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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. How do microtubules grow and collapse
Grows slowly - collapses quickly
Neural tube
Type II
Bone - skin - tendon - dentin - fascia - cornea - late wound repair

2. protein malnutrition resulting in skin lesions - edema and liver malfxn
Orotate precursor - with PRPP added later
Kwashiorkor - small child with swollen belly
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Proline and lysine - vit C

3. 1 g of protein or cabrohydrate = ?kcal
Four
Conversion of NE to epi
Oral uridine administration
Eu - methionine - pro - formyl - methionine

4. What step of uric acid synthesis does xanthine oxidase catalyze
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year
Liver - also in kidney and gut epithelium
X- linked recessive
Hypoxanthine to xanthing and xanthine to uric acid

5. What is the rate limiting enzyme in cholesterol synthesis
Supply sufficient glucose to brain and RBCs and to preserve protein
HMG- CoA (HMG- CoA to mevalonate
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
Post to neg

6. How do aminoglycosides work
By inhibiting formation of the initiation complex and cause misreading of mRNA
Lariat shape in order and remove intron precisely and join 2 exons
DTMP
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side

7. What happens at the smooth ER
Particular sequence of DNA where replicatino begins - may be single of multiple
Site of steroid synthesis and detoxification of drugs and poisons
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

8. What do DNA topoisomerases do
Cofactor for LPL
Base + ribose + phosphate (3' -5') phosphodiester bond
Disease
Creat a nick in the helix to relieave supercoils created during replication

9. What is the longest time of RNA and shortest
MRNA - tRNA
Skin
Met - val - arg his
1 kind with multiple subunits

10. What is the RDE of de novo purine synthesis
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Flank pain - hematuria - HTN - progressive renal failure
Biotin
Glutamine PRPP amidotransferase

11. What are the products for glycolysis
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Von hippel lindau - 3
Not all individuals with a mutant genotype show the mutant phenotype
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR

12. What rxn does propionyl - CoA carboxylase catalyze
Tryptophan
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side
Alpha and beta tubulin - dimers have two GTP bound

13. What is the amino acid precursor for porphyrin and heme
Tropoelastin with fibrillin scafolding
More than 1 codon may code for the same amino acid
Glycine
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells

14. What is the RDE of glycogen synthesis
Oxidative and nonoxidative - no ATP produced or used
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Glycogen synthase
Acetyl - CoA carboxylase (ACC)

15. What is the defect in I- hyperchylomicronemia
Microarrays
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
CG- 3 > AT-2 - More CG content - melting point goes up
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

16. What converts limit dextran to glucose
Lysine and arginine
Debranching enzyme
RRNA
Creat a nick in the helix to relieave supercoils created during replication

17. Outside the fibroblast What part of procollagen is cleaved and What is it transformed into
Elastase - inhibited by alpha1 antitrypsin
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Terminal regions - tropocollagen
Protective against malaria

18. The pyruvate dehydorgenase complex serves In what reaction: reactants
Pyruvate - NAD+ - CoA
B-100 - CII and E
Inc insulin - dec cAMP - dec PKA
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis

19. What 3 steps in RNA processing occur after transcription

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20. Describe robertsonian translocation
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
FMR1 gene - methylation - associated with chromosomal breakage
Liver hepatocytes and steroid producing cells of the adrenal cortex
Flank pain - hematuria - HTN - progressive renal failure

21. What are possilbe presentation for galactokinase def
Acetoacetate and beta hydroxybutyrate
Failure to track objects or develop a social smile
Neuralgia
Robertsonian translocation and mosaicism

22. How are the many staggered tropocollagen molecules reinforced
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Biotin
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Ca/calmodulin in muscle to coordinate with muscle activity

23. What is the activated carrier for aldehyddes
Two
TTP
B100
Mitochondria

24. What lab technique is use to profile gene expression levels of thousands of genes simultaneously to study certain diseases and treatments
The triphosphate bond
Microarrays
Abnormal protein folding - degradation before reaching cell surface
Acetyl - CoA

25. metaphse chromosomes are stained - ordered and numbered according to morphology - size - arm length ratio - banding pattern
Zero
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Karyotyping
Each codon specifies only 1 amino acid

26. What is the treatment for dec affinity of cystathionine synthase for pyroxidal phosphate
Protein kinase A
Epithelial cells
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Inc vit B6

27. How does ouabain work
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Protective against malaria
Inhibits the Na/K pump by binding the K side
Polyneuritis - symmetrical muscle wasting

28. What is made fir rNucleotides or deoxyrNucleotides and what enzyme is necessary to convert one to the next
Modifies N- oligosaccharides
Inc melt - dec fluidity
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
Ribos first then deoxyribos with ribonucleotide reductase

29. What occurs to oxaloacetate in starvation and DKA
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Stop codon is recognized by release factor - and completed protein is released from ribosome
Removes phosphate group from substrate
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles

30. What does lipoprotein lipase do
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
NAD+
Degredation of TG circulating in chylomicrons and VLDLs
Transmitted only through mother - all offspring of affected females may show signs of disease

31. What are the findings with homocystinuria and What amino acid is needs to be supplemented
CAG
Von Gierke's - Pompe - Cori - McArdle
LDL
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

32. What is the defect in II A familial hypercholesterolemia
Fibrofatty replacement of muscle - cardiac myopathy
Two
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
ATP hyrdolysis couple to energetically unfavorable rxns

33. Very Poor Carbohydrate Metabolism stands for 4 of the glycogen storage diseases - What are thy

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34. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
HGPRT - defective purine salvage - excess uric acid production
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
1/4 of offspring from 2 carrier parents are affected - often enzyme def - usually only seen in 1 generation - often more sever than AD - presents in childhood

35. Why enzyme breaks down elastin and what enzyme inhibits it
Achondroplasia
Met - val - arg his
Elastase - inhibited by alpha1 antitrypsin
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

36. What is the main source of folate
Adds 2 carbon with the help of biotin
Foliage - small reserve in liver - eat green leaves
OTC has hyperammonemia - orotic aciduira does not
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)

37. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Von hippel lindau - 3
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

38. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Phenylethamolamine N methyl transferase
Alpha 1 -4 glucosidase
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
SnRNPs and other proteins

39. What are Heinz bodies
Fibroblast
Oxidized hemoglobin precipiated within RBCs
Base + ribose + phosphate (3' -5') phosphodiester bond
Collagen

40. Which anticancer drugs work on microtubules
Von Gierke's - Pompe - Cori - McArdle
Lactate
Vincritsine/vinblastine
Malonyl coa

41. what happens in acyl coa dehyrdogenase def
Core proteins
Tryptophan
Fed
Inc dicarboxylic acids - dec in glucose and ketones

42. Why does alpha amanitin cause liver failure and Where is it found
TTP
Inhibits RNA polymerase II - found in death cap mushrooms
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Eu - methionine - pro - formyl - methionine

43. What enzyme does fructose metabolism bypass to reach glycolysis
PFK - rate limiting enzyme
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin

44. What form of amino acids are found in proteins
N to C
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
3' end (with CCA)
L form

45. What does the golgi add to serine and threonine residues
Coenzyme A - lipoamide
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Mediates chylomicron secretion
O- oligosaccharaides

46. What does hepatic TG lipase do
Cre - lox system
Degradation of TG remaining in IDL
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
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

47. Gene imprinting implies that How many alleles are active at a single locus
HMG- CoA synthase
One
PMNs
Lysine and leucine

48. What is the structure of elastin
Tropoelastin with fibrillin scafolding
Oxidizes substrate
Tryptophan
Oxidized hemoglobin precipiated within RBCs

49. What is the amino acid precuror for creatine - urea and nitric oxide
Modifies N- oligosaccharides
Arginine
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
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

50. What substances directly inhibit electron transport chain
Specific glycosylases - AP endonuclease
Oxalacetate
Rotenone - CN- - antimycin A - CO
5' to 3'