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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 does amino acid catabolsim results in the formation of what?
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Histidine
Von Gierke's - Pompe - Cori - McArdle
Alpha - ketoglutarate dehydrogenase complex

2. What enzyme degrades a small amount of glycogen in lysosomes
Makes RNA primer on which DNA poly III can initiate replication
Polyneuritis - symmetrical muscle wasting
Grows slowly - collapses quickly
Alpha 1 -4 glucosidase

3. What 3 steps in RNA processing occur after transcription

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4. What is the longest time of RNA and shortest
Blood - bone marrown - amniotic fluid - placental tissue
Degradation of TG stored in adipocytes
MRNA - tRNA
Metanephrine

5. What does a kinase do
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
CAG - 4
Uses ATP to add high energy phophate group onto substrate
Glucose 6 phosphate dehydrogenase (G6PD)

6. What tissues have only aldose reductase
Schwann cells - lens - retina - kidneys
CG- 3 > AT-2 - More CG content - melting point goes up
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Leu - lys

7. What inhibits pyruvate kinase
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
SNP
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
ATP and alanine

8. What is the most common urea cycle disorder and What is the mode of inheritance?
Purines= A - G pyrimidine = C - T (U)
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Connective tissue

9. 90% of ADPKD cases are due to a mutation In what gene
APKD1 on chromosome 16
Ribose 5- P to PRPP
IDL
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

10. peripheral neuropathy - developmental delay - optic atrophy - glopoid cells
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
1/4 of offspring from 2 carrier parents are affected - often enzyme def - usually only seen in 1 generation - often more sever than AD - presents in childhood
Krabbes - galactocerebrosidase - galactocerebroside - AR
Lysine and arginine

11. What does cytokeratin stain for
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Epithelial cells
Cofactor for LPL

12. What is proteasomal degredation
Attachment of ubiquitin to defective proteins tag them for breakdown
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Deamination
25OHD3

13. What drugs can cause folate def
Marasmus - muscle wasting
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Phenytoin - MTX - and sulfonamides
Ile - phe - thr - trp

14. I g fat = ? Kcal
After day 1
Nine
Alkaptonuria - may have debiliating arthralgias
LCAT (lecithin cholesterol acyltransferase)

15. What does hartnups disease cause
Phenylketones in urine
GTP
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

16. What is axonemal dynein
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
GTP
LCAT (lecithin cholesterol acyltransferase)
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR

17. What makes up a nucleoside
P+q = 1
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Base + ribose
HVA

18. What co - factors are required for the pyruvated dehydrogenase complex
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
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Neither of 2 alleles is dominant - blood groups
DsRNA promotes degradation of target mRNA knocking down gene expression

19. What causes Down syndrome
Read from a fixed starting point as a continuous sequence of bases
Inhibits RNA polymerase II - found in death cap mushrooms
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

20. decreases In what substances can cause PKU
Basement membrane or basal lamina
THFs
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Antioxidant - facilitates iron absorption by keeping iron in the Fe2+ reduced state - necessary for hydroxylation of proline and lysine collagen bridges - necessary for dopamine beta hydroxylase which converts DA to NE

21. What clotting factors require vit K
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Paclitaxel
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
II - VII - IX - X (1972) protein C and S

22. What is the target of the 3' hydroxyl attack
ATP - citrate
30 - glycerol -3- phosphate shuttle
MEN - 2A and 2B with ret gene
The triphosphate bond

23. What creates the musty body odor in PKU
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Disorder of aromatic amino acid metabolism
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22

24. What is DNA cloning and How do you do it?
Cyclin dependent kinases;constitutive and inactive
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

25. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
9+2 arrangement of microtubules
Chylomicrons
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
Four

26. What is a nonsense mutation
Change resulting in early stop codon
Glutamine PRPP amidotransferase
Proline and glycine (non glycosylated forms)
Carbomoyl phosphate synthetase I

27. characterize mitochondrial inheritance
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Initiate chains
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Transmitted only through mother - all offspring of affected females may show signs of disease

28. What enzyme adds Cl - to the H202 to makes bleach
9+2 arrangement of microtubules
Myeloperoxidase
LCAT (lecithin cholesterol acyltransferase)
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis

29. What are the characteristics of prader willi syndrome How does it occur
Silencers
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
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

30. Which carbon bears the triphosphate and the energy source for bond formation

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31. What are the findings in PKU
Degredation of TG circulating in chylomicrons and VLDLs
Deamination
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Debranching enzyme

32. What two pathways is carbomoyl phosphate involved in - and what enzyme deficiency leads to a build of carbamoyl phosphate leading to what element in pyrimidine synthesis
GAA
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
Must be both activated and inactivated for cell cycle to progress
Anabolic processes as a supply of reducing equivalents

33. cell signaling defect of fibroblast growth factor (FGF) receptor 3 - results in dwarfism - short limbs - head/trunk nl size - associated with advanced paternal age
Achondroplasia
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Fibroblast
Mutated dystrophin gene - less severe - adolescence

34. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Malapsorption syndromes like sprue or CF or mineral oil intake
Each codon specifies only 1 amino acid
5' to 3'
HGPRT - defective purine salvage - excess uric acid production

35. Gene imprinting implies that How many alleles are active at a single locus
GAA
Cre - lox system
One
Supply sufficient glucose to brain and RBCs and to preserve protein

36. What is a silent mutation
Same AA - often base change in 3rd position of codon (tRNA wobble)
HMG- CoA synthase
Leu - lys
Phenylalanine hydroxylase

37. What is the most abundant protein in the body
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
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
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Collagen

38. How does ethanol induce hypoglycemia
B100
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
Adds 2 carbon with the help of biotin
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

39. What are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
African Americans and Asians
Cleft palate - cardiac abnl - pregs test
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
1 kind with multiple subunits

40. What is the TX for hyper ammonemia
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
Scrutinizes - hydrolyzes the bond
Makes RNA primer on which DNA poly III can initiate replication
Citrate - acetyl coa from mito to cyto

41. What are the products for glycolysis
Carnitine acyltransferase I
Disorder of aromatic amino acid metabolism
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15

42. What two rxns in in glycolysis require ATP
ATP
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

43. What converts NE to epi
Phenylethamolamine N methyl transferase
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
DsRNA promotes degradation of target mRNA knocking down gene expression
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible

44. What is maternal PKU
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Dec DNA - dec lymphos leads to SCID
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Mebendazole/thiabendazole

45. In which direction is protein synthesized
N to C
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
O- oligosaccharaides
PMNs

46. What is the limiting reagent in EtOH metabolism
NAD+
UGA - UAA and UAG
PFK - rate limiting enzyme
Malapsorption syndromes like sprue or CF or mineral oil intake

47. What does apoB100 do
Huntingtons
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
Binds to LDL receptor - mediates VLDL secretion
Dermatitis - enteritis - alopecia - adrenal insuff

48. What residues are hydroxylated in step 2 of collagen synthesis - and What does this require
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Proline and lysine - vit C
Arginine
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

49. What tissue samples are used for karyotyping
Accelearted muscle breakdown
Result from phagocytic removal of heinz bodies my macs - G6PD def
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Blood - bone marrown - amniotic fluid - placental tissue

50. What is the origin of replication
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Phosphorylation - glycosylation - hydroxylation
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Particular sequence of DNA where replicatino begins - may be single of multiple