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. What is linkage disequilibrium
Oxidizes substrate
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Stored ATP - creatine phosphate - anaerobic glycolysis
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations

2. What is Gowers maneuver
Assistance of upper extremities to stand up
G6PD
TTP
Prokaryotic only - degrades RNA primer and fills in the gap with DNA

3. What does the start codon code for in eukaryotes and prokaryotes
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Eu - methionine - pro - formyl - methionine
Blood - bone marrown - amniotic fluid - placental tissue
Nature and severity of phenotype vary from 1 individual to another - NF type 1

4. characterize autosomal domint inheritance
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Disease
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Seals.

5. What is NADPH's role inside RBCs
Protein
Carnitine acyltransferase I
Keep glutathione reduced so it can detoxify free radicals and peroxides
Marfans

6. What is the TX for hyper ammonemia
DTMP
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Targets the proteins for lysosome
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels

7. 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
Methionine encode by only 1 codon (AUG)
Pseudomonas and s aureus
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Wobble

8. What does vit B3 def result in
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Griseofulvin
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Attachment of ubiquitin to defective proteins tag them for breakdown

9. What are purines made from
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
IMP precursor
Huntingtons
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

10. What substance accumulates in galactokinase def and What is the clinical picture
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Inc NADH/NAD ratio in liver - causing diversion of pyruvate to lactate and OAA to malate - inhibiting gluconeogenesis and stimulating fatty acid synthesis. Leads to hypoglycemia and hepatic fatty liver change seen in chronic EtOH users
9+2 arrangement of microtubules

11. When are glycogen reserves depleted
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
After day 1
32 - malate aspartate shuttle

12. What is the defectin IV - hypertriglyceridemia
Alpha 1 -4 glucosidase
Inhibits the Na/K pump by binding the K side
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Oxidative and nonoxidative - no ATP produced or used

13. What enzyme results in classic galactosemia and What is the clinical
Mediates chylomicron secretion
Schwann cells - lens - retina - kidneys
1 -25 OH2 D3 = calcitriol
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation

14. What is the defect in I- hyperchylomicronemia
UGA - UAA and UAG
Carnitine acyltransferase I
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
DTMP

15. What happens with dry beriberi
Lysine and leucine
Polyneuritis - symmetrical muscle wasting
SNP
Tyrosine

16. How do stable (quiescent) cells grow and regenerate and What are examples
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
X linked frame shif mutation
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

17. developmental delay - gargoylism - airway obstruction - corneal clouding - hepatosplenomegaly
Nine
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
SnRNPs
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

18. What rxn does propionyl - CoA carboxylase catalyze
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Disorder of aromatic amino acid metabolism
APRT + PRPP
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

19. What drugs can cause folate def
RNA
Phenytoin - MTX - and sulfonamides
Achondroplasia
DNA

20. What is used to diagnose muscular dystrophies
Phosphofructokinase 1
FISH
Inc CPK and muscle biopsy
Binds to LDL receptor - mediates VLDL secretion

21. Name 5 drugs that interfere with nucleotide synthesis
Free ribosomes
CTG
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Glycogen phosphorylase

22. What enzyme esterifies 2/3 of plasma cholesterol
Citrate - acetyl coa from mito to cyto
LCAT (lecithin cholesterol acyltransferase)
Breaks down acyl - coa to acetyl coa groups in mito
Neuralgia

23. What makes up a nucleotide

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

24. What apolipoproteins are on chylomicrons
Achondroplasia
B48 - AIV - CII - E
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Locus heterogeneity - ocular albinism is x- linked recessive

25. What does aminoacyl tRNA synthetase do the AA before and after it binds to tRNA - and what happens if it's the wrong the match
Scrutinizes - hydrolyzes the bond
Facial flushing
Accelearted muscle breakdown
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two

26. In addition to fructose and galactose - what sugards should be excluded from the diets of patients with disorders of fructose or galactose metabolism
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Adenosine to inosine
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Sucrose = glucose + fructose - lactose = glucose + galactose

27. What causes B12 def
Dec DNA - dec lymphos leads to SCID
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
B6
PCR - denaturation - annealing - elongation

28. What makes up a nucleoside
Ribos first then deoxyribos with ribonucleotide reductase
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
EtOH dehydrogenase and acetaldehyde dehydrogenase
Base + ribose

29. What is the amino acid precursor for histamine
CTG
Keep glutathione reduced so it can detoxify free radicals and peroxides
Histidine
Kidney - ears - eyes

30. 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

31. What are the fat soluble vitamins and What does their absorption depend on...
Abnormal protein folding - degradation before reaching cell surface
THFs
Williams syndrome
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity

32. What does PURe As Gold and CUT The Py stand for
Avidin
Purines= A - G pyrimidine = C - T (U)
Result from phagocytic removal of heinz bodies my macs - G6PD def
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

33. What causes maple syrup urine disease and What does it lead to...
Infection - free radicals generated by inflammatory response
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
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
MRNA

34. What is the physiologic role of dystrophin
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Protective against malaria
RRNA
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

35. How many ATP are produced by anearobic glycolysis per molecule of glucose
Neuralgia
They yield only acetyl - CoA equivalents
Two
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL

36. What are bite cells and when do you see them
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Schilling test
Result from phagocytic removal of heinz bodies my macs - G6PD def
Mcardle's - skeletal muscle glycogen posphorylase

37. How do labile celss grow and regenerate and What are examples
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Schwann cells - lens - retina - kidneys
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Liver hepatocytes and steroid producing cells of the adrenal cortex

38. Of the four possible fates for pyruvate - which one can replenish TCA cycle or be used in gluconeogenesis
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
HMG- CoA synthase
Fibrofatty replacement of muscle - cardiac myopathy
Oxalacetate

39. What trinucleotide repeat in Huntingtons and what chromosome is it found on...
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Euchromatin
CAG - 4
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US

40. What is the name is fxn of vit B3
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
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
Niacin - constituent of NAD and NADP - derived from tryptophan
AMP - fructose 2 -6 BP

41. What clotting factors require vit K
LDL
II - VII - IX - X (1972) protein C and S
Paclitaxel
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

42. Do balanced translocations cause abnl phenotype
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Phenylethamolamine N methyl transferase
No
They yield only acetyl - CoA equivalents

43. What does DNA poly III do?

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

44. What is codominance and give an example
Orotic acid to UMP
Neither of 2 alleles is dominant - blood groups
APRT + PRPP
Inc intestinal absorption fo calcium and phosphate - inc bone resorption

45. Milder form of type I with nl blood lactate levels - dz and enzyme

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

46. telangiectasia - recrrent epistaxis - skin discolorations - AVMs
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Conversion of NE to epi
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Attachment of ubiquitin to defective proteins tag them for breakdown

47. cytoskeletal elements in micorvilli - muscle contracting fibers - cytokenesis - adherens jxns
Actin and myosin
AR
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Tryptophan

48. What is disulfiram used for
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Epithelial cells
HMP shunt
Inc vit B6

49. Which phase of the HMP shunt is reversible and Which is irreversible
Adds an inorganic phosphate onto substrate without using ATP
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
Oxidative is irreversible
Glycine - aspartate - glutamine

50. What does the golgi assemble proteoglycans from
Oral uridine administration
High output cardiac failure - dilated cardiomyopathy - edema
Core proteins
Only processed RNA