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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. What is the function of biotin
Skin
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
High output cardiac failure - dilated cardiomyopathy - edema

2. trinucleotide repeat fo myotonic dystrophy
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
CTG
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP

3. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
Paclitaxel
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Rb and p53
Vit K antagonist

4. What does the CFTR channel do in the lungs - GI tract and skin
RRNA
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Active secretion in lungs and GI - reabsorbs in skin
Sucrose = glucose + fructose - lactose = glucose + galactose

5. What two proteins make up microtubules and how are they arranged
Neuralgia
Alpha and beta tubulin - dimers have two GTP bound
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Unwinds DNA template at replcation fork

6. In base excision repaire - what recognizes and removes damaged bases and what cuts the DNA to remove the empty sugar
EtOH dehydrogenase and acetaldehyde dehydrogenase
Specific glycosylases - AP endonuclease
Vit K antagonist
Cartilage - hyaline - vitreous body - nucleus pulposus

7. What is RNAi used for
Peroxide
Malapsorption syndromes like sprue or CF or mineral oil intake
Tryptophan
DsRNA promotes degradation of target mRNA knocking down gene expression

8. what disease can cause pellagra
PFK - rate limiting enzyme
Stored ATP - creatine phosphate - anaerobic glycolysis
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Paclitaxel

9. What is the TX for PKU
Mcardle's - skeletal muscle glycogen posphorylase
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR

10. What creates the musty body odor in PKU
Disorder of aromatic amino acid metabolism
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
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Palate - facial and cardiac defects

11. What is the fxn of vit E
Antioxidant - protects RBCs and membrances from free radical damage
II - VII - IX - X (1972) protein C and S
Initiate chains
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

12. What causes Marfan syndrome
Defect in fibrillin
NADH - NADPH - FADH2
Glycolysis and aerobic respiration
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

13. What does desmin stain for
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Muscle
4 under the floor
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

14. Which step in the de novo purine and pyrimidine synthesis pathway requires just aspartate
Orotic acid to UMP
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
NADH - NADPH - FADH2
Antibiotic use or excessive ingestion of raw eggs

15. what findings are associated with marfans
Basement membrane or basal lamina
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Muscle

16. Type II cartilage
Ketone - methyl
F16BP
CarTWOlage
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step

17. What is the longest time of RNA and shortest
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Dermatitis - enteritis - alopecia - adrenal insuff
MRNA - tRNA
Alpha 1 -4 glucosidase

18. What are the fat soluble vitamins and What does their absorption depend on...
Neurons
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Carbomoyl phosphate synthetase I
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies

19. What is NAD+ generally used for
Catabolic processes to carry reducing equivalents away as NADH
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
2pq
BOne

20. Which end of the tRNA is the amino acid bound to...

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21. What initiates protein synthesis
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Von gierkes - glucose 6 phosphatase

22. What shuttle is involved in fatty acid synthesis and What does it move From where to where
Locus heterogeneity - ocular albinism is x- linked recessive
Citrate - acetyl coa from mito to cyto
Biotin
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.

23. What is the Name and function of vit B2
Actin and myosin
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Polycystic liver disease - berry aneurysm - mitral valve prolapse

24. How do tetracyclines work
Particular sequence of DNA where replicatino begins - may be single of multiple
5' of the incoming nucleotide
Bind 30s subunit preventing attachment of aminoacyl - tRNA
LDL

25. characterize x linked dominant
Alpha and beta tubulin - dimers have two GTP bound
Ketone - methyl
Promotor - TATA box - and CAAT box - AT rich
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

26. What is the TX for CF and What does it do
Acetyl - CoA
Site of steroid synthesis and detoxification of drugs and poisons
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Polycystic liver disease - berry aneurysm - mitral valve prolapse

27. What ribosomes do eukaryotes have
Cytosol - F 1 -6 BP to fructose 6 Phosphate
O- oligosaccharaides
40 - 60 - 80
30 - 50 - 70

28. What is the function and name of vit B6
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
Unmethylated - newly synthesized - HNPCC
Kidney - ears - eyes
Reads usual codon but inserts wrong AA

29. What step of uric acid synthesis does xanthine oxidase catalyze
Tryosine hydroxylase
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Hypoxanthine to xanthing and xanthine to uric acid
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

30. What is the order of severity for the different types of mutations
ATP
Nonsense > missense > silent
HVA
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase

31. What is a silent mutation
Acetly- CoA - CO2 - NADH
Assistance of upper extremities to stand up
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Same AA - often base change in 3rd position of codon (tRNA wobble)

32. What defects characterize DiGeorge syndrome
Alanine
Acetyl - CoA
Thymic - parathyroid and cardiac
AMP - fructose 2 -6 BP

33. Which type of chromatin is condensed - transcriptionally inactive - sterically inaccessible?
X linked frame shif mutation
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Heterochromatin = HighlyCondensed
VMA

34. What are cyclins
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Phosphofructokinase 1
Keep glutathione reduced so it can detoxify free radicals and peroxides
RRNA

35. decreases In what substances can cause PKU
Hypoglycemia
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Particular sequence of DNA where replicatino begins - may be single of multiple
LDL

36. What causes Down syndrome
Reads usual codon but inserts wrong AA
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

37. What other inflammatory process can induce a hemolytic anemia in NADPH defieicnt patients
RNA
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Type II
Infection - free radicals generated by inflammatory response

38. What is the RDE of cholesterol synthesis
Medial dorsal nucleus of thalamus - mamillary bodies
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Nissl body - enzyme and NTs
HMG- CoA reductase

39. What is the prevalence of an X- linked recessive disease in males and in females
ATP
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
Q -
Colchicine

40. 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
NF2 on chromosome 22
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
LDL

41. 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
Stop codon is recognized by release factor - and completed protein is released from ribosome
LDL
Facial flushing

42. Where are cytosolic and organellar proteins made
Free ribosomes
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Failure to track objects or develop a social smile
Reads usual codon but inserts wrong AA

43. What is trimming
Removal of N or C termal propeptides from zymogens to generate mature proteins
IMP precursor
Defect in fibrillin
Must be both activated and inactivated for cell cycle to progress

44. What is the smallest mutation a mircoarray can detect
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Glycine
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
SNP

45. What is axonemal dynein
Cofactor for LPL
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Changed AA (convservative - new AA is similar in chemical structure)
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus

46. What does DNA ligase do
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Seals.

47. What apolipoprotein is on LDL
Dec methionine - inc cystiene - inc B12/folate
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
B100
Tropoelastin with fibrillin scafolding

48. RNA poly can't proofread - but What can it do
Actin and myosin
LCAT (lecithin cholesterol acyltransferase)
Initiate chains
Transfers methyl units

49. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
RER
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Conversion of NE to epi

50. What kind of RNA is transported out of the nucleus
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
G6PD
Only processed RNA
Inhibits 50S peptidyltransferase