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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 are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
Histidine
Cleft palate - cardiac abnl - pregs test
Neurofibromatosis type 1 (von Recklinghausens disease)
DTMP

2. What is a silent mutation
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
ADPKD
Attachment of ubiquitin to defective proteins tag them for breakdown
Same AA - often base change in 3rd position of codon (tRNA wobble)

3. Describe the replication fork
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Two
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration

4. What does a mischarge tRNA do
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Reads usual codon but inserts wrong AA
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL

5. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Mcardle's - skeletal muscle glycogen posphorylase
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Intermediate filaments
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

6. What is the treatment for orotic aciduria
Proton gradient
Isocitrate dehydrogenase
Oral uridine administration
Arginine

7. What enzyme converts glucose 1 p to UDP glucose
UDP glucose pyrophosphorylase
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
By inhibiting formation of the initiation complex and cause misreading of mRNA
Prokaryotic only - degrades RNA primer and fills in the gap with DNA

8. congenital deficiency of homogentisic acid oxidase in the degradative pathway of tyrosine to fumarate leading to dark connective tissue - brown pigmented sclera - urine turns black on standing - dz and worst complication
Alkaptonuria - may have debiliating arthralgias
Ketone - methyl
Promotor - TATA box - and CAAT box - AT rich
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation

9. What is I cell disease
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Tryosine hydroxylase
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor

10. what happens in acyl coa dehyrdogenase def
High output cardiac failure - dilated cardiomyopathy - edema
Hypoxanthine to xanthing and xanthine to uric acid
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Inc dicarboxylic acids - dec in glucose and ketones

11. What are the complications/signs of familial hypercholesterolemia
ATP hyrdolysis couple to energetically unfavorable rxns
17 - 17 letters in von Recklinghausen
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Facial flushing

12. What collagen type is most frequently affected in ehlers danlos and What are common complications
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
III - joint dislocation - anuerysms - organ rupture
Acetyl - CoA to malonyl - CoA (2C to 3C)
Adds an inorganic phosphate onto substrate without using ATP

13. What is the energy source for tRNA actication (charging)
ATP
AMP - fructose 2 -6 BP
Inhibits 50S peptidyltransferase
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid

14. What do def in in enzymes of gluconeogenesis cause
Hypoglycemia
Makes RNA primer on which DNA poly III can initiate replication
Chylomicrons
Familial hypercholesterolemia - hyperlipidemia type IIA

15. 90% of ADPKD cases are due to a mutation In what gene
APKD1 on chromosome 16
RER
CarTWOlage
Glycine

16. facial lesions - hypopigmented 'ash leaf spots -' cortical and retinal hamartomas - seizures - mental retardation - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas - inc risk of astrocytomas
Glucose 6 phosphatase
Tuberous sclerosis
Heterochromatin = HighlyCondensed
Flank pain - hematuria - HTN - progressive renal failure

17. What two proteins make up microtubules and how are they arranged
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Glycine - aspartate - glutamine
Alpha and beta tubulin - dimers have two GTP bound
Proline and glycine (non glycosylated forms)

18. Adenosine deaminase deficiency is an important cause of what immunodeficiency?
Peroxide
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Dec DNA - dec lymphos leads to SCID
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

19. What is the RDE of gluconeogenesis
Fructose 1 -6 bisphosphate
Mebendazole/thiabendazole
Abnormal protein folding - degradation before reaching cell surface
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22

20. What makes up a nucleotide

21. Where is glucokinase found - What are the Km and Vmax - and what induces it
Biotin
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
OTC has hyperammonemia - orotic aciduira does not

22. How do glucagon/epi lead to glycogenolysis
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

23. nucleotide repeat for fredreich's ataxia
Inc melt - dec fluidity
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
GAA
RRNA

24. What other inflammatory process can induce a hemolytic anemia in NADPH defieicnt patients
Infection - free radicals generated by inflammatory response
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
1 ring
Colchicine

25. What 3 steps in RNA processing occur after transcription

26. What is the origin of replication
Particular sequence of DNA where replicatino begins - may be single of multiple
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

27. benign asymptomatic condition with elevated levels of fructose in urine and blood - dz and enzyme
No
Essential fructosuria - fructokinase AR
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

28. What is the results of vit B1 def
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Glycogen phosphorylase
Binds 50S - blocking translocation
Mitochondria

29. What is the purpose of the HMP shunt
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
After citruline
B48 - AIV - CII - E

30. Where are FADH2 electrons transferred to...
Seals.
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
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
Comlex II

31. What is a missense mutation
Changed AA (convservative - new AA is similar in chemical structure)
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Wernicke - korsakoff - dry and wet beriberi
Medial dorsal nucleus of thalamus - mamillary bodies

32. What is the initial transcript called and What is the capped and tailed transcript called
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Attachment of ubiquitin to defective proteins tag them for breakdown
Arg - lys - his - arg is most basic - has has no charge at body pH

33. What is NADPH's role inside RBCs
Flagella - cilia - mitotic spindles
Keep glutathione reduced so it can detoxify free radicals and peroxides
Glycine - aspartate - glutamine
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

34. What is the most common urea cycle disorder and What is the mode of inheritance?
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Carbomoyl phosphate synthetase I
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
RRNA

35. inc glycogen in muscle but can't break it down - painful muscle cramps - myglobinuria with strenuous exercise - dz and enzyme

36. What defects characterize DiGeorge syndrome
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Vincritsine/vinblastine
Thymic - parathyroid and cardiac
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects

37. What enzyme does fructose metabolism bypass to reach glycolysis
PFK - rate limiting enzyme
Glycogen synthase
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
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

38. What is the exception to genetic redundancy
Methionine encode by only 1 codon (AUG)
Comlex II
More than 1 codon may code for the same amino acid
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora

39. What is made fir rNucleotides or deoxyrNucleotides and what enzyme is necessary to convert one to the next
Microtubules
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Ribos first then deoxyribos with ribonucleotide reductase
Von Gierke's - Pompe - Cori - McArdle

40. Why does alpha amanitin cause liver failure and Where is it found
Alpha1 antitrypsin
Inhibits RNA polymerase II - found in death cap mushrooms
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Base + ribose + phosphate (3' -5') phosphodiester bond

41. in a 100 meter sprint Where does energy come from
Stored ATP - creatine phosphate - anaerobic glycolysis
Change resulting in early stop codon
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

42. What does the ELISA test for
Superoxide dismutase
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Antigen - antibody reactivity - can look for antigen or antibody in patients blood

43. In what cell is collagen synthesis initiated
Fibroblast
Vincritsine/vinblastine
Carnitine acyltransferase I
Inc CPK and muscle biopsy

44. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
GAA
Fibrofatty replacement of muscle - cardiac myopathy
Cyclin dependent kinases;constitutive and inactive

45. What does the deletion of the dystrophin gene lead to...
Mutated dystrophin gene - less severe - adolescence
Accelearted muscle breakdown
Enhancers
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

46. Why enzyme breaks down elastin and what enzyme inhibits it
Skin
2pq
Elastase - inhibited by alpha1 antitrypsin
Carnitine acyltransferase I

47. What are the results of CF on male fertility
Oxalacetate
More than 1 codon may code for the same amino acid
Males are infertile due to bilateral absence of vas deferens
De novo pyrimidine synthesis and urea - ornithine transcarbamoyl def in the urea cycle leads to a build of CP - then converted to orotic acid in pyrimidine synthesis pathway

48. How is orotic aciduria inherited
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Biotin
AR
Degredation of TG circulating in chylomicrons and VLDLs

49. What does a phosphorylase do
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
In ER - glucose 6- P to glucose
Adds an inorganic phosphate onto substrate without using ATP
Terminal regions - tropocollagen

50. What are the two possible causes of albinism
LCAT (lecithin cholesterol acyltransferase)
Robertsonian translocation and mosaicism
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Autosomal recessive diseases