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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 enzyme adds Cl - to the H202 to makes bleach
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Core proteins
Myeloperoxidase
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

2. What is the activated carrier for methyl groups
Met - val - arg his
SAM
Vincritsine/vinblastine
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais

3. What is the energy source in the fed state right after a meal
Wrinkles and acne
Glycogen phosphorylase
Base + ribose
Glycolysis and aerobic respiration

4. Wgat substances directly inhibit mitochondrial ATPase - causing an inc in proton gradient - no ATP because pump is stopped
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Oligomycin
Eu - methionine - pro - formyl - methionine
FAP

5. What is the RER called in neurons and What is made there
Nissl body - enzyme and NTs
Seals.
Krabbes - galactocerebrosidase - galactocerebroside - AR
Karyotyping

6. What are the clinical features of I cell diesase
Acetyl - CoA
Dermatitis - enteritis - alopecia - adrenal insuff
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies

7. What converts dopamine to NE
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Peroxide
Dopamine beta hydroxylase

8. protein malnutrition resulting in skin lesions - edema and liver malfxn
Phenylketones in urine
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Kwashiorkor - small child with swollen belly
NADPH

9. Which anti breast cancer drugs work on micortubules
African Americans and Asians
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Paclitaxel
Zero

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

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11. Which bond is stronger AT or CG and why? What is the laboratory consequence of this?
Same AA - often base change in 3rd position of codon (tRNA wobble)
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
NADH - NADPH - FADH2
CG- 3 > AT-2 - More CG content - melting point goes up

12. 90% of ADPKD cases are due to a mutation In what gene
APKD1 on chromosome 16
Mucus secreting globlet cells and antibody secreting plasma cells
Wobble
HGPRT - defective purine salvage - excess uric acid production

13. What is the RDE of fatty acid oxidation
Carnitine acyltransferase I
Orotate precursor - with PRPP added later
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Hyperlipidemia

14. What is the activated carrier for phosphoryl
Night blindness - dry skin
ATP
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Initiate chains

15. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Promotor - TATA box - and CAAT box - AT rich
4 under the floor
RER
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

16. What rxn does propionyl - CoA carboxylase catalyze
Tropoelastin with fibrillin scafolding
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Wobble

17. What do neurofilaments stain for
Free ribosomes
Facial flushing
III - joint dislocation - anuerysms - organ rupture
Neurons

18. What are CDKs
MEN - 2A and 2B with ret gene
Liver - also in kidney and gut epithelium
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Cyclin dependent kinases;constitutive and inactive

19. Where are cytosolic and organellar proteins made
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
Free ribosomes
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue

20. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
Conversion of NE to epi
Exons
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Eu - methionine - pro - formyl - methionine

21. What is the function of biotin
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins

22. What produces NADPH
Unwinds DNA template at replcation fork
Specific glycosylases - AP endonuclease
III - joint dislocation - anuerysms - organ rupture
HMP shunt

23. How does cytosine become uracil
Promotor - TATA box - and CAAT box - AT rich
Deamination
Asp and Glu
Inhibits RNA polymerase II - found in death cap mushrooms

24. what gene is implicated in fragile X syndrome - and What is the mutation
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Exons
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
FMR1 gene - methylation - associated with chromosomal breakage

25. What is imprinting and give an example

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26. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Chylomicrons
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

27. What happens with dry beriberi
Comlex II
Polyneuritis - symmetrical muscle wasting
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia

28. What causes Down syndrome
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Inc CPK and muscle biopsy
Marasmus - muscle wasting
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

29. How do you diagnose CFTR
SAM
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
Inc Cl - in sweat
Fibrofatty replacement of muscle - cardiac myopathy

30. What does DNA ligase do
2 rings
Seals.
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Tyrosine

31. What are bite cells and when do you see them
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
Result from phagocytic removal of heinz bodies my macs - G6PD def
Ca/calmodulin in muscle to coordinate with muscle activity
Failure to track objects or develop a social smile

32. Give an example of a mitochondrial inherited disease
CAG - 4
Acetyl - CoA to malonyl - CoA (2C to 3C)
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Dopamine beta hydroxylase

33. What is the name is fxn of vit B3
Prokaryotic only - elongates leading strand by adding deoxnucTIDE to the 3' end. Elongates lagging strand until it reaches primer of preceeding fragment. 3' to 5' exonuclease activity 'proofreads' each added nucTIDE
Arg - lys - his - arg is most basic - has has no charge at body pH
Basement membrane or basal lamina
Niacin - constituent of NAD and NADP - derived from tryptophan

34. What does degenerate/rundant genetic code refer to...
Sons of heterozygous mothers have 1/2 half chance of being affected - no male to male transmission - and often more severe in males - heterozygous females may be affected
Wobble
More than 1 codon may code for the same amino acid
Cre - lox system

35. What is the treatment for orotic aciduria
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
Oral uridine administration
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Familial hypercholesterolemia - hyperlipidemia type IIA

36. What apolipoproteins are on IDL
B100 and E
Prevent strands from reannealing
Karyotyping
Glycine - aspartate - glutamine

37. Synthesis of vit B3 requires what other vitamin
FMR1 gene - methylation - associated with chromosomal breakage
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
B6

38. What do DNA topoisomerases do
Creat a nick in the helix to relieave supercoils created during replication
Krabbes - galactocerebrosidase - galactocerebroside - AR
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
32 - malate aspartate shuttle

39. What is the defect in cystinuria
High output cardiac failure - dilated cardiomyopathy - edema
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
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
Alcohol version of glucose - can trap glucose in cell - aldose reductase

40. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Kwashiorkor - small child with swollen belly
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR

41. What does the golgi do to sugars in proteoglycans and of selected tyrosine on proteins
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Inc insulin - dec cAMP - dec PKA
Changed AA (convservative - new AA is similar in chemical structure)
Sulfation

42. What happens in vit D def
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
III - joint dislocation - anuerysms - organ rupture
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)

43. What does acetyl - CoA become before becoming palmitate
Degradation of TG remaining in IDL
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive

44. Which step in the de novo purine and pyrimidine synthesis pathway requires just aspartate
Makes RNA primer on which DNA poly III can initiate replication
Proline and glycine (non glycosylated forms)
Orotic acid to UMP
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR

45. nucleotide repeat for fredreich's ataxia
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Base + ribose + phosphate (3' -5') phosphodiester bond
GAA

46. What is the defect in fructose intolerance and What does it cause
Oxidative and nonoxidative - no ATP produced or used
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Alpha 1 -6 and alpha 1 -4
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

47. For eukaryotes - Where does replication begin?
SnRNPs and other proteins
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Mitochondria
Consesus sequenec of base pairs

48. What happens in vit B2 def
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
Rotenone - CN- - antimycin A - CO
Arg and his inc in histones Which bind negatively charged DNA

49. How does warfarin work
Vit K antagonist
Inc melt - dec fluidity
Carnitine shuttle - acyl - coa from cyto to mito
Mediates chylomicron secretion

50. An inability to convert orotic acid to UMP would be caused by a deficiency either of which two enzymes

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