Each of the nine glycolytic intermediates between glucose and pyruvate is phosphorylated. The phosphoryl groups seem to have many functions such as,

a) The plasma membrane generally lacks transporters for phosphorylated sugars, the phosphorylated glycolytic intermediates cannot leave the cell

b) After the initial phosphorylation, further energy is necessary to retain phosphorylated intermediates in the cell, despite the large difference in their intracellular and extracellular concentrations

c) Phosphoryl groups are essential components in the enzymatic conservation of metabolic energy, Energy released in the breakage of phosphoanhydride bonds is partially conserved in the formation of phosphate esters such as glucose 6-phosphate

d) Binding energy resulting from the binding of phosphate groups to the active sites of enzymes lowers the activation energy and increases the specificity of the enzymatic reactions

which of the following functions shows Importance of Phosphorylated Intermediates?

TLS Online TPP Program

#Question id: 30106

#Unit 1. Molecules and their Interaction Relevant to Biology

If a cell has an adequate supply of adenine nucleotides but requires more guanine nucleotides for protein synthesis:

1. Glutamine-PRPP amidotransferase will not be fully inhibited.

2. AMP will be a feedback inhibitor of the condensation of IMP with aspartate.

3. ATP will stimulate the production of GMP from IMP.

4. ATP will inhibit nucleoside diphosphate reductase.

TLS Online TPP Program

#Question id: 30107

#Unit 1. Molecules and their Interaction Relevant to Biology

Major controls of de novo AMP synthesis include:

1. allosteric inhibition by GMP.

2. allosteric inhibition by AMP.

3. availability of PRPP.

4. stimulation by GTP.

TLS Online TPP Program

#Question id: 30108

#Unit 1. Molecules and their Interaction Relevant to Biology

Aspartate plays a role in all of the following EXCEPT:

TLS Online TPP Program

#Question id: 30109

#Unit 1. Molecules and their Interaction Relevant to Biology

Allopurinol is an inhibitor of xanthine oxidase. Administration of allopurinol to a patient with gout and normal HG-PRT levels would be expected to lead to all of the following EXCEPT:

TLS Online TPP Program

#Question id: 30110

#Unit 1. Molecules and their Interaction Relevant to Biology

The ribose phosphate group of purine nucleotide is taken from which compound?

TLS Online TPP Program

#Question id: 30111

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the source of the C-2 during the de novo biosynthesis of pyrimidines?