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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. depression - progressive dementia - choreiform movements - caudate atrophy and dec levels of GABA and ACH in the brain
Huntingtons
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Von hippel lindau - 3
Mebendazole/thiabendazole

2. What are the water soluble vitamins - which ones are stored
CTG
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Core proteins

3. What drugs can cause folate def
CAG - 4
Met - val - arg his
Hypoxanthine to xanthing and xanthine to uric acid
Phenytoin - MTX - and sulfonamides

4. What are the physical findings of fragile x syndrome
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Grows slowly - collapses quickly
AMP - fructose 2 -6 BP

5. What happens on the oxidative arm of the HMP shunt and What is the key enzyme
Glucose 6 phosphate dehydrogenase (G6PD)
Actin and myosin
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
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

6. What are the findings in Down's syndrome
Mental retardation - flat facies - prominent epicanthal folds - simian crease - gap between 1st 2 toes - duodenal atresia - congenital heart disease (ASD) - inc risk of All and Alzheimers
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
Ca/calmodulin in muscle to coordinate with muscle activity
1 ring

7. What tissue samples are used for karyotyping
Blood - bone marrown - amniotic fluid - placental tissue
Achondroplasia
NADH - NADPH - FADH2
II - VII - IX - X (1972) protein C and S

8. What is the most abundant protein in the body
Hypoglycemia
Collagen
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
FMR1 gene - methylation - associated with chromosomal breakage

9. What substance accumulates in galactokinase def and What is the clinical picture
Inhibits 50S peptidyltransferase
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Neg to pos
Essential fructosuria - fructokinase AR

10. What enzyme turns ROS to H2O2
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Grows slowly - collapses quickly
Attachment of ubiquitin to defective proteins tag them for breakdown
Superoxide dismutase

11. What is anticipation and give an example
Orotate precursor - with PRPP added later
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
DsRNA promotes degradation of target mRNA knocking down gene expression

12. trinucleotide repeat fo myotonic dystrophy
CTG
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Glutamine PRPP amidotransferase
ATP - citrate

13. Type IV BM
Uses ATP to add high energy phophate group onto substrate
4 under the floor
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
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

14. What test is used for B12 def
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
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Schilling test
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea

15. What are the results of unbalanced translocation
Transfers methyl units
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
LDL
Miscarriage - stillbirth - chromosomal imbalance (down - patau)

16. What does hartnups disease cause
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Muscle
Scrutinizes - hydrolyzes the bond

17. What is the Hardy Weinberg disease prevalence equation
Schilling test
P2 +2pq+ = 1
Mebendazole/thiabendazole
Prevent strands from reannealing

18. progressive neurodegeneration - developmental delay - cherry red spot on macula - lysosomes with onion skin - NO hepatosplenomegaly
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
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
ATP
Antibiotic use or excessive ingestion of raw eggs

19. Pts with albinism are at inc risk For what cancer
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Proton gradient
Skin
Malabsorption and steatorrhea (ADEK)

20. What is the longest time of RNA and shortest
MRNA - tRNA
Night blindness - dry skin
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Alpha1 antitrypsin

21. What lab technique is use to profile gene expression levels of thousands of genes simultaneously to study certain diseases and treatments
Liver hepatocytes and steroid producing cells of the adrenal cortex
Microarrays
Karyotyping
Nature and severity of phenotype vary from 1 individual to another - NF type 1

22. What are the irreversible enzymes of gluconeogenesis
G6PD
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Oxalacetate

23. Why does alpha amanitin cause liver failure and Where is it found
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
GTP
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Inhibits RNA polymerase II - found in death cap mushrooms

24. In which direction is protein synthesized
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
N to C
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes

25. Why is G6PD def more common among patients of african decent
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Protective against malaria

26. NADPH are used In what 4 things
B-100 - CII and E
LDL
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Oligomycin

27. What is the wernicke - korsakoff clinical picture
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Euchromatin
The triphosphate bond

28. What happens to glycogen in the liver
Creat a nick in the helix to relieave supercoils created during replication
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Peroxide

29. What enzyme does fructose metabolism bypass to reach glycolysis
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
PFK - rate limiting enzyme

30. What is the structure of elastin
Tropoelastin with fibrillin scafolding
Base + ribose
Sulfation
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)

31. Why is albinism inheritnace varialbe due to...
RNA
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Locus heterogeneity - ocular albinism is x- linked recessive
Alpha and beta tubulin - dimers have two GTP bound

32. What is the TX for PKU
Ribos first then deoxyribos with ribonucleotide reductase
Facial flushing
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Coenzyme A - lipoamide

33. What is the pathway in the fasting state leading to inc FBPase -2 and dec PFK-2
Inc glucagon - inc cAMP - inc PKA
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Neurons
Coenzyme A - lipoamide

34. How does warfarin work
Rb and p53
Vit K antagonist
MRNA
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

35. In eukaryotes - What does RNA poly III make
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
TRNA
Infection - free radicals generated by inflammatory response
Supply sufficient glucose to brain and RBCs and to preserve protein

36. What is made fir rNucleotides or deoxyrNucleotides and what enzyme is necessary to convert one to the next
Ribos first then deoxyribos with ribonucleotide reductase
Basement membrane or basal lamina
Mental retardation - flat facies - prominent epicanthal folds - simian crease - gap between 1st 2 toes - duodenal atresia - congenital heart disease (ASD) - inc risk of All and Alzheimers
NF2 on chromosome 22

37. Where are FADH2 electrons transferred to...
Pyruvate to oxaloacetate (3C to 4C)
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Comlex II
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)

38. What is the limiting reagent in EtOH metabolism
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Assistance of upper extremities to stand up
CAG - 4
NAD+

39. What does commaless - nonoverlapping genetic code refer to...
Grows slowly - collapses quickly
Alpha - ketoglutarate dehydrogenase complex
Read from a fixed starting point as a continuous sequence of bases
P+q = 1

40. What two proteins make up microtubules and how are they arranged
Antibiotic use or excessive ingestion of raw eggs
Alpha and beta tubulin - dimers have two GTP bound
Glycogenolysis to form glucose
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver

41. What are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
Rotenone - CN- - antimycin A - CO
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Cleft palate - cardiac abnl - pregs test
Reads usual codon but inserts wrong AA

42. What are the fetal screening measures for Down
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Robertsonian translocation and mosaicism
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation

43. What do the single stranded binding proteins do
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Result from phagocytic removal of heinz bodies my macs - G6PD def
Epithelial cells
Prevent strands from reannealing

44. What collagen type is most frequently affected in ehlers danlos and What are common complications
5' to 3'
III - joint dislocation - anuerysms - organ rupture
Fasting
Oxidized hemoglobin precipiated within RBCs

45. What shuttle is involved in fatty acid synthesis and What does it move From where to where
Citrate - acetyl coa from mito to cyto
Liver hepatocytes and steroid producing cells of the adrenal cortex
Dermatitis - glossitis - and diarrhea
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

46. Severe fasting hypoglycemia - inc glycogen storage in liver - inc blood lactate - hepatomegaly - dz and def enzyme
Von gierkes - glucose 6 phosphatase
CTG
Stop codon is recognized by release factor - and completed protein is released from ribosome
Comlex II

47. What is dominant negative mutation and give an example
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding

48. benign asymptomatic condition with elevated levels of fructose in urine and blood - dz and enzyme
Connective tissue
Two
Essential fructosuria - fructokinase AR
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy

49. What does CATCH 22 stand for and What causes is...
Inhibits 50S peptidyltransferase
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Glycogen phosphorylase
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

50. What substance in egg whites binds biotin
HMG- CoA reductase
Avidin
Eu - methionine - pro - formyl - methionine
Failure to track objects or develop a social smile