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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 causes Marfan syndrome
Inc Cl - in sweat
Males are infertile due to bilateral absence of vas deferens
Defect in fibrillin
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

2. What does apoA 1 do
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
Pseudomonas and s aureus
Activates LCAT
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR

3. What does apoB48 do
Accelearted muscle breakdown
Protein
Mediates chylomicron secretion
Malonyl coa

4. In which direction is protein synthesized
N to C
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Facial flushing
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

5. What does hartnups disease cause
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Kidney - ears - eyes
ATP - citrate
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes

6. What tissues have both enzymes of sorbitol metabolism
Protective against malaria
Mebendazole/thiabendazole
Liver - ovaries - seminal vesicles
CAG

7. What 3 steps in RNA processing occur after transcription

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8. What is the physiologic role of dystrophin
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Euchromatin
SnRNPs
Ca/calmodulin in muscle to coordinate with muscle activity

9. Gene imprinting implies that How many alleles are active at a single locus
Result from phagocytic removal of heinz bodies my macs - G6PD def
One
Microtubules
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

10. What is the RDE of the HMP shunt
Glucose 6 phosphate dehydrogenase (G6PD)
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
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
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle

11. What are the mRNA stop codons
Purines= A - G pyrimidine = C - T (U)
X- linked recessive
UGA - UAA and UAG
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision

12. What is the amino acid precuror for creatine - urea and nitric oxide
Tropoelastin with fibrillin scafolding
Arginine
Phosphofructokinase 1
Removes phosphate group from substrate

13. What is the activated carrier for electrons
Exercise: inc NAD/NADH - inc ADP - inc Ca
Eu - methionine - pro - formyl - methionine
Alpha 1 -6 and alpha 1 -4
NADH - NADPH - FADH2

14. What is the hardy weinberg allele prevalence
P+q = 1
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Alpha 1 -4 glucosidase
Pseudomonas and s aureus

15. What does DNA poly III do?

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16. What substances are uncouling agents
AR
2 -4 DNP - aspirin
By inhibiting formation of the initiation complex and cause misreading of mRNA
Arg and his inc in histones Which bind negatively charged DNA

17. What metabolic rxns occur in the mitochondria
Binds to LDL receptor - mediates VLDL secretion
Cleft palate - cardiac abnl - pregs test
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
P2 +2pq+ = 1

18. central and peripheral demyelination with ataxia and dementia
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Glucose 6 phosphate dehydrogenase (G6PD)
RER
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive

19. What does a carboxylase do
B-100 - CII and E
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Adds 2 carbon with the help of biotin

20. What happens in folate def
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
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
Free ribosomes

21. What does a western blot use for its sample
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
4 under the floor
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Protein

22. What are the priorities for the body in fasting and starvation
Silencers
Supply sufficient glucose to brain and RBCs and to preserve protein
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
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

23. How many rings do pyrimidines have
5' to 3'
1 ring
Neural tube
CAG

24. How many rings do purines have
Glycine
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
MRNA - tRNA
2 rings

25. What does the TCA cycle produce per 1 acetyl CoA
40 - 60 - 80
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Oxidative is irreversible

26. What does biotin def cause
Dermatitis - alopecia - enteritis
RRNA
CFTR gene - 7 - Phe 508
Malabsorption and steatorrhea (ADEK)

27. How many ATP are created by aerobic metobolism of glucose in muslce via what shuttle
Carbomoyl phosphate synthetase I
30 - glycerol -3- phosphate shuttle
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Inc glucagon - inc cAMP - inc PKA

28. What enzyme degrades a small amount of glycogen in lysosomes
Alpha 1 -4 glucosidase
African Americans and Asians
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
CG- 3 > AT-2 - More CG content - melting point goes up

29. What enzyme esterifies 2/3 of plasma cholesterol
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
LCAT (lecithin cholesterol acyltransferase)
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
NAD+

30. What are the two possible causes of albinism
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Liver and leafy veggies
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells

31. What is the activated carrier for Co2
Nissl body - enzyme and NTs
Result from phagocytic removal of heinz bodies my macs - G6PD def
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
Biotin

32. What is the results of vit B1 def
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)

33. In which state is PFK-2 active
Robertsonian translocation and mosaicism
SnRNPs
Fed
Huntingtons

34. progressive neurodegeneration - developmental delay - cherry red spot on macula - lysosomes with onion skin - NO hepatosplenomegaly
Post to neg
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Terminal regions - tropocollagen

35. Which are the acidic amino acids
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Asp and Glu

36. What are ketone bodies made from - where are they metabolized and how are they excreted
Post to neg
Pseudomonas and s aureus
APKD1 on chromosome 16
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine

37. What are the findings in orotic aciduria
Only processed RNA
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

38. What is Gowers maneuver
NF2 on chromosome 22
Assistance of upper extremities to stand up
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Grows slowly - collapses quickly

39. Where are FADH2 electrons transferred to...
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Comlex II
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

40. In eukaryotes - What does RNA poly III make
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
RER
TRNA
Ribos first then deoxyribos with ribonucleotide reductase

41. How do aminoglycosides work
By inhibiting formation of the initiation complex and cause misreading of mRNA
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Oxalacetate
Myeloperoxidase

42. What happens in vit D excess
CG- 3 > AT-2 - More CG content - melting point goes up
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Silencers
Abnormal protein folding - degradation before reaching cell surface

43. Accurate base pairing is required only in the first two nucleotide positions of an mRNA codon - so conds differeing in the 3rd position may code for the same tRNA/AA due to degenerate genetic code
Comlex II
Wobble
B6
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss

44. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Lactate
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Epithelial cells

45. What substances induce phosphofructokinase
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Krabbes - galactocerebrosidase - galactocerebroside - AR
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
AMP - fructose 2 -6 BP

46. What are the results of CF on male fertility
Males are infertile due to bilateral absence of vas deferens
Tropoelastin with fibrillin scafolding
1 ring
Acetly- CoA - CO2 - NADH

47. Which enzyme involved in RNA synthesis does not require a template
VLDL
HDL
Poly A polymerase - signal is AAUAA
Colchicine

48. In what cell is collagen synthesis initiated
Ile - phe - thr - trp
Fibroblast
Wrinkles and acne
HMP shunt

49. How does cytosine become uracil
Inhibit DNA gyrase specific for prokaryotic topoisomerase
The triphosphate bond
Deamination
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia

50. congenital microdeletion of long arm of chromosoe 7 with findings of elfin facies - mental retardation - hypercalcemia - well developed verbal skills - extreme friendliness with strangers - cardiovascular problems
Rb and p53
Williams syndrome
Arg and his inc in histones Which bind negatively charged DNA
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year