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Biochemistry

Instructions:

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. nucleotide repeat for fragile x
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
CGG
CAG
Unwinds DNA template at replcation fork

2. Where do you find elastin and What does it do
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
PMNs
Reads usual codon but inserts wrong AA

3. Type IV collagen
Kwashiorkor - small child with swollen belly
Elastase - inhibited by alpha1 antitrypsin
Basement membrane or basal lamina
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side

4. What are the products for glycolysis
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Post to neg
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O

5. What are the symptoms of vit A excess
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
Flagella - cilia - mitotic spindles
Dec DNA - dec lymphos leads to SCID
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

6. Type I collagen
Malonyl coa
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Two
Disorder of aromatic amino acid metabolism

7. peripheral neuropathy - developmental delay - optic atrophy - glopoid cells
Krabbes - galactocerebrosidase - galactocerebroside - AR
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Oxalacetate
Hypoglycemia

8. What reaction does adenosine deaminase normally catalyze
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Silencers
Adenosine to inosine
Site of steroid synthesis and detoxification of drugs and poisons

9. What are the glucogenic/ketogenic amino acids
Ile - phe - thr - trp
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Rb and p53
Hypoglycemia

10. What is the TX for PKU
BOne
Zero
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Deamination

11. How many rings do purines have
Removes phosphate group from substrate
2 rings
Unwinds DNA template at replcation fork
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

12. What collagen type is most frequently affected in ehlers danlos and What are common complications
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Euchromatin
III - joint dislocation - anuerysms - organ rupture
SnRNPs and other proteins

13. What is NAD+ generally used for
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Catabolic processes to carry reducing equivalents away as NADH
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis

14. What do albinism - ARPKD - CF - glycogen storage diseases - hemochromatosis - mucopolysaccharidoses (except Hunters) PKU - sickle cell - sphingolipodoses (except Fabrys) thalassemias have in common
Neither of 2 alleles is dominant - blood groups
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Autosomal recessive diseases

15. energy malnutrition resulting in tissues and muscle wasting - loss of subQ fat - variable edema
Marasmus - muscle wasting
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
Karyotyping
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year

16. How do tetracyclines work
CG- 3 > AT-2 - More CG content - melting point goes up
Must be both activated and inactivated for cell cycle to progress
Seals.
Bind 30s subunit preventing attachment of aminoacyl - tRNA

17. How do aminoglycosides work
RRNA
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
By inhibiting formation of the initiation complex and cause misreading of mRNA

18. Which are the basic amino acids
IDL
Arg - lys - his - arg is most basic - has has no charge at body pH
CAG - 4
Same AA - often base change in 3rd position of codon (tRNA wobble)

19. congenital deficiency of homogentisic acid oxidase in the degradative pathway of tyrosine to fumarate leading to dark connective tissue - brown pigmented sclera - urine turns black on standing - dz and worst complication
2pq
VLDL
Alkaptonuria - may have debiliating arthralgias
Failure to track objects or develop a social smile

20. central and peripheral demyelination with ataxia and dementia
PFK - rate limiting enzyme
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Heterochromatin = HighlyCondensed

21. What enzyme degrades a small amount of glycogen in lysosomes
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
Result from phagocytic removal of heinz bodies my macs - G6PD def
Glutamate
Alpha 1 -4 glucosidase

22. Who typically has lactase def
Sulfation
African Americans and Asians
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
Targets the proteins for lysosome

23. What is a frame shift
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Dermatitis - glossitis - and diarrhea
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations

24. Why can't even chain fatty acids produce new glucose
They yield only acetyl - CoA equivalents
Proline and glycine (non glycosylated forms)
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis

25. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Four
Ketone - methyl
Intermediate filaments
Changed AA (convservative - new AA is similar in chemical structure)

26. What is the treatment for dec affinity of cystathionine synthase for pyroxidal phosphate
Inc vit B6
Mebendazole/thiabendazole
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin

27. What does inc phenylalanine lead to...
Phenylketones in urine
Alpha and beta tubulin - dimers have two GTP bound
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
HDL

28. What enzyme catalyzes the rxn from pyrvuate to Acetyl - CoA and what inhibits it
Protein kinase A
APRT + PRPP
B-100 - CII and E
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

29. What co - factors are required for the pyruvated dehydrogenase complex
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Specific glycosylases - AP endonuclease
Failure to track objects or develop a social smile
CAG - 4

30. What is the activated carrier for 1 carbon units
HMG- CoA (HMG- CoA to mevalonate
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
THFs
Antioxidant - protects RBCs and membrances from free radical damage

31. What happens in carnitine def
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Oligomycin
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Poly A polymerase - signal is AAUAA

32. What step begins the urea cycle and What is the enzyme needed - Where does it happen
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Poly A polymerase - signal is AAUAA
AR
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

33. What are the characteristics of angelmans syndrome and How does it occur
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
N to C
Change resulting in early stop codon
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele

34. How does OTC def present
Paclitaxel
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
Lysine and arginine
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

35. What amino acid makes up most of the octamer
Lysine and arginine
TRNA
Phenytoin - MTX - and sulfonamides
Inhibits lipoic acid - vomiting - rice water stools - garlic breath

36. What are the findings in Lesch - Nyhan
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Thymic - parathyroid and cardiac
Coenzyme A - lipoamide

37. Giving folate during early pregnancy is important to prevent what birth defects
Neural tube
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
Hyperlipidemia
Skin

38. What is the purpose of the HMP shunt
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
In ER - glucose 6- P to glucose
B12 and folate

39. What is variable expression and What is an example
Nature and severity of phenotype vary from 1 individual to another - NF type 1
PMNs
Citrate - acetyl coa from mito to cyto
Malabsorption and steatorrhea (ADEK)

40. How is vit D stored
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Accelearted muscle breakdown
25OHD3
Asp and Glu

41. Where is fructose 1 -6 bisphosphatase found and What does it do
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Ile - phe - thr - trp
Achondroplasia
RNA poly II

42. phosphorylation of glucose to yield glucose 6 phosphate serves as the 1st step of what rxns and what enzymes catalyze it
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Infection - free radicals generated by inflammatory response

43. Infection with what organism can cause B12 def
GAA
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Oxidative is irreversible
Diphyllobothrium latum

44. What causes maple syrup urine disease and What does it lead to...
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
NADH - NADPH - FADH2
Inhibits 50S peptidyltransferase
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL

45. What is the activated carrier for phosphoryl
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Creat a nick in the helix to relieave supercoils created during replication
FMR1 gene - methylation - associated with chromosomal breakage
ATP

46. What is the result of vit B5 def
Lactate
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
They yield only acetyl - CoA equivalents
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais

47. RNA poly can't proofread - but What can it do
Initiate chains
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Von gierkes - glucose 6 phosphatase
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision

48. What does NADPH oxidase deficiency result in and why
32 - malate aspartate shuttle
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Night blindness - dry skin
Acetly- CoA - CO2 - NADH

49. What initiates protein synthesis
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
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
30 - glycerol -3- phosphate shuttle

50. Severe fasting hypoglycemia - inc glycogen storage in liver - inc blood lactate - hepatomegaly - dz and def enzyme
GAA
N to C
Von gierkes - glucose 6 phosphatase
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects