVMs
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Glucose 6 phosphatase
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Schilling test

44. What is the TX for pyruvate dehydrogenase deficiency
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
FISH
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein

45. How do stable (quiescent) cells grow and regenerate and What are examples
Williams syndrome
Alpha - ketoglutarate dehydrogenase complex
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

46. What is uniparental disomy
SNP
Microarrays
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Read from a fixed starting point as a continuous sequence of bases

47. peripheral neuropathy - developmental delay - optic atrophy - glopoid cells
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Oxalacetate
Arg - lys - his - arg is most basic - has has no charge at body pH
Krabbes - galactocerebrosidase - galactocerebroside - AR

48. What does DNA poly I do?
Malapsorption syndromes like sprue or CF or mineral oil intake
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
5' of the incoming nucleotide

49. Which are the acidic amino acids
Essential fructosuria - fructokinase AR
ATP hyrdolysis couple to energetically unfavorable rxns
CGG
Asp and Glu

50. How do you diagnose CFTR
1 kind with multiple subunits
Inc Cl - in sweat
Malapsorption syndromes like sprue or CF or mineral oil intake
Night blindness - dry skin