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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 hardy weinber heterozygote prevalence
Peroxide
Thymic - parathyroid and cardiac
Unwinds DNA template at replcation fork
2pq

2. How many nucTIDEs is a tRNA and What does the secondary sturcture form
B100 and E
75 to 90 - cloverleaf
CGG
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele

3. What is the active form of vit D
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
1 -25 OH2 D3 = calcitriol
Each codon specifies only 1 amino acid
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis

4. What is the RDE of TCA cycle
Debranching enzyme
Isocitrate dehydrogenase
UDP glucose pyrophosphorylase
ATP and alanine

5. What are the two transgenic strategies in mice
SnRNPs
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer

6. What are the glucogenic/ketogenic amino acids
MRNA
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Initiate chains
Ile - phe - thr - trp

7. What are ketone bodies made from - where are they metabolized and how are they excreted
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Each codon specifies only 1 amino acid
Inhibits the Na/K pump by binding the K side
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

8. Type III collagen
Karyotyping
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Pyruvate to oxaloacetate (3C to 4C)
Phenylalanine hydroxylase

9. I g fat = ? Kcal
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Phenytoin - MTX - and sulfonamides
Nine

10. In what cells do the respiratory burst occur
Acetoacetate and beta hydroxybutyrate
Ribos first then deoxyribos with ribonucleotide reductase
PMNs
Active secretion in lungs and GI - reabsorbs in skin

11. What is the Name and function of vit B2
HDL
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Binds to LDL receptor - mediates VLDL secretion

12. In which structures do you find microtubules
ATP - citrate
Flagella - cilia - mitotic spindles
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

13. What can vit B3 be used to treat
CarTWOlage
Sulfation
Hyperlipidemia
Vit K antagonist

14. What step begins the urea cycle and What is the enzyme needed - Where does it happen
Met - val - arg his
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles

15. Why can't even chain fatty acids produce new glucose
1 ring
X linked frame shif mutation
They yield only acetyl - CoA equivalents
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light

16. What rxn does propionyl - CoA carboxylase catalyze
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

17. What residues are hydroxylated in step 2 of collagen synthesis - and What does this require
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Proline and lysine - vit C
FMR1 gene - methylation - associated with chromosomal breakage
Alcohol version of glucose - can trap glucose in cell - aldose reductase

18. What lab value can distinguish orotic aciduria from ornithine transcarbamoylase def?
OTC has hyperammonemia - orotic aciduira does not
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Inhibits RNA polymerase II - found in death cap mushrooms
Oxalacetate

19. Why is albinism inheritnace varialbe due to...
Locus heterogeneity - ocular albinism is x- linked recessive
DTMP
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
Mediates extra remnant take up

20. What do def in in enzymes of gluconeogenesis cause
Exons
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Hypoglycemia
Antioxidant - protects RBCs and membrances from free radical damage

21. What enzyme converts phenylalanine to tyrosin
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Rb and p53
Removes phosphate group from substrate
Phenylalanine hydroxylase

22. What is RNAi used for
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
DsRNA promotes degradation of target mRNA knocking down gene expression
B-100 - CII and E

23. what findings are associated with marfans
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Robertsonian translocation and mosaicism
MEN - 2A and 2B with ret gene
L form

24. How do labile celss grow and regenerate and What are examples
Silencers
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells

25. Type II collagen
Cartilage - hyaline - vitreous body - nucleus pulposus
VMA
Unmethylated - newly synthesized - HNPCC
Medial dorsal nucleus of thalamus - mamillary bodies

26. What is the function of Zinc
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Muscle
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver

27. What order kinetics does EtOH dehydrogenase have
Bruton's agammaglobulinemia - wiskott - aldrich - fabrys disease - G6PD def - ocular albinism - Lesch - Nyhan syndrome - Duchenne and Becker Muscular Dystrophy - hunter's syndrome - hemophilia A and B
Lysine and leucine
Abnormal protein folding - degradation before reaching cell surface
Zero

28. What does degenerate/rundant genetic code refer to...
B6
More than 1 codon may code for the same amino acid
Malapsorption syndromes like sprue or CF or mineral oil intake
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response

29. What do B- complex vitamin deficiencies often result in
Dermatitis - glossitis - and diarrhea
Specific glycosylases - AP endonuclease
OTC has hyperammonemia - orotic aciduira does not
L form

30. central and peripheral demyelination with ataxia and dementia
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Methionine encode by only 1 codon (AUG)
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

31. Do balanced translocations cause abnl phenotype
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
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
No
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

32. What is the RER called in neurons and What is made there
Nissl body - enzyme and NTs
25OHD3
Dec DNA - dec lymphos leads to SCID
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation

33. In what cell is collagen synthesis initiated
Removal of N or C termal propeptides from zymogens to generate mature proteins
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
III - joint dislocation - anuerysms - organ rupture
Fibroblast

34. What is the structure of elastin
Tropoelastin with fibrillin scafolding
Superoxide dismutase
Prevent strands from reannealing
Conversion of NE to epi

35. Type I collagen
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Autosomal recessive diseases
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Methionine encode by only 1 codon (AUG)

36. What CETP do
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Binds to LDL receptor - mediates VLDL secretion
Cofactor for LPL
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)

37. Type IV BM
Free ribosomes
4 under the floor
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
Same AA - often base change in 3rd position of codon (tRNA wobble)

38. What is the RDE of de novo pyrimidine synthesis
Coenzyme A - lipoamide
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
DNA
Carbomoyl phosphate synthetase II

39. What is the mutation in beckers muscular dystrophy - What is the severity and time of onset
Mutated dystrophin gene - less severe - adolescence
Fibroblast
Alpha 1 -4 glucosidase
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints

40. What apolipoprotein is on LDL
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Alkaptonuria - may have debiliating arthralgias
B100

41. What is sorbitol - how and why is it made
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Base + ribose

42. What enzymes metabolize fatty acids and amino acids
One
Acetoacetate and beta hydroxybutyrate
Protein
Ribos first then deoxyribos with ribonucleotide reductase

43. What does lactase deficiency cause
VMA
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Griseofulvin

44. How does warfarin work
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Vit K antagonist
Superoxide dismutase
Mucus secreting globlet cells and antibody secreting plasma cells

45. What metabolic rxns occur in the cytoplasm
Lysine and arginine
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Euchromatin
2 rings

46. What are the irreversible enzymes of gluconeogenesis
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
4 under the floor
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Degradation of TG stored in adipocytes

47. How is Lesch Neyhan inherited
Hereditary spherocytosis
X- linked recessive
Binds 50S - blocking translocation
Histidine

48. 1 g of protein or cabrohydrate = ?kcal
Huntingtons
Four
Epithelial cells
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive

49. How does abetalipoproteinemia present and What is the defect
Oxalacetate
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
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
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

50. How do tetracyclines work
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Bind 30s subunit preventing attachment of aminoacyl - tRNA