Salvage Pathway Of Purine Nucleotides

Salvage pathway of purine nucleotide synthesis

Q. 1 The purines salvage pathway is for:
 A Hypoxanthine and Xanthine
 B Hypoxanthine andAdenine
 C Adenine and Guanine
 D Xanthine and Guanine
Q. 1 The purines salvage pathway is for:
 A Hypoxanthine and Xanthine
 B Hypoxanthine andAdenine
 C Adenine and Guanine
 D Xanthine and Guanine
Ans. B

Explanation:Hypoxanthine andAdenine


Q. 2

Which among the following are the substrates needed for purine salvage pathway?

 A

Hypoxanthine and Xanthine

 B

Hypoxanthine and Adenine

 C

Adenine and Guanine

 D

Xanthine and Guanine

Q. 2

Which among the following are the substrates needed for purine salvage pathway?

 A

Hypoxanthine and Xanthine

 B

Hypoxanthine and Adenine

 C

Adenine and Guanine

 D

Xanthine and Guanine

Ans. B

Explanation:

Conversion of purines, their ribonucleosides, and their deoxyribonucleosides to mononucleotides involves “salvage reactions”.
The more important mechanism involves phosphoribosylation by PRPP of a free purine (Pu) to form a purine 5′-mononucleotide (Pu-RP). Phosphoryl transfer from ATP, catalyzed by adenosine- and hypoxanthine-phosphoribosyl transferases, converts adenine, hypoxanthine, and guanine to their mononucleotides. 
 
A second salvage mechanism involves phosphoryl transfer from ATP to a purine ribonucleoside. Phosphorylation of the purine nucleotides, catalyzed by adenosine kinase, converts adenosine and deoxyadenosine to AMP and dAMP. Similarly, deoxycytidine kinase phosphorylates deoxycytidine and 2′-deoxyguanosine, forming dCMP and dGMP.
 
Ref: Rodwell V.W. (2011). Chapter 33. Metabolism of Purine & Pyrimidine Nucleotides. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper’s Illustrated Biochemistry, 29e.

 


Q. 3

Salvage pathway of purine biosynthesis is important for ‑

 A

Liver

 B

RBCs

 C

Kidney

 D

Lung

Q. 3

Salvage pathway of purine biosynthesis is important for ‑

 A

Liver

 B

RBCs

 C

Kidney

 D

Lung

Ans. B

Explanation:

 

Purine nucleotide synthesis occurs by two pathways :

1.De novo synthesis

2.Salvage pathway

Liver is the major site of purine nucleotide biosynthesis (de novo).

Certain tissues cannot synthesize purine nucleotides by de novo patyway, e g. brain, erythrocytes and polymor­phonuclear leukocytes.

These are dependent on salvage pathway for synthesis of purine nucleotides by using exogenous purines, which are formed by degradation of purine nucleotides synthesized in liver.

Quiz In Between


Q. 4 Salvage pathway of purine nucleotide synthesis are used by all except ‑

 A

Brain

 B

Liver

 C

RBC

 D

Leukocytes

Q. 4

Salvage pathway of purine nucleotide synthesis are used by all except ‑

 A

Brain

 B

Liver

 C

RBC

 D

Leukocytes

Ans. B

Explanation:

 

Purine nucleotide synthesis occurs by two pathways :-

1.De novo synthesis

2.Salvage pathway

Liver is the major site of purine nucleotide biosynthesis (de novo).

Certain tissues cannot synthesize purine nucleotides by de novo patyway, e g. brain, erythrocytes and polymorphonuclear leukocytes.

These are dependent on salvage pathway for synthesis of purine nucleotides by using exogenous purines, which are formed by degradation of purine nucleotides synthesized in liver.


Q. 5 Salvage pathway of purine nucleotide synthesis are used by all except ‑

 A

Brain

 B

Liver

 C

RBC

 D

Leukocytes

Q. 5

Salvage pathway of purine nucleotide synthesis are used by all except ‑

 A

Brain

 B

Liver

 C

RBC

 D

Leukocytes

Ans. B

Explanation:

Ans. is ‘b’ i.e., Liver

  • Purine nucleotide synthesis occurs by two pathways :
  • De novo synthesis
  • Salvage pathway
  • Liver is the major site of purine nucleotide biosynthesis (de novo).
  • Certain tissues cannot synthesize purine nucleotides by de novo patyway, e g. brain, erythrocytes and polymorphonuclear leukocytes.
  • These are dependent on salvage pathway for synthesis of purine nucleotides by using exogenous purines, which are formed by degradation of purine nucleotides synthesized in liver.

Quiz In Between



Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this:
Malcare WordPress Security