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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 amino acid precuror for creatine - urea and nitric oxide
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Arginine
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Cartilage - hyaline - vitreous body - nucleus pulposus

2. What is the trinucleotide repeat in fragile X
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
CGG
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
Liver - ovaries - seminal vesicles

3. What is the treatment for dec affinity of cystathionine synthase for pyroxidal phosphate
Phenylethamolamine N methyl transferase
Inc vit B6
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

4. What are the reactants for glycolysis
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
CG- 3 > AT-2 - More CG content - melting point goes up
Glucose - 2Pi - 2ADP - 2NAD+
Thymic - parathyroid and cardiac

5. How do labile celss grow and regenerate and What are examples
Unmethylated - newly synthesized - HNPCC
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
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
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles

6. In eukaryotes - What does RNA poly III make
TRNA
Catabolic processes to carry reducing equivalents away as NADH
Microtubules
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects

7. What are the characteristics of angelmans syndrome and How does it occur
EtOH dehydrogenase and acetaldehyde dehydrogenase
Base + ribose
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele

8. Why does alpha amanitin cause liver failure and Where is it found
Inhibits RNA polymerase II - found in death cap mushrooms
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Infection - free radicals generated by inflammatory response
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles

9. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Type II
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Brittle bone disease - most commonly lead AD with abnl type I collagen causing multiple fractures with minimal trauma - blue sclerae due to translucency of connective tissue over the choroid - hearing loss - dental imperfections due to lack of dentin
APKD1 on chromosome 16

10. What is the amino acid precursor for porphyrin and heme
Degradation of TG remaining in IDL
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
Glycine
African Americans and Asians

11. What happens in the first stage of collagen synthesis - and Where does it happen
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
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor

12. What are the glucogenic essential amino acids
25OHD3
High output cardiac failure - dilated cardiomyopathy - edema
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Met - val - arg his

13. What step begins the urea cycle and What is the enzyme needed - Where does it happen
Neg to pos
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Stored ATP - creatine phosphate - anaerobic glycolysis
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

14. What is the order of severity for the different types of mutations
EtOH dehydrogenase and acetaldehyde dehydrogenase
III - joint dislocation - anuerysms - organ rupture
Change resulting in early stop codon
Nonsense > missense > silent

15. What is the TX for pyruvate dehydrogenase deficiency
Basement membrane or basal lamina
Huntingtons
X linked frame shif mutation
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine

16. What initiates protein synthesis
Asp and Glu
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
After day 1
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex

17. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
CFTR gene - 7 - Phe 508
Facial flushing
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
HGPRT - defective purine salvage - excess uric acid production

18. Type I collagen
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Degredation of dietary TG in small intestine

19. What apolipoprotein is on LDL
L form
B100
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
2pq

20. What is the RDE of glycogen synthesis
2 -4 DNP - aspirin
Glycogen synthase
PCR - denaturation - annealing - elongation
Enhancers

21. Synthesis of vit B3 requires what other vitamin
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Stop codon is recognized by release factor - and completed protein is released from ribosome
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
B6

22. What are the symptoms of vit A def
Phenytoin - MTX - and sulfonamides
Microarrays
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Night blindness - dry skin

23. What causes biotin def
Alkaptonuria - may have debiliating arthralgias
Creat a nick in the helix to relieave supercoils created during replication
Binds to LDL receptor - mediates VLDL secretion
Antibiotic use or excessive ingestion of raw eggs

24. What are CDKs
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Cytosol
Cyclin dependent kinases;constitutive and inactive
Karyotyping

25. Type II cartilage
Deamination
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
CarTWOlage
SnRNPs

26. What is the purpose of the HMP shunt
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Tuberous sclerosis
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates

27. What are the two possible causes of albinism
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Tropoelastin with fibrillin scafolding
P2 +2pq+ = 1

28. What is the energy source for tRNA actication (charging)
ATP
Diphyllobothrium latum
Arg - lys - his - arg is most basic - has has no charge at body pH
Pyruvate - NAD+ - CoA

29. characterize x linked recessive
Oxidized hemoglobin precipiated within RBCs
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
They yield only acetyl - CoA equivalents
UGA - UAA and UAG

30. What is RNAi used for
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
DsRNA promotes degradation of target mRNA knocking down gene expression
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Avidin

31. What is the target of the 3' hydroxyl attack
The triphosphate bond
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Phosphorylation - glycosylation - hydroxylation

32. Describe the pathophys of the aorta in a pt with marfans - and the eyes
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Proline and lysine - vit C
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

33. What does a phosphatase do
LCAT (lecithin cholesterol acyltransferase)
CGG
Liver - also in kidney and gut epithelium
Removes phosphate group from substrate

34. What is the RDE of de novo purine synthesis
Glutamine PRPP amidotransferase
Lacks glucose 6 phophatase
Basement membrane or basal lamina
B12 and folate

35. nucleotide repeat for fragile x
CGG
Histidine
Assistance of upper extremities to stand up
Karyotyping

36. What is the breakdown product of dopamine
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Lacks glucose 6 phophatase
HVA
NADPH

37. What is DNA cloning and How do you do it?
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Dec methionine - inc cystiene - inc B12/folate
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

38. In a marathon Where does energy come from
TTP
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Glycogen and FFA oxidation; glucose conserved for final sprinting

39. What does the start codon code for in eukaryotes and prokaryotes
B100
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Eu - methionine - pro - formyl - methionine

40. What happens in vit D def
Methionine encode by only 1 codon (AUG)
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
THFs

41. What are the physical findings of fragile x syndrome
Fibrofatty replacement of muscle - cardiac myopathy
Diphyllobothrium latum
Glycogen and FFA oxidation; glucose conserved for final sprinting
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

42. What does a defective Cl channel do
Hypoglycemia
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
MRNA
Carbomoyl phosphate synthetase I

43. Why is G6PD def more common among patients of african decent
Protective against malaria
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Defect in fibrillin
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

44. recurrent pulmonary infxns in CF are due to what organisms
Pseudomonas and s aureus
APKD1 on chromosome 16
Neg to pos
Conversion of NE to epi

45. What substances directly inhibit electron transport chain
Post to neg
SnRNPs
Rotenone - CN- - antimycin A - CO
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais

46. Where is hexokinase found - What is its Km and Vmax and what uninduces it
Oxidative and nonoxidative - no ATP produced or used
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Nonsense > missense > silent

47. What are Heinz bodies
B12 and folate
Oxidized hemoglobin precipiated within RBCs
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis

48. What are cyclins
Malonyl coa
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Must be both activated and inactivated for cell cycle to progress
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

49. What fxn does glucokinase serve in the liver
Dopamine beta hydroxylase
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
HMG- CoA reductase

50. What drugs can cause folate def
SNP
Tyrosine
Phenytoin - MTX - and sulfonamides
Proton gradient