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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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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What are the fat soluble vitamins and What does their absorption depend on...
Colchicine
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Neuralgia
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome

2. What substances are uncouling agents
Nissl body - enzyme and NTs
Mitochondria
2 -4 DNP - aspirin
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration

3. What is imprinting and give an example

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4. What enzyme converts adenine to AMP
Each codon specifies only 1 amino acid
APRT + PRPP
B48 - AIV - CII - E
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms

5. What is loss of heterozygosity and give an example
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
Creat a nick in the helix to relieave supercoils created during replication
Sulfation
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms

6. What does vit C def cause
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Fibroblast
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

7. Where is EtOH dehydrogenase located
Arginine
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
CAG - 4
Cytosol

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

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9. What does the start codon code for in eukaryotes and prokaryotes
Skin
SNP
Eu - methionine - pro - formyl - methionine
Malabsorption and steatorrhea (ADEK)

10. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

11. In which single strand DNA repair mechanism do specific endonucleases release the oligonucTIDE containing bases and DNA poly and ligase fill and reseal - and what disease occures when this is mutated
Catabolic processes to carry reducing equivalents away as NADH
Evident in first few days of life - can present last onest - excess carbamoyl phosphate converted to orotic acid - orotic acid in blood and urine - dec BUN and symptoms of hyerpammonemia
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Krabbes - galactocerebrosidase - galactocerebroside - AR

12. Name as many x- linked recessive disorders as you can

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13. What causes maple syrup urine disease and What does it lead to...
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
CFTR gene - 7 - Phe 508
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Dec in alpha ketoacid dehydrogenas leading to blocked degredation of branches amino acids like Ile - Leu - and Val - severe CNS defects mental retardation and death

14. What kind of branches do glycogen branches have
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Alpha 1 -6 and alpha 1 -4
Base + ribose
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR

15. peripheral neuropathy - developmental delay - optic atrophy - glopoid cells
Anabolic processes as a supply of reducing equivalents
Krabbes - galactocerebrosidase - galactocerebroside - AR
Hepatic glycogenolysis - adipose tissue release of FFA - muslce and liver FFA - hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and proprionyl - coA (odd chain FFA)
Dopa decarboxylase

16. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
FAP
Mcardle's - skeletal muscle glycogen posphorylase
Malapsorption syndromes like sprue or CF or mineral oil intake
Wernicke - korsakoff - dry and wet beriberi

17. pyruvate carboxylase catalyzes what rxn
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Pyruvate to oxaloacetate (3C to 4C)
Von gierkes - glucose 6 phosphatase
Assistance of upper extremities to stand up

18. What does vit B3 def result in
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Intermediate filaments
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin

19. What does SAM do
Euchromatin
After citruline
Transfers methyl units
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

20. In which state is FBPase -2 active
Tryptophan
Tryosine hydroxylase
Fasting
Unwinds DNA template at replcation fork

21. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
Euchromatin
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Fed
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects

22. What activates the pyruvate dehydrogenase complex
Defect in fibrillin
HMG- CoA (HMG- CoA to mevalonate
Exercise: inc NAD/NADH - inc ADP - inc Ca
Promotor - TATA box - and CAAT box - AT rich

23. What does an umabiguous genetic code refer to...
Malabsorption and steatorrhea (ADEK)
Ribos first then deoxyribos with ribonucleotide reductase
Each codon specifies only 1 amino acid
Elastase - inhibited by alpha1 antitrypsin

24. What is the physiologic role of dystrophin
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Glutamine PRPP amidotransferase
MEN - 2A and 2B with ret gene
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

25. What enzyme converts phenylalanine to tyrosin
Nine
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
Phenylalanine hydroxylase
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

26. What is Gowers maneuver
Assistance of upper extremities to stand up
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Degredation of TG circulating in chylomicrons and VLDLs
THFs

27. What does apoE do
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Degradation of TG remaining in IDL
Mediates extra remnant take up
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora

28. Which aspect of the spliceosome do patients with lupus make antibodies against
Terminal regions - tropocollagen
HMP shunt
SnRNPs
PMNs

29. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Von hippel lindau - 3
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
HGPRT - defective purine salvage - excess uric acid production

30. In addition to fructose and galactose - what sugards should be excluded from the diets of patients with disorders of fructose or galactose metabolism
Glycogen synthase
Sucrose = glucose + fructose - lactose = glucose + galactose
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
G6PD

31. What happens in elongation of protein synthesis

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32. When does aspartate enter the urea cycle
Cartilage - hyaline - vitreous body - nucleus pulposus
PCR - denaturation - annealing - elongation
Methionine encode by only 1 codon (AUG)
After citruline

33. How do aminoglycosides work
EtOH dehydrogenase and acetaldehyde dehydrogenase
By inhibiting formation of the initiation complex and cause misreading of mRNA
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Consesus sequenec of base pairs

34. What does a southern blot use as its sample
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Dopa decarboxylase
DNA

35. What does GFAP stain for
Hereditary spherocytosis
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Neuralgia
Initiate chains

36. What is the RDE of TCA cycle
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Vincritsine/vinblastine
Isocitrate dehydrogenase

37. What happens in vit D def
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Carnitine shuttle - acyl - coa from cyto to mito
DTMP
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)

38. What are pyrimidines made from
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Dec methionine - inc cystiene - inc B12/folate
Orotate precursor - with PRPP added later

39. What does high cholesterol or long saturated fatty acid content do to the melting temperature and fluidity
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Inc Cl - in sweat
Inc melt - dec fluidity
VMA

40. cytoskeletal elements in micorvilli - muscle contracting fibers - cytokenesis - adherens jxns
Actin and myosin
RNA
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Phenytoin - MTX - and sulfonamides

41. What does hepatic TG lipase do
Degredation of TG circulating in chylomicrons and VLDLs
2 -4 DNP - aspirin
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Degradation of TG remaining in IDL

42. depression - progressive dementia - choreiform movements - caudate atrophy and dec levels of GABA and ACH in the brain
Base + ribose
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Huntingtons
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene

43. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Stored ATP - creatine phosphate - anaerobic glycolysis
Promotor - TATA box - and CAAT box - AT rich
IDL
Karyotyping

44. peripheral neuropathy of hands/feet - angiokeratomas - CV/renal disease - dz - def enzyme - acc substrate - inherit
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Muscle
Acetly- CoA - CO2 - NADH

45. What is the TX for PKU
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Consesus sequenec of base pairs
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

46. Describe the replication fork
They yield only acetyl - CoA equivalents
Particular sequence of DNA where replicatino begins - may be single of multiple
Y shaped region along the DNA template where leading nad lagging strands are synthesized
MRNA

47. Do balanced translocations cause abnl phenotype
Vit K antagonist
No
Post to neg
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

48. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Liver - also in kidney and gut epithelium
Cleft palate - cardiac abnl - pregs test
Ketone - methyl

49. How is ATP used by the cell
Modifies N- oligosaccharides
Proline and glycine (non glycosylated forms)
ATP hyrdolysis couple to energetically unfavorable rxns
Targets the proteins for lysosome

50. What enzyme does fructose metabolism bypass to reach glycolysis
Cofactor for LPL
PFK - rate limiting enzyme
2pq
Glycine