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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 3 syndromes are associated with vit B1 def
Prevent strands from reannealing
Myeloperoxidase
In ER - glucose 6- P to glucose
Wernicke - korsakoff - dry and wet beriberi

2. Gene imprinting implies that How many alleles are active at a single locus
Exons
30 - 50 - 70
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
One

3. What is the amino acid precuros for niacin and serotonin/melatonin
Tryptophan
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Ribos first then deoxyribos with ribonucleotide reductase
Hypoglycemia

4. What is the function and name of vit B6
Covalent cross - linking by lysyl oxidase to make collagen fibrils
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
Protective against malaria
Sucrose = glucose + fructose - lactose = glucose + galactose

5. How does ethanol induce hypoglycemia
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Acetyl - CoA to malonyl - CoA (2C to 3C)
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
LDL

6. What does helicase do
Post to neg
APRT + PRPP
Pyruvate - NAD+ - CoA
Unwinds DNA template at replcation fork

7. What is incomplete penetrence and give an example
Not all individuals with a mutant genotype show the mutant phenotype
Cre - lox system
Basement membrane or basal lamina
NADPH

8. What substance in egg whites binds biotin
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Defect in fibrillin
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
Avidin

9. What is the order of severity for the different types of mutations
Nonsense > missense > silent
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
LCAT (lecithin cholesterol acyltransferase)
Colchicine

10. How many nucTIDEs is a tRNA and What does the secondary sturcture form
Nine
75 to 90 - cloverleaf
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
B-100 - CII and E

11. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
Fed
Schwann cells - lens - retina - kidneys
Familial hypercholesterolemia - hyperlipidemia type IIA
HDL

12. Give an example of a mitochondrial inherited disease
Thymic - parathyroid and cardiac
IMP precursor
Von hippel lindau - 3
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies

13. What is the defect in fructose intolerance and What does it cause
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Not all individuals with a mutant genotype show the mutant phenotype
Inc CPK and muscle biopsy
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

14. What converts tyrosine to DOPA
Phenylketones in urine
Tryosine hydroxylase
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

15. What is axonemal dynein
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Adds 2 carbon with the help of biotin
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Huntingtons

16. What does PURe As Gold and CUT The Py stand for
Purines= A - G pyrimidine = C - T (U)
FMR1 gene - methylation - associated with chromosomal breakage
Antioxidant - protects RBCs and membrances from free radical damage
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex

17. What does the TCA cycle produce per 1 acetyl CoA
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Fasting
Lariat shape in order and remove intron precisely and join 2 exons
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes

18. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Rb and p53
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage

19. What are the characteristics of prader willi syndrome How does it occur
VLDL
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
B12 and folate
Fed

20. Mediates reverse cholesterol transport from periphery to liver - acts as respository for apoC an apoE - secreted from both liver and small intestine
Eu - methionine - pro - formyl - methionine
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
HDL
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side

21. fibrillin defect leading to connective tissue disorder affecting skeleton - heart - and eyes
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Marfans
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Inc vit B6

22. What leads to the deletion of the dystrophin gene in duchenne's muscular dystrophy
Biotin
X linked frame shif mutation
Cytosol
Acetoacetate and beta hydroxybutyrate

23. Type II cartilage
Biotin
Same AA - often base change in 3rd position of codon (tRNA wobble)
Epithelial cells
CarTWOlage

24. Which aspect of the spliceosome do patients with lupus make antibodies against
SnRNPs
Sons of heterozygous mothers have 1/2 half chance of being affected - no male to male transmission - and often more severe in males - heterozygous females may be affected
Alpha and beta tubulin - dimers have two GTP bound
Phenylalanine hydroxylase

25. What happens in vit D excess
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Tryptophan
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
APRT + PRPP

26. What is the result of vit B5 def
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Epithelial cells
Avidin

27. How does patients present with ADPKD
Malabsorption and steatorrhea (ADEK)
Flank pain - hematuria - HTN - progressive renal failure
Grows slowly - collapses quickly
Cri du chat

28. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
Sons of heterozygous mothers have 1/2 half chance of being affected - no male to male transmission - and often more severe in males - heterozygous females may be affected
CFTR gene - 7 - Phe 508
Dopa decarboxylase
Marfans

29. energy malnutrition resulting in tissues and muscle wasting - loss of subQ fat - variable edema
Locus heterogeneity - ocular albinism is x- linked recessive
Paclitaxel
ATP
Marasmus - muscle wasting

30. What does the golgi apparatus do on asparagine
DNA
De novo pyrimidine synthesis and urea - ornithine transcarbamoyl def in the urea cycle leads to a build of CP - then converted to orotic acid in pyrimidine synthesis pathway
75 to 90 - cloverleaf
Modifies N- oligosaccharides

31. What ribosomes do eukaryotes have
Exons
40 - 60 - 80
Oxidized hemoglobin precipiated within RBCs
Anabolic processes as a supply of reducing equivalents

32. What does Alports syndrome cause and why
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Exons
5' to 3'
Glycine

33. What is NADPH's role inside RBCs
Histidine
Keep glutathione reduced so it can detoxify free radicals and peroxides
Protein kinase A
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins

34. depression - progressive dementia - choreiform movements - caudate atrophy and dec levels of GABA and ACH in the brain
Huntingtons
Met - val - arg his
Malonyl coa
Tuberous sclerosis

35. What is the RER called in neurons and What is made there
Marasmus - muscle wasting
Neither of 2 alleles is dominant - blood groups
Nissl body - enzyme and NTs
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration

36. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Cre - lox system
Alanine
Core proteins
Chronic granulomatous disease - no respiatory burst - no formatino of ROS

37. What are the symptoms of vit A def
Night blindness - dry skin
Glycogen phosphorylase
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Inhibit DNA gyrase specific for prokaryotic topoisomerase

38. Outside the fibroblast What part of procollagen is cleaved and What is it transformed into
Makes RNA primer on which DNA poly III can initiate replication
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Mebendazole/thiabendazole
Terminal regions - tropocollagen

39. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
Inc insulin - dec cAMP - dec PKA
Oxalacetate
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus

40. recurrent pulmonary infxns in CF are due to what organisms
Pseudomonas and s aureus
Makes RNA primer on which DNA poly III can initiate replication
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
HGPRT - defective purine salvage - excess uric acid production

41. 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
Two
Alpha 1 -6 and alpha 1 -4
Neuralgia

42. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Colchicine
Intermediate filaments
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
SnRNPs and other proteins

43. Where is acetaldehyde located
32 - malate aspartate shuttle
Disorder of aromatic amino acid metabolism
Mitochondria
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

44. How many rings do purines have
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Attachment of ubiquitin to defective proteins tag them for breakdown
2 rings
Glycogen and FFA oxidation; glucose conserved for final sprinting

45. What tissue samples are used for karyotyping
Blood - bone marrown - amniotic fluid - placental tissue
RRNA
Breaks down acyl - coa to acetyl coa groups in mito
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle

46. Acetyl - CoA carboxylase catalyzes what rxn
Asp and Glu
Acetyl - CoA to malonyl - CoA (2C to 3C)
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)

47. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Connective tissue
SnRNPs
Glucose 6 phosphatase

48. Where is hexokinase found - What is its Km and Vmax and what uninduces it
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Paclitaxel
Inc insulin - dec cAMP - dec PKA
Consesus sequenec of base pairs

49. What causes Marfan syndrome
Change resulting in early stop codon
Defect in fibrillin
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
5' to 3'

50. What enzyme turns ROS to H2O2
Superoxide dismutase
Carnitine shuttle - acyl - coa from cyto to mito
Alanine
Basement membrane or basal lamina