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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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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. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Alanine
MRNA
CG- 3 > AT-2 - More CG content - melting point goes up
ATP - citrate

2. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
SnRNPs
P+q = 1
Disease
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes

3. What is the defect in II A familial hypercholesterolemia
3' end (with CCA)
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
DTMP
Marasmus - muscle wasting

4. What converts DOPA to dopamine
No - its non homologous
Dopa decarboxylase
40 - 60 - 80
Disorder of aromatic amino acid metabolism

5. What do the single stranded binding proteins do
O- oligosaccharaides
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
Thymic - parathyroid and cardiac
Prevent strands from reannealing

6. What does biotin def cause
Acetyl - CoA to malonyl - CoA (2C to 3C)
Dermatitis - alopecia - enteritis
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Miscarriage - stillbirth - chromosomal imbalance (down - patau)

7. Where are FADH2 electrons transferred to...
75 to 90 - cloverleaf
Tuberous sclerosis
Comlex II
Neg to pos

8. Name 5 drugs that interfere with nucleotide synthesis
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
LCAT (lecithin cholesterol acyltransferase)
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Tryptophan

9. What does amino acid catabolsim results in the formation of what?
MEN - 2A and 2B with ret gene
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Alanine
Q -

10. How do odd chain fatty acids participate in gluconeogenesis
RER
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Phosphorylation - glycosylation - hydroxylation

11. Infection with what organism can cause B12 def
Adds 2 carbon with the help of biotin
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Diphyllobothrium latum
Isocitrate dehydrogenase

12. In prokaryotes - What does makes the different types of RNA
Cyclin dependent kinases;constitutive and inactive
Isocitrate dehydrogenase
1 kind with multiple subunits
HVA

13. Fluorescent DNA or RNA probe binds to specific gene of interest - used for specific localization of genes and direct visualization of anomalies - like microdeletions - at molecular level
Neg to pos
FISH
NAD+
Inc melt - dec fluidity

14. What test is used for B12 def
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Schilling test
Unmethylated - newly synthesized - HNPCC

15. How do cardia glycosides work
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Deamination
Locus heterogeneity - ocular albinism is x- linked recessive
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

16. Where do you find elastin and What does it do
Inc CPK and muscle biopsy
By inhibiting formation of the initiation complex and cause misreading of mRNA
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
2pq

17. What is incomplete penetrence and give an example
AMP - fructose 2 -6 BP
Not all individuals with a mutant genotype show the mutant phenotype
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Krabbes - galactocerebrosidase - galactocerebroside - AR

18. Which phase of the HMP shunt is reversible and Which is irreversible
Inhibits RNA polymerase II - found in death cap mushrooms
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Pyruvate to oxaloacetate (3C to 4C)
Oxidative is irreversible

19. What are the results of unbalanced translocation
Tyrosine
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Miscarriage - stillbirth - chromosomal imbalance (down - patau)

20. What does the golgi add to serine and threonine residues
O- oligosaccharaides
Lacks glucose 6 phophatase
Inc vit B6
3' end (with CCA)

21. What does an umabiguous genetic code refer to...
Each codon specifies only 1 amino acid
Ketone - methyl
Phosphorylation - glycosylation - hydroxylation
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis

22. What happens in folate def
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Acetly- CoA - CO2 - NADH
Semiconservative - continuous and discontinuous strands (okazaki fragments)
DsRNA promotes degradation of target mRNA knocking down gene expression

23. benign asymptomatic condition with elevated levels of fructose in urine and blood - dz and enzyme
Essential fructosuria - fructokinase AR
Result from phagocytic removal of heinz bodies my macs - G6PD def
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Biotin

24. What is Retin A used topically for
Wrinkles and acne
Cre - lox system
Nine
Peroxide

25. What is the exception to genetic redundancy
Von Gierke's - Pompe - Cori - McArdle
Methionine encode by only 1 codon (AUG)
Glycolysis and aerobic respiration
Acetyl - CoA carboxylase (ACC)

26. Why can't even chain fatty acids produce new glucose
They yield only acetyl - CoA equivalents
Terminal regions - tropocollagen
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

27. Which cells are rich in smooth ER
Fed
Liver hepatocytes and steroid producing cells of the adrenal cortex
Lysine and arginine
Free ribosomes

28. What happens on the oxidative arm of the HMP shunt and What is the key enzyme
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
III - joint dislocation - anuerysms - organ rupture
Alanine

29. What order kinetics does EtOH dehydrogenase have
In ER - glucose 6- P to glucose
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Zero
75 to 90 - cloverleaf

30. hepatosplenomegaly - aseptic necrosis of femur - bone crisis - MACS that look like crumpled tissue paper

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31. What enzyme converts phenylalanine to tyrosin
Phenylalanine hydroxylase
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
NADPH
Attachment of ubiquitin to defective proteins tag them for breakdown

32. ADPKD is associated with What additional conditions
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Familial hypercholesterolemia - hyperlipidemia type IIA
Abnormal protein folding - degradation before reaching cell surface

33. I g fat = ? Kcal
Proline and lysine - vit C
Inc vit B6
Nine
Particular sequence of DNA where replicatino begins - may be single of multiple

34. What is the hardy weinber heterozygote prevalence
2pq
Modifies N- oligosaccharides
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)

35. nucleotide repeat for fredreich's ataxia
Infection - free radicals generated by inflammatory response
Polycystic liver disease - berry aneurysm - mitral valve prolapse
GAA
Must be both activated and inactivated for cell cycle to progress

36. How doe NADH electrons from glycolysis and the TCA cycle enter the mitochondiria
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
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
NAD+
CTG

37. How do tetracyclines work
Dec DNA - dec lymphos leads to SCID
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
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Fed

38. Type III collagen
Essential fructosuria - fructokinase AR
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
HVA
Lysine and arginine

39. Which aspect of the spliceosome do patients with lupus make antibodies against
IDL
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
SnRNPs

40. nucleotide repeat for fragile x
In ER - glucose 6- P to glucose
CGG
HMP shunt
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

41. several distinct syndromes characterized by familial tumors of endocrine glands including pancreas - parathyroid - pituitary - thryoid and adrenal medulla - disorders and gene association
Each codon specifies only 1 amino acid
Heterochromatin = HighlyCondensed
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
MEN - 2A and 2B with ret gene

42. Type II collagen
Cartilage - hyaline - vitreous body - nucleus pulposus
Fasting
ATP
Hepatic glycogenolysis - adipose tissue release of FFA - muslce and liver FFA - hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and proprionyl - coA (odd chain FFA)

43. What is the energy source after day 3 of starvation
B100 and E
Alpha 1 -4 glucosidase
HMG- CoA (HMG- CoA to mevalonate
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

44. What does a dehydrogenase do
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Oxidizes substrate
Scrutinizes - hydrolyzes the bond
Alcohol version of glucose - can trap glucose in cell - aldose reductase

45. What is the function of folic acid
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Type II
HMG- CoA synthase

46. Type IV collagen is an important structural componenet of the BM for which 3 organs
Kidney - ears - eyes
Glucose -6 phosphate
Catabolic processes to carry reducing equivalents away as NADH
Kwashiorkor - small child with swollen belly

47. Which direction does kinesin go
Achondroplasia
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Neg to pos
Biotin

48. What is variable expression and What is an example
RRNA
Glucose 6 phosphate dehydrogenase (G6PD)
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Facial flushing

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

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50. What is the activated carrier for phosphoryl
ATP
2 rings
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
FAP