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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 apolipoprotiens are on VLDL
Transfers methyl units
Tryptophan
B-100 - CII and E
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

2. In which single strand DNA repair mechanism do specific endonucleases release the oligonucTIDE containing bases and DNA poly and ligase fill and reseal - and what disease occures when this is mutated
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Mitochondria
Protective against malaria
Proton gradient

3. What is the function of Zinc
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Mucus secreting globlet cells and antibody secreting plasma cells
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1

4. What is the treatment for cystathionine synthase def
Dec methionine - inc cystiene - inc B12/folate
Failure to track objects or develop a social smile
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Inhibits 50S peptidyltransferase

5. What does universal genetic code refer to and What are some exception
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Phosphofructokinase 1

6. In eukaryotes - What does RNA poly I make
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
RRNA
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it
Transmitted only through mother - all offspring of affected females may show signs of disease

7. What is made fir rNucleotides or deoxyrNucleotides and what enzyme is necessary to convert one to the next
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Peroxide
Ribos first then deoxyribos with ribonucleotide reductase

8. Patients with chronic granulomatous disease are at increased risk of infection From which kind of organisms
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Cartilage - hyaline - vitreous body - nucleus pulposus
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

9. What does beta oxidation do and Where does it occur
Breaks down acyl - coa to acetyl coa groups in mito
Procollagen - triple helix of 3 alpha collagen chains
Males are infertile due to bilateral absence of vas deferens
Neurons

10. What are uncoupling agents
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
Stored ATP - creatine phosphate - anaerobic glycolysis
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

11. What is the results of vit B1 def
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
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
Mediates extra remnant take up
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible

12. What happens with wet beriberi
Procollagen - triple helix of 3 alpha collagen chains
High output cardiac failure - dilated cardiomyopathy - edema
X- linked recessive
AMP - fructose 2 -6 BP

13. Where is acetaldehyde located
Post to neg
Mitochondria
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Hypoglycemia

14. How is ammonium transported from muscle to the liver for urea cycle
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
Muscle
AR
Orotate precursor - with PRPP added later

15. In what cells do the respiratory burst occur
Metanephrine
PMNs
HMG- CoA reductase
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex

16. What is the energy source for tRNA actication (charging)
Chylomicrons
ATP
Consesus sequenec of base pairs
Carnitine acyltransferase I

17. What is NADPH used for
Same AA - often base change in 3rd position of codon (tRNA wobble)
Anabolic processes as a supply of reducing equivalents
Von hippel lindau - 3
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes

18. How is Lesch Neyhan inherited
B100
Binds to LDL receptor - mediates VLDL secretion
X- linked recessive
Lactate

19. What enzyme converts adenine to AMP
Dopa decarboxylase
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
APRT + PRPP

20. What does commaless - nonoverlapping genetic code refer to...
Read from a fixed starting point as a continuous sequence of bases
FISH
Von gierkes - glucose 6 phosphatase
Prevent strands from reannealing

21. What is axonemal dynein
Exercise: inc NAD/NADH - inc ADP - inc Ca
By inhibiting formation of the initiation complex and cause misreading of mRNA
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive

22. What does a decrease in decrease in NADPH lead to and why
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Carnitine acyltransferase I
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Mediates chylomicron secretion

23. characterize mitochondrial inheritance
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Transmitted only through mother - all offspring of affected females may show signs of disease
CG- 3 > AT-2 - More CG content - melting point goes up
B6

24. What enzyme converts glucose 1 p to UDP glucose
Assistance of upper extremities to stand up
UDP glucose pyrophosphorylase
RNA poly II
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

25. What happens in vit D def
Carnitine acyltransferase I
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Phenytoin - MTX - and sulfonamides
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)

26. What substances inhibit phosphofructokinase -1
ATP - citrate
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Base + ribose
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

27. What bone disorder has x linked dominant inheritance
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Cre - lox system
Arg and his inc in histones Which bind negatively charged DNA
MEN - 2A and 2B with ret gene

28. What is I cell disease
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Alkaptonuria - may have debiliating arthralgias

29. What kind of RNA is transported out of the nucleus
Only processed RNA
Metanephrine
Methionine encode by only 1 codon (AUG)
ATP hyrdolysis couple to energetically unfavorable rxns

30. What occurs to oxaloacetate in starvation and DKA
Adenosine to inosine
Histidine
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies

31. What does desmin stain for
Occurs when cells in the body have different genetic makeup - can be germline mosaic - which may produce a disease that is not carried by parents somatic cells - lyonization - random X inactivation in females
Muscle
Antioxidant - protects RBCs and membrances from free radical damage
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)

32. What is the TX for PKU
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
UGA - UAA and UAG
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet

33. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
RER
Robertsonian translocation and mosaicism
Skin
Nonsense > missense > silent

34. What happens in hyperammonemia
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Uses ATP to add high energy phophate group onto substrate

35. Give an example of a mitochondrial inherited disease
Inc glucagon - inc cAMP - inc PKA
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Stored ATP - creatine phosphate - anaerobic glycolysis

36. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
Neurofibromatosis type 1 (von Recklinghausens disease)
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
FAP
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

37. decreases In what substances can cause PKU
TRNA
HMG- CoA (HMG- CoA to mevalonate
Glucose 6 phosphate dehydrogenase (G6PD)
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor

38. What lab value can distinguish orotic aciduria from ornithine transcarbamoylase def?
G6PD
Acetly- CoA - CO2 - NADH
Glycine
OTC has hyperammonemia - orotic aciduira does not

39. What is variable expression and What is an example
High output cardiac failure - dilated cardiomyopathy - edema
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Peroxide
Alpha - ketoglutarate dehydrogenase complex

40. What is the defect in cystinuria
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
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
Inc insulin - dec cAMP - dec PKA
N to C

41. Is there any requirement for homology in NHEJ
VLDL
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
No - its non homologous
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells

42. What is the amino acid precuror for creatine - urea and nitric oxide
The triphosphate bond
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Arginine
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates

43. What are the fat soluble vitamins and What does their absorption depend on...
Glycogenolysis to form glucose
Grows slowly - collapses quickly
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations

44. What step of uric acid synthesis does xanthine oxidase catalyze
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
Hypoxanthine to xanthing and xanthine to uric acid
Tuberous sclerosis
Chylomicrons

45. What does a defective Cl channel do
25OHD3
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Malonyl coa
Secretion of abnl thick mucus that plugs lungs - pancreas - liver

46. What makes up a nucleoside
Wrinkles and acne
Diphyllobothrium latum
Four
Base + ribose

47. Type I bone
Breaks down acyl - coa to acetyl coa groups in mito
BOne
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
RNA

48. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Specific glycosylases - AP endonuclease
Locus heterogeneity - ocular albinism is x- linked recessive
Promotor - TATA box - and CAAT box - AT rich
Rb and p53

49. How many rings do pyrimidines have
1 ring
UGA - UAA and UAG
Polyneuritis - symmetrical muscle wasting
Citrate - acetyl coa from mito to cyto

50. Infection with what organism can cause B12 def
ATP hyrdolysis couple to energetically unfavorable rxns
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Diphyllobothrium latum