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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 RDE of fatty acid oxidation
II - VII - IX - X (1972) protein C and S
Carnitine acyltransferase I
HDL
Removes phosphate group from substrate

2. What is the treatment for dec affinity of cystathionine synthase for pyroxidal phosphate
Lactate
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Inc vit B6
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

3. What co - factors are required for the pyruvated dehydrogenase complex
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
CFTR gene - 7 - Phe 508
Niacin - constituent of NAD and NADP - derived from tryptophan
Glucose - 2Pi - 2ADP - 2NAD+

4. What is codominance and give an example
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
PMNs
Neither of 2 alleles is dominant - blood groups

5. What is the Name and fxn of vit B12
Acetyl - CoA carboxylase (ACC)
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Disorder of aromatic amino acid metabolism

6. What is the trinucleotide repeat in fragile X
Liver and leafy veggies
CGG
CFTR gene - 7 - Phe 508
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

7. How does warfarin work
No
Vit K antagonist
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase

8. What apolipoproteins are on chylomicrons
Mcardle's - skeletal muscle glycogen posphorylase
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
B48 - AIV - CII - E
2 -4 DNP - aspirin

9. What happens with wet beriberi
Dermatitis - enteritis - alopecia - adrenal insuff
Leu - lys
Night blindness - dry skin
High output cardiac failure - dilated cardiomyopathy - edema

10. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Dec DNA - dec lymphos leads to SCID
Cytosol
CFTR gene - 7 - Phe 508

11. How is ATP used by the cell
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
ATP hyrdolysis couple to energetically unfavorable rxns
Marfans
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage

12. What trinucleotide repeat in Huntingtons and what chromosome is it found on...
GAA
CAG - 4
Paclitaxel
Marasmus - muscle wasting

13. What is the defect in cystinuria
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Euchromatin
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
17 - 17 letters in von Recklinghausen

14. What is the RDE of ketogenesis
Carbomoyl phosphate synthetase I
Liver and leafy veggies
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
HMG- CoA synthase

15. What liberates glucose from glucose 6 P
Silencers
Glucose 6 phosphatase
Y shaped region along the DNA template where leading nad lagging strands are synthesized
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity

16. Which carbon bears the triphosphate and the energy source for bond formation

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17. What are the symptoms of vit A excess
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
IMP precursor
Bind 30s subunit preventing attachment of aminoacyl - tRNA

18. What are the fetal screening measures for Down
Enhancers
Four
Particular sequence of DNA where replicatino begins - may be single of multiple
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US

19. Formed and degradation of VLDL - delivers TGs and cholesterol to liver where they are degraded to LDL
PMNs
IDL
Alpha1 antitrypsin
Pyruvate - NAD+ - CoA

20. What happens in hyperammonemia
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Schwann cells - lens - retina - kidneys
Alkaptonuria - may have debiliating arthralgias

21. What is the most common urea cycle disorder and What is the mode of inheritance?
Initiate chains
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Activates LCAT

22. What is a silent mutation
O- oligosaccharaides
Same AA - often base change in 3rd position of codon (tRNA wobble)
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
P+q = 1

23. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Superoxide dismutase
Eu - methionine - pro - formyl - methionine
Orotic acid to UMP

24. In eukaryotes - What does RNA poly II make
Heterochromatin = HighlyCondensed
MRNA
Anabolic processes as a supply of reducing equivalents
Inc glucagon - inc cAMP - inc PKA

25. What is the amino acid precursor for GABA and glutathione
Glutamate
Wernicke - korsakoff - dry and wet beriberi
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Malonyl coa

26. What causes biotin def
Histidine
Antibiotic use or excessive ingestion of raw eggs
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Acetyl - CoA to malonyl - CoA (2C to 3C)

27. Which bond is stronger AT or CG and why? What is the laboratory consequence of this?
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Ile - phe - thr - trp
CG- 3 > AT-2 - More CG content - melting point goes up
Muscle

28. Which direction does kinesin go
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Protective against malaria
Neg to pos
Cri du chat

29. What happens in vit D def
FAP
Binds to LDL receptor - mediates VLDL secretion
Must be both activated and inactivated for cell cycle to progress
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)

30. How does chloramphenicol work
Cre - lox system
SnRNPs
Inhibits 50S peptidyltransferase
Palate - facial and cardiac defects

31. What components come together to make S- adenosyl methionine
Arg - lys - his - arg is most basic - has has no charge at body pH
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Base + ribose
ATP and methionine

32. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
Neither of 2 alleles is dominant - blood groups
FMR1 gene - methylation - associated with chromosomal breakage
RER
No

33. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
Fibrofatty replacement of muscle - cardiac myopathy
Inc Cl - in sweat
Q -
Polycystic liver disease - berry aneurysm - mitral valve prolapse

34. What does the start codon code for in eukaryotes and prokaryotes
Eu - methionine - pro - formyl - methionine
Dopamine beta hydroxylase
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
IMP precursor

35. Which aspect of the spliceosome do patients with lupus make antibodies against
Blood - bone marrown - amniotic fluid - placental tissue
SnRNPs
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
ADPKD

36. What leads to the deletion of the dystrophin gene in duchenne's muscular dystrophy
X linked frame shif mutation
MEN - 2A and 2B with ret gene
Pyruvate to oxaloacetate (3C to 4C)
No

37. What substance in egg whites binds biotin
Avidin
HDL
Blood - bone marrown - amniotic fluid - placental tissue
Fibroblast

38. What enzyme esterifies 2/3 of plasma cholesterol
Cofactor for LPL
Kwashiorkor - small child with swollen belly
Chylomicrons
LCAT (lecithin cholesterol acyltransferase)

39. What does glycosylation of pro alpha chian yield and What is the structure
Elastase - inhibited by alpha1 antitrypsin
GAA
Procollagen - triple helix of 3 alpha collagen chains
Glycine

40. What does a southern blot use as its sample
Inc Cl - in sweat
Essential fructosuria - fructokinase AR
DNA
Disease

41. What is the function and name of vit B6
Citrate - acetyl coa from mito to cyto
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
Liver - also in kidney and gut epithelium
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer

42. What causes Hartnup's disease
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Bone - skin - tendon - dentin - fascia - cornea - late wound repair

43. Describe the structure of cilia
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
9+2 arrangement of microtubules
Abnormal protein folding - degradation before reaching cell surface
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)

44. Broadly - What can cause fat - soluble vitamin deficiencies
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Malapsorption syndromes like sprue or CF or mineral oil intake
HVA
1 ring

45. Describe robertsonian translocation
Modifies N- oligosaccharides
No - its non homologous
Creat a nick in the helix to relieave supercoils created during replication
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22

46. In a marathon Where does energy come from
Dec DNA - dec lymphos leads to SCID
CAG
Kidney - ears - eyes
Glycogen and FFA oxidation; glucose conserved for final sprinting

47. bilateral acoustic schwannomas - juvenile cataracts
NF2 on chromosome 22
TTP
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
1 -25 OH2 D3 = calcitriol

48. What order kinetics does EtOH dehydrogenase have
Neural tube
Zero
Glycine
Males are infertile due to bilateral absence of vas deferens

49. What converts limit dextran to glucose
NAD+
Debranching enzyme
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Biotin

50. What converts DOPA to dopamine
Inc glucagon - inc cAMP - inc PKA
Colchicine
Terminal regions - tropocollagen
Dopa decarboxylase