Biochem preoral!!

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Biochem preoral!!

Post  Betty on Wed May 05, 2010 12:28 pm

Goooooood luck!!!

For last 5 questions:

1. reaction of salicylic acid + acetic acid = acetylsalicylic acid (aspirin). You have to draw the structure
2. Calculation of pH of H2SO4 after dilution which is pH 4
3. Naming of the compound: methoxybenzene or methyl phenyl ether
4. Naming of the compound: propenoic acid
5. Draw the structure of Adenine

Some of the MCQs

1. There is one question on angiotensin 2 - aldosteron which is wrong and I pointed it out to her and she said she'll give a free mark . There is no answer
2. Properties of KMnO4. I think all the answers are correct.: it forms acidic sln (there's no other choice so i guess this is correct), its ox. state is VII, it dissolves in aq. solution and it is an oxidizing agent.
3. The compounds in the synthesis of fatty acids: the choices are FAD, carboxylase, reductase and either dehydrogenase or hydrogenase. Don't really remember. I think i got this question wrong.. reductase is def. correct. carboxylase no, fad no.
4. The properties of allosteric enzyme - it binds to a distinct site on enzyme and changes the shape of active site. Well i guess so... please recheck.
5. Typical reaction of isoprene = polymerization
6. NADH - it cannot cross mit. membrane, it usually goes into ETC and i think there's one more answer which i can't remember
7. Lactate dehydrogenase is released during myocardial infarction and situated in cytosol. The other choices are it has 4 subunits and it uses NADH to reduce lactate which is wrong.
8. Epi is produced from nor. thru = methylation
9. Glutathione role in RBC - reduction of H2O2
10. The reason why muscle cannot utilize glycogen to form glucose (i think this question is tricky). among the choices are it has no glucose-6 phosphatase, it has no phosphorylase, it cannot form glucose-6-p and 2 more choices i guess. but the correct one that i guess is it has no glucose-6 phosphatase.
11. properties of catalyst - this is kinda straight forward. I'm not sure if a question on eq. constant is a separate question or it's together with this q. but K should not change under the effect of catalyst. Whereas rate constant is only affected by temp - same applies here.
12. Testosterone and properties - remember it is anabolic hormone potentiating growth so one of the choices which is inducing protein catabolism is wrong. The other choices are it is a polypeptide which is wrong, and er i don't remember the rest but it's quite straight forward for the other choices.
13. Indole can be found in pyridoxin vitamin B6, tryptophan a.a
14.Albumin: carries free fatty acids, has lower weight than globulin.. there r other choices but if you choose either one you'll get the correct combination.
15. Ketogenic a.a - 2 choices which r correct (ketogenic a.a are phe, tyr, leu, lys, trp)
16. Oxidation of malic acid will give - oxaloacetic acid
17. Typical enzymes in citric acid cycle - dehydrogenase, hydrase
18. Choline is derived from Serine - i'm not sure if this came out in the test or i was just imagining it. I think it's got something to do with ethanolamine, the intermediate in formation of choline.
19. Compound used to transport long-chain fatty acids across mit. membrane - carnitine

1. Typical reaction of alcohol- answer was esterification.
2. Cortisol- u need to know structure which position is it hydroxylated and and wat r its functions e.g reduce effects of inflammation, protein anabolism.
3. Function of lipoprotein lipase-
4. Acetoacetate is reduced to-3 hydroxybutyric acid was the answer i think-ketone bodies.
5. For which metabolic degradation fumarate is the end product- answer I think is tyrosine n phenylalanine
6. Wat activates hormone-sensitive lipase?
7. Wat does sphingomyelin not contain? Answer was glucose
8. What is the effect of salicylic acid? Affects prostaglandin formation n some others i cant remember the options.
9. Uric acid is the product of metabolism of: pyrimidine was one of the answer
10. Action of phosphofructokinase answer was important step of glycolysis and fructose 6-P is the substrate to from 1,6 fructosebisphosphate.
11. Properties of CoQ- 1 of the answer was lipophillic see electron transport chain for details
12. Which type of bond is the least important to maintain 3-D structure of proteins?

Written part
1. Draw structure of serine
2. 5ml of hcl(conc 0.005ml/l) is taken n diluted to 100ml.wat is the ph of the solution.
3. Wat is the product of dehydration of malic acid? I tink its oxaloacetate c TCA cycle
4. Write down the name of some compd? I cant remember for sure i tink it was a benzene ring-O-CH2-CH3. i wrote ethyl phenyl ether.

-Draw and name the product of Acetic Acid and Salicylic acid (Aspirin/Aceto Salicylic Acid)
-Draw Adenine
-calculate the pH of 0.5mL of 0.005mol/L H2SO4 if it's diluted up to 0.5L (4.3)
-Name this [benzene ring]-O-CH3

-What is the function of testosterone
-Allosteric enzyme inhibitors work by (binding somewhere other than active site + cause conf. change)
-Catalyst stuff
-Which of these is not excreted in urine (uracil)
-something about Lactate dehydrogenase.

FA synthesis shuttle
Hg2Cl2 -Name(mercuri chloride or mercurous chloride) ...and properties.
KCr07 properties
Draw acrylic acid/propenoic acid..
Aldesterone secretion and affects..
Proteins of muscle
Same stuff...draw adenine...aspirin...rxns in TCA cycle...

draw fumaric acid

draw valine

delta amino mlevulonic acid is derived from ( me thinks suucinyl coa and glycine -- pyrrole sunthesis)

barium carbonate is soluble or not sluble in water

components of fatty acid synthase enzyme ( cysteine residue , and acp)

wht type of enzyme is utilized in the following reaction

glucose 6 phosphate -> glucose 1 phosphate
answer: mutase (me thinks)

a question on the equation gibbs free energy and entropy and enthalalpy

thrombin function ( me thinks : clevage of fibrinopepetideA &B from fibrinogen)

enzymatics markers of myocardial infarction


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