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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. nucleotide repeat for fragile x
CGG
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
P+q = 1

2. What does cytokeratin stain for
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Epithelial cells
Fibroblast
Enhancers

3. How do fluoroquinolones work
Inhibit DNA gyrase specific for prokaryotic topoisomerase
RNA
Glycine - aspartate - glutamine
CG- 3 > AT-2 - More CG content - melting point goes up

4. What is the rate limiting enzyme in cholesterol synthesis
Poly A polymerase - signal is AAUAA
Degredation of TG circulating in chylomicrons and VLDLs
Mucus secreting globlet cells and antibody secreting plasma cells
HMG- CoA (HMG- CoA to mevalonate

5. What is locus heterogeneity and give an example
Asp and Glu
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Chronic granulomatous disease - no respiatory burst - no formatino of ROS

6. What is the RDE of glycogenolysis
B6
Glycogen phosphorylase
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Glutamine PRPP amidotransferase

7. Is there any requirement for homology in NHEJ
Heterochromatin = HighlyCondensed
No - its non homologous
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

8. Name 5 drugs that interfere with nucleotide synthesis
Read from a fixed starting point as a continuous sequence of bases
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
HMG- CoA reductase
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR

9. What substance inside the cells replenishes NADPH
G6PD
Inhibits RNA polymerase II - found in death cap mushrooms
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Von hippel lindau - 3

10. What does hartnups disease cause
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Eu - methionine - pro - formyl - methionine
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

11. What happens in vit B2 def
B12 and folate
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)

12. What does apoCII do
Cofactor for LPL
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Glycogenolysis to form glucose

13. What are the functinos of vitamin A
Histidine
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
RRNA

14. What is the most common urea cycle disorder and What is the mode of inheritance?
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
2 rings
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Oxalacetate

15. Who typically has lactase def
African Americans and Asians
Disorder of aromatic amino acid metabolism
Procollagen - triple helix of 3 alpha collagen chains
Cyclin dependent kinases;constitutive and inactive

16. What happens on the nonoxidative arm of the HMP shunt and What is the key enzyme and cofactor
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
The triphosphate bond

17. What is pleiotropy and given an example
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Oral uridine administration
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

18. What is regeneration of methionine depedent on...
B12 and folate
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
CGG
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

19. What does DNA ligase do
Seals.
Inc melt - dec fluidity
Zero
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles

20. What happens at the smooth ER
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Pyruvate to oxaloacetate (3C to 4C)
Site of steroid synthesis and detoxification of drugs and poisons
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine

21. What converts dopamine to NE
Alpha1 antitrypsin
Dopamine beta hydroxylase
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

22. How does abetalipoproteinemia present and What is the defect
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
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
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

23. What are the results of CF on male fertility
75 to 90 - cloverleaf
Males are infertile due to bilateral absence of vas deferens
B100 and E
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

24. How does chloramphenicol work
Adenosine to inosine
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Inhibits 50S peptidyltransferase

25. What is chediak higashi
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Free ribosomes
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy

26. What are the physical findings of fragile x syndrome
SnRNPs and other proteins
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
Enhancers
Nissl body - enzyme and NTs

27. Why can't muscle produce in gluconeogenesis
DTMP
SnRNPs and other proteins
Lacks glucose 6 phophatase
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination

28. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
B6
Rb and p53
Cri du chat
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia

29. The pyruvate dehydrogenase complex serves In what reaction: products
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Degredation of TG circulating in chylomicrons and VLDLs
Acetly- CoA - CO2 - NADH

30. What substances are uncouling agents
Mebendazole/thiabendazole
Fasting
Proton gradient
2 -4 DNP - aspirin

31. How do odd chain fatty acids participate in gluconeogenesis
Disease
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

32. What is the order of severity for the different types of mutations
HMG- CoA synthase
DsRNA promotes degradation of target mRNA knocking down gene expression
Nonsense > missense > silent
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

33. What enzyme catalyzes the rxn from pyrvuate to Acetyl - CoA and what inhibits it
Glycogenolysis to form glucose
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Exons
Polyneuritis - symmetrical muscle wasting

34. What lab procedure is used to amplify desired fragment of DNA and What are the 3 steps
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
PCR - denaturation - annealing - elongation
Rotenone - CN- - antimycin A - CO
Cri du chat

35. What makes up a nucleoside
Base + ribose
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
Liver - also in kidney and gut epithelium
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

36. What does desmin stain for
Muscle
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Change resulting in early stop codon
Superoxide dismutase

37. In which structures do you find microtubules
Flagella - cilia - mitotic spindles
Epithelial cells
More than 1 codon may code for the same amino acid
32 - malate aspartate shuttle

38. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
Chylomicrons
Oxidizes substrate
Accelearted muscle breakdown
Peroxide

39. What is the amino acid precursor for GABA and glutathione
Acetoacetate and beta hydroxybutyrate
Glutamate
9+2 arrangement of microtubules
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects

40. ADPKD is associated with What additional conditions
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Alpha 1 -6 and alpha 1 -4
Polycystic liver disease - berry aneurysm - mitral valve prolapse
NF2 on chromosome 22

41. NADPH are used In what 4 things
Active secretion in lungs and GI - reabsorbs in skin
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
X- linked recessive
NAD+

42. What are the findings in Lesch - Nyhan
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Familial hypercholesterolemia - hyperlipidemia type IIA
Adds 2 carbon with the help of biotin
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis

43. What does apoA 1 do
Essential fructosuria - fructokinase AR
Mitochondria
Nine
Activates LCAT

44. What happens in termination of proteins synthesis
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Stop codon is recognized by release factor - and completed protein is released from ribosome
Oxidizes substrate
Dermatitis - glossitis - and diarrhea

45. What is the active form of vit D
1 -25 OH2 D3 = calcitriol
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
CAG
Same as sprint + OXPHOS

46. Mediates reverse cholesterol transport from periphery to liver - acts as respository for apoC an apoE - secreted from both liver and small intestine
HDL
Phenylethamolamine N methyl transferase
Neither of 2 alleles is dominant - blood groups
Supply sufficient glucose to brain and RBCs and to preserve protein

47. progressive neurodegeneration - developmental delay - cherry red spot on macula - lysosomes with onion skin - NO hepatosplenomegaly
Intermediate filaments
Hyperlipidemia
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Carnitine acyltransferase I

48. What happens in folate def
After citruline
Read from a fixed starting point as a continuous sequence of bases
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs

49. What are the blood glucose levels maintained by for days 1-3
Neural tube
Elastase - inhibited by alpha1 antitrypsin
Transmitted only through mother - all offspring of affected females may show signs of disease
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)

50. What enzyme does fructose metabolism bypass to reach glycolysis
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
VMA
PFK - rate limiting enzyme
Phosphorylation - glycosylation - hydroxylation