Test your basic knowledge |

Biochemistry

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Which step in the de novo purine and pyrimidine synthesis pathway requires aspartate - glycine - glutamine and THF
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Palate - facial and cardiac defects
Targets the proteins for lysosome
Ribose 5- P to PRPP

2. What are the two possible causes of albinism
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
HMG- CoA reductase
OTC has hyperammonemia - orotic aciduira does not

3. What is the treatment for cystathionine synthase def
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
B6
Von hippel lindau - 3
Dec methionine - inc cystiene - inc B12/folate

4. What are the irreversible enzymes of gluconeogenesis
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
One

5. What enzyme turns ROS to H2O2
Superoxide dismutase
Anabolic processes as a supply of reducing equivalents
Liver - ovaries - seminal vesicles
Lysine and arginine

6. Type IV collagen is an important structural componenet of the BM for which 3 organs
Inhibits 50S peptidyltransferase
The triphosphate bond
Kidney - ears - eyes
Arg and his inc in histones Which bind negatively charged DNA

7. Giving folate during early pregnancy is important to prevent what birth defects
Neural tube
B100 and E
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase

8. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
Sulfation
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Cri du chat
Antibiotic use or excessive ingestion of raw eggs

9. telangiectasia - recrrent epistaxis - skin discolorations - AVMs
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
MRNA
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination

10. what disease can cause pellagra
MEN - 2A and 2B with ret gene
B6
Colchicine
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)

11. What substance inside the cell reduces glutatione
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Colchicine
NADPH
Flank pain - hematuria - HTN - progressive renal failure

12. What is the target of the 3' hydroxyl attack
The triphosphate bond
CG- 3 > AT-2 - More CG content - melting point goes up
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Transmitted only through mother - all offspring of affected females may show signs of disease

13. pyruvate carboxylase catalyzes what rxn
HGPRT - defective purine salvage - excess uric acid production
Pyruvate to oxaloacetate (3C to 4C)
Inc dicarboxylic acids - dec in glucose and ketones
Oral uridine administration

14. What is the most common urea cycle disorder and What is the mode of inheritance?
Glycolysis and aerobic respiration
AR
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
ATP

15. What is DNA cloning and How do you do it?
2pq
B48 - AIV - CII - E
Diphyllobothrium latum
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

16. Which cells are rich in smooth ER
CAG - 4
Malabsorption and steatorrhea (ADEK)
Liver hepatocytes and steroid producing cells of the adrenal cortex
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

17. What defects characterize velocardiofacial syndrome
Ribose 5- P to PRPP
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
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Palate - facial and cardiac defects

18. What does commaless - nonoverlapping genetic code refer to...
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Site of steroid synthesis and detoxification of drugs and poisons
Read from a fixed starting point as a continuous sequence of bases
HVA

19. What is the defectin IV - hypertriglyceridemia
Colchicine
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Neurons
Core proteins

20. cell signaling defect of fibroblast growth factor (FGF) receptor 3 - results in dwarfism - short limbs - head/trunk nl size - associated with advanced paternal age
AMP - fructose 2 -6 BP
Achondroplasia
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Specific glycosylases - AP endonuclease

21. In eukaryotes - What does RNA poly III make
TRNA
Must be both activated and inactivated for cell cycle to progress
40 - 60 - 80
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

22. What causes Marfan syndrome
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Defect in fibrillin
Proton gradient
Neural tube

23. What 3 steps in RNA processing occur after transcription

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

24. Where is acetaldehyde located
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
IDL
Von hippel lindau - 3
Mitochondria

25. What substances are uncouling agents
More than 1 codon may code for the same amino acid
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
2 -4 DNP - aspirin

26. What are the complications/signs of familial hypercholesterolemia
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Adds an inorganic phosphate onto substrate without using ATP
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact

27. What step begins the urea cycle and What is the enzyme needed - Where does it happen
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Abnormal protein folding - degradation before reaching cell surface
AMP - fructose 2 -6 BP

28. What is regeneration of methionine depedent on...
Catabolic processes to carry reducing equivalents away as NADH
B12 and folate
Inhibits RNA polymerase II - found in death cap mushrooms
Neuralgia

29. How is orotic aciduria inherited
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
ATP
AR
PMNs

30. Describe the structure of cilia
Histidine
1 kind with multiple subunits
9+2 arrangement of microtubules
Oligomycin

31. Is there any requirement for homology in NHEJ
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
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
No - its non homologous

32. What are the only purely ketogenic amino acids
OTC has hyperammonemia - orotic aciduira does not
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Lysine and leucine

33. What does hartnups disease cause
More than 1 codon may code for the same amino acid
Glucose - 2Pi - 2ADP - 2NAD+
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Huntingtons

34. What is the Name and fxn of vit B5
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
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase

35. What do the single stranded binding proteins do
BOne
Prevent strands from reannealing
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Proline and lysine - vit C

36. What is the complication of cystinuria
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
5' of the incoming nucleotide
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Adds 2 carbon with the help of biotin

37. What does cytokeratin stain for
Carbomoyl phosphate synthetase II
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Epithelial cells
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

38. What apolipoprotiens are on VLDL
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
Each codon specifies only 1 amino acid
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
B-100 - CII and E

39. What is Gowers maneuver
Degradation of TG remaining in IDL
UGA - UAA and UAG
II - VII - IX - X (1972) protein C and S
Assistance of upper extremities to stand up

40. Infection with what organism can cause B12 def
Fed
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Diphyllobothrium latum

41. What causes Down syndrome
3' end (with CCA)
2 rings
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
IDL

42. What are uncoupling agents
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
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
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
UGA - UAA and UAG

43. What are the findings in Lesch - Nyhan
B12 and folate
Actin and myosin
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis

44. What happens do glycogen in skeletal muscle during exercise
Glycogenolysis to form glucose
Chylomicrons
Mebendazole/thiabendazole
AMP - fructose 2 -6 BP

45. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
No
SAM
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

46. What is uniparental disomy
Familial hypercholesterolemia - hyperlipidemia type IIA
Core proteins
African Americans and Asians
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent

47. What is the activated carrier for phosphoryl
ATP
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease

48. What is loss of heterozygosity and give an example
Lysine and arginine
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
NF2 on chromosome 22
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

49. What reaction does adenosine deaminase normally catalyze
MRNA - tRNA
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Coenzyme A - lipoamide
Adenosine to inosine

50. What happens in zinc def
Catabolic processes to carry reducing equivalents away as NADH
LDL
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis