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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. In what cell is collagen synthesis initiated
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Fibroblast
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

2. What is kartageners syndrome
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
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
NADH - NADPH - FADH2

3. Is there any requirement for homology in NHEJ
Arginine
No - its non homologous
Night blindness - dry skin
Inhibits RNA polymerase II - found in death cap mushrooms

4. developmental delay - gargoylism - airway obstruction - corneal clouding - hepatosplenomegaly
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Kwashiorkor - small child with swollen belly
Covalent cross - linking by lysyl oxidase to make collagen fibrils

5. What are the fat soluble vitamins and What does their absorption depend on...
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
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
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Protein kinase A

6. What does the CFTR channel do in the lungs - GI tract and skin
Deamination
Marfans
Von Gierke's - Pompe - Cori - McArdle
Active secretion in lungs and GI - reabsorbs in skin

7. In addition to fructose and galactose - what sugards should be excluded from the diets of patients with disorders of fructose or galactose metabolism
Alpha 1 -4 glucosidase
Flagella - cilia - mitotic spindles
Sucrose = glucose + fructose - lactose = glucose + galactose
Facial flushing

8. How does patients present with ADPKD
Inc melt - dec fluidity
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Flank pain - hematuria - HTN - progressive renal failure
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies

9. What is the results of vit B1 def
Von gierkes - glucose 6 phosphatase
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

10. What is disulfiram used for
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome

11. Why is albinism inheritnace varialbe due to...
Locus heterogeneity - ocular albinism is x- linked recessive
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
HMG- CoA (HMG- CoA to mevalonate
HDL

12. What are the irreversible enzymes of gluconeogenesis
Purines= A - G pyrimidine = C - T (U)
Cleft palate - cardiac abnl - pregs test
Inc dicarboxylic acids - dec in glucose and ketones
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

13. What are the findings in Lesch - Nyhan
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
AR
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Citrate - acetyl coa from mito to cyto

14. What is the RDE of de novo purine synthesis
Glutamine PRPP amidotransferase
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Glycogen and FFA oxidation; glucose conserved for final sprinting
II - VII - IX - X (1972) protein C and S

15. What does a defective Cl channel do
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
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

16. Mediates reverse cholesterol transport from periphery to liver - acts as respository for apoC an apoE - secreted from both liver and small intestine
ATP hyrdolysis couple to energetically unfavorable rxns
5' to 3'
HDL
HMG- CoA (HMG- CoA to mevalonate

17. What tissues have only aldose reductase
Schwann cells - lens - retina - kidneys
Cleft palate - cardiac abnl - pregs test
Adds 2 carbon with the help of biotin
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis

18. What is the mutation in beckers muscular dystrophy - What is the severity and time of onset
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
Mutated dystrophin gene - less severe - adolescence
Removal of N or C termal propeptides from zymogens to generate mature proteins
Removes phosphate group from substrate

19. delivers hepatic TGs to peripheral tissue - secreted by liver
Deamination
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
VLDL
OTC has hyperammonemia - orotic aciduira does not

20. Where is PEP carboxykinase found - What does it do - and What does it require
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Must be both activated and inactivated for cell cycle to progress
Glucose - 2Pi - 2ADP - 2NAD+

21. Why is G6PD def more common among patients of african decent
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Protective against malaria
Anabolic processes as a supply of reducing equivalents
30 - 50 - 70

22. What are the two possible causes of albinism
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
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
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells

23. What does the golgi assemble proteoglycans from
Degredation of dietary TG in small intestine
EtOH dehydrogenase and acetaldehyde dehydrogenase
Core proteins
Ca/calmodulin in muscle to coordinate with muscle activity

24. What lab procedure is used to amplify desired fragment of DNA and What are the 3 steps
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Adds 2 carbon with the help of biotin
Pyruvate to oxaloacetate (3C to 4C)
PCR - denaturation - annealing - elongation

25. What are cyclins
Wernicke - korsakoff - dry and wet beriberi
Malabsorption and steatorrhea (ADEK)
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

26. What are uncoupling agents
Inc permeability of membrane causing a dec in proton gradient and inc in O2 consumption - ATP synthesis stops - but electron transport continues to produce heat
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
AR

27. How do you diagnose CFTR
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Inc Cl - in sweat
Robertsonian translocation and mosaicism
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR

28. What enzyme turns ROS to H2O2
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Mucus secreting globlet cells and antibody secreting plasma cells
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Superoxide dismutase

29. In eukaryotes - What does RNA poly I make
AMP - fructose 2 -6 BP
Modifies N- oligosaccharides
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
RRNA

30. What does glycosylation of pro alpha chian yield and What is the structure
Alpha 1 -4 glucosidase
Procollagen - triple helix of 3 alpha collagen chains
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Purines= A - G pyrimidine = C - T (U)

31. What does a kinase do
Von hippel lindau - 3
Peroxide
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Uses ATP to add high energy phophate group onto substrate

32. A small proportion of Down syndrome is due to What two genetic events
ATP - citrate
Polyneuritis - symmetrical muscle wasting
Pyruvate to oxaloacetate (3C to 4C)
Robertsonian translocation and mosaicism

33. Which are the basic amino acids
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Arg - lys - his - arg is most basic - has has no charge at body pH
Arginine

34. Broadly - What can cause fat - soluble vitamin deficiencies
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Superoxide dismutase
Glycolysis and aerobic respiration
Malapsorption syndromes like sprue or CF or mineral oil intake

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

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36. 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
Leu - lys
Dermatitis - enteritis - alopecia - adrenal insuff
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Biotin

37. What is the RER called in neurons and What is made there
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Nissl body - enzyme and NTs
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
Enhancers

38. Patients with chronic granulomatous disease are at increased risk of infection From which kind of organisms
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Ketone - methyl
OTC has hyperammonemia - orotic aciduira does not

39. What is the treatment for orotic aciduria
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
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
Oral uridine administration
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

40. What is the amino acid precuror for creatine - urea and nitric oxide
Arginine
HMG- CoA synthase
Asp and Glu
Basement membrane or basal lamina

41. What converts limit dextran to glucose
Debranching enzyme
Pseudomonas and s aureus
Cyclin dependent kinases;constitutive and inactive
Marasmus - muscle wasting

42. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Robertsonian translocation and mosaicism
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
FMR1 gene - methylation - associated with chromosomal breakage
HGPRT - defective purine salvage - excess uric acid production

43. What makes up a nucleotide

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44. What does a western blot use for its sample
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
FAP
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Protein

45. What two cells are particularly rich in RER
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Tryptophan
Mucus secreting globlet cells and antibody secreting plasma cells
Grows slowly - collapses quickly

46. What is the amino acid precursor for porphyrin and heme
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Glycine
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Schilling test

47. What is the amino acid precursor for GABA and glutathione
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
Inc glucagon - inc cAMP - inc PKA
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Glutamate

48. What is the energy source after day 3 of starvation
Protein
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Adipse tissue stores - keton bodies become the main source of energy fo the brain and heart - after these are depleted - vital protein degradation accelerates - leading to organ failure and death
Silencers

49. What other complex is similar to the pyruvate dehydrogenase complex in that it has the same co - factors and generates succinyl - CoA
Alpha - ketoglutarate dehydrogenase complex
Comlex II
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Phenylalanine hydroxylase

50. What is the treatment for cystathionine synthase def
APKD1 on chromosome 16
Oxalacetate
Mutated dystrophin gene - less severe - adolescence
Dec methionine - inc cystiene - inc B12/folate