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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 is the breakdown product of epi
Metanephrine
GAA
Alpha - ketoglutarate dehydrogenase complex
MRNA

2. What is I cell disease
Tryosine hydroxylase
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Biotin
Breaks down acyl - coa to acetyl coa groups in mito

3. In eukaryotes - What does RNA poly I make
Tuberous sclerosis
RRNA
Four
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

4. What does a phosphorylase do
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
Adds an inorganic phosphate onto substrate without using ATP
Arginine
Inc dicarboxylic acids - dec in glucose and ketones

5. What tissues have only aldose reductase
Tropoelastin with fibrillin scafolding
III - joint dislocation - anuerysms - organ rupture
Schwann cells - lens - retina - kidneys
Deamination

6. What substance inside the cells replenishes NADPH
G6PD
ATP
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
LDL

7. Is there any requirement for homology in NHEJ
Stored ATP - creatine phosphate - anaerobic glycolysis
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
No - its non homologous
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate

8. What substances inhibit phosphofructokinase -1
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
B100
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
ATP - citrate

9. Inhibition of thymidilate synthase and and DHFR lead to decrease In what substance
Orotate precursor - with PRPP added later
DTMP
No
B100 and E

10. Which enzyme involved in RNA synthesis does not require a template
Inc melt - dec fluidity
Lysine and arginine
Cleft palate - cardiac abnl - pregs test
Poly A polymerase - signal is AAUAA

11. Where is hexokinase found - What is its Km and Vmax and what uninduces it
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Initiate chains
75 to 90 - cloverleaf
B100

12. What happens in hyperammonemia
Pyruvate to oxaloacetate (3C to 4C)
Muscle
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision

13. What are covalent alterations
II - VII - IX - X (1972) protein C and S
Liver - ovaries - seminal vesicles
CAG
Phosphorylation - glycosylation - hydroxylation

14. What polar group does guanine have - and what non polar group does thymine have
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Type II
Ketone - methyl
Adds 2 carbon with the help of biotin

15. What rxn does propionyl - CoA carboxylase catalyze
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Breaks down acyl - coa to acetyl coa groups in mito
9+2 arrangement of microtubules

16. How is Lesch Neyhan inherited
Inc CPK and muscle biopsy
X- linked recessive
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

17. What part of the pre mRNA contains the actual genetic information coding for protein
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Elastase - inhibited by alpha1 antitrypsin
Paclitaxel
Exons

18. What are bite cells and when do you see them
Result from phagocytic removal of heinz bodies my macs - G6PD def
Elastase - inhibited by alpha1 antitrypsin
Tropoelastin with fibrillin scafolding
Defect in fibrillin

19. How does chloramphenicol work
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Promotor - TATA box - and CAAT box - AT rich
Removal of N or C termal propeptides from zymogens to generate mature proteins
Inhibits 50S peptidyltransferase

20. FAP is due to deletion On what gene On what chromosome
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Creat a nick in the helix to relieave supercoils created during replication
APC on chromosome 5
MEN - 2A and 2B with ret gene

21. What is codominance and give an example
Inc Cl - in sweat
Neither of 2 alleles is dominant - blood groups
Bruton's agammaglobulinemia - wiskott - aldrich - fabrys disease - G6PD def - ocular albinism - Lesch - Nyhan syndrome - Duchenne and Becker Muscular Dystrophy - hunter's syndrome - hemophilia A and B
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS

22. I g fat = ? Kcal
Orotate precursor - with PRPP added later
Nine
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Prokaryotic only - degrades RNA primer and fills in the gap with DNA

23. What does fomepizole do
Poly A polymerase - signal is AAUAA
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Cri du chat

24. In mismatch repair - which strand is recognized and In what hereditary syndrome is this defective
Failure to track objects or develop a social smile
Unmethylated - newly synthesized - HNPCC
Ribos first then deoxyribos with ribonucleotide reductase
B-100 - CII and E

25. What is the defect in fructose intolerance and What does it cause
1 kind with multiple subunits
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Supply sufficient glucose to brain and RBCs and to preserve protein
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

26. What tissue samples are used for karyotyping
PFK - rate limiting enzyme
HMG- CoA (HMG- CoA to mevalonate
Elastase - inhibited by alpha1 antitrypsin
Blood - bone marrown - amniotic fluid - placental tissue

27. Why is albinism inheritnace varialbe due to...
Initiate chains
Locus heterogeneity - ocular albinism is x- linked recessive
Hereditary spherocytosis
Acetyl - CoA to malonyl - CoA (2C to 3C)

28. What are CDKs
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Rotenone - CN- - antimycin A - CO
Elastase - inhibited by alpha1 antitrypsin
Cyclin dependent kinases;constitutive and inactive

29. What does DNA poly I do?
Biotin
Unwinds DNA template at replcation fork
Intermediate filaments
Prokaryotic only - degrades RNA primer and fills in the gap with DNA

30. What do def in in enzymes of gluconeogenesis cause
Not all individuals with a mutant genotype show the mutant phenotype
Lacks glucose 6 phophatase
Hypoglycemia
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles

31. What is the structure of elastin
Tropoelastin with fibrillin scafolding
Cre - lox system
Dopa decarboxylase
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

32. What apolipoprotein is on LDL
Huntingtons
ATP
B100
Glucose -6 phosphate

33. What causes biotin def
Antibiotic use or excessive ingestion of raw eggs
After day 1
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
Dopamine beta hydroxylase

34. What is the fxn of vit D
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Inc Cl - in sweat
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Foliage - small reserve in liver - eat green leaves

35. What are the priorities for the body in fasting and starvation
Supply sufficient glucose to brain and RBCs and to preserve protein
Ketone - methyl
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

36. What substance accumulates in galactokinase def and What is the clinical picture
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
P+q = 1
ATP hyrdolysis couple to energetically unfavorable rxns

37. spheroid RBCs due to spectrin or ankyrin defect - hemolytic anemia - inc MHCH - splenectomy is curative
RRNA
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Hereditary spherocytosis

38. Mild Hurlurs + aggressive behavior no corneal clouding
Oxidative is irreversible
X- linked recessive
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR

39. What does a kinase do
Marfans
Uses ATP to add high energy phophate group onto substrate
Assistance of upper extremities to stand up
Mebendazole/thiabendazole

40. What drugs can cause folate def
Phenytoin - MTX - and sulfonamides
SnRNPs and other proteins
After day 1
VLDL

41. What happens in termination of proteins synthesis
Stop codon is recognized by release factor - and completed protein is released from ribosome
Phosphofructokinase 1
ATP
Cartilage - hyaline - vitreous body - nucleus pulposus

42. What is variable expression and What is an example
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Nature and severity of phenotype vary from 1 individual to another - NF type 1
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
Lysine and arginine

43. What is the function of folic acid
Inhibit DNA gyrase specific for prokaryotic topoisomerase
Nissl body - enzyme and NTs
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle

44. Gene imprinting implies that How many alleles are active at a single locus
Locus heterogeneity - ocular albinism is x- linked recessive
RER
Inc melt - dec fluidity
One

45. How do labile celss grow and regenerate and What are examples
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
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
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles

46. What are uncoupling agents
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
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
Liver - ovaries - seminal vesicles
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin

47. How do you diagnose CFTR
Oral uridine administration
Inc Cl - in sweat
Inc vit B6
Acetyl - CoA

48. How many nucTIDEs is a tRNA and What does the secondary sturcture form
75 to 90 - cloverleaf
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Von gierkes - glucose 6 phosphatase
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

49. What is Retin A used topically for
Mebendazole/thiabendazole
Wrinkles and acne
32 - malate aspartate shuttle
Must be both activated and inactivated for cell cycle to progress

50. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Makes RNA primer on which DNA poly III can initiate replication
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
AR