1st bio quiz 425

BIO Quiz (1427 H)

1)PRPP :
- it intact needs HMP pathway.
- Inhibited by P1 and is activated by ATP.
- Added to purine ring at the last step in purine formation.
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2) Ribonucleotide reductase :
- it is a monomer that have regulatory activity.
- Thioredoxin donates the H atom to the enzyme.
- It is inhibited by d-ATP 
- NADPH is the immediate donor of hydrogen.
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3) According to purine and pyrimidine inhibitor:
- sulfonamide inhibits human ……
- trimethoprim is an anti-cancer drug.
- Folic acid analog blocks the action of dihydrofolate reductase.
- Methotrexate
- PABA is toxic to the dividing cells of bone marrow.

4) Cytidine:
- It is a mononucleotide.
- It is a ribonucleoside.
- Its purine base is attached to ribose sugar.
- It is formed by deoxyribose and cytosine.
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5) the ester linkage is linked to :
- carbon # 1
- carbon#2
- carbon#3
- carbon#4
- carbon#5

6) According to ADA all are true EXCEPT: 
- it is autosomal recessive disease.
- First genetic disease treated by gene therapy.
- It blocks the production of ribo…
- Highest activity is in lymphocyte.
- It is expressed in cytosol.
7) Adenylate kinase : 
- d-AMP is one of its substrates.
- It acts on any type of purine bases.
- It uses NTP as a source of its phosphate group.
- It has the least activity in liver.
- Its reaction is irreversible.

8) Regarding the synthetic process of purine and pyrimidine:
- Hypoxanthin is the nitrogenous base of IMP.
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9) Which of the following compounds donate nitrogen atom to purine and pyrimidine :
- glycine.
- N10 - Formyltetrahydrofolate.
- Aspartic acid.
- Glutamic acid.
- Aspargine.

10) Mycophenolic acid : (All are true except)
- Attack B , T cells.
- it inhibits the action of IMP dehydrogenase.
- inhibits the production of AMP.
- It is used to prevent the graft rejection.
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TRUE and FALSE part :
1) Allantoin is the end product of degradation of purine in human.
2) 5-flurouracil is metabolically converted to 5-FdTMP.
3) In lesch-nyhan syndrome, the de novo synthesis of purine is increased.


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