The titration curve of alanine shows the ionization of two functional groups with pKa values of 2.34 and 9.69, corresponding to the ionization of the carboxyl and the protonated amino groups, respectively. The titration of di-, tri-, and larger oligopeptides of alanine also shows the ionization of only two functional groups, although the experimental pKa values are different. The trend in pKa values is summarized in the table. Which of the following is a reason for this shift in pK values

TLS Online TPP Program

#Question id: 24217

#Unit 1. Molecules and their Interaction Relevant to Biology

Choose the correct statement of the following

a. In general, high acetyl-CoA or citrate are present, or when a high proportion of the cell’s adenylate is in the form of ATP, gluconeogenesis is favored.

b. When the level of AMP increases, it promotes glycolysis by stimulating PFK-1 by inhibiting FBPase-1

c. Phosphorylation of fructose 6-phosphate, catalysed by phosphofructokinase-2 (PFK-2)

d. Glucagon increases the cellular level of fructose 2,6 bisphosphate, stimulating glycolysis and inhibiting gluconeogenesis.

TLS Online TPP Program

#Question id: 24218

#Unit 1. Molecules and their Interaction Relevant to Biology

Phosphorylation of fructose 6-phosphate, catalysed by

TLS Online TPP Program

#Question id: 24219

#Unit 1. Molecules and their Interaction Relevant to Biology

When Fructose 2,6-bisphosphate binds to its allosteric site on PFK-1 results

TLS Online TPP Program

#Question id: 24220

#Unit 1. Molecules and their Interaction Relevant to Biology

Glucagon stimulates cAMP from ATP. Cyclic AMP then activates cAMP-dependent protein kinase, phosphorylates PFK-2/FBPase-2. Phosphorylation of this protein enhances its FBPase-2 activity and inhibits its PFK-2 activity resulting

TLS Online TPP Program

#Question id: 24221

#Unit 1. Molecules and their Interaction Relevant to Biology

Glucagon lowers the cellular level of fructose 2,6 bisphosphate by

TLS Online TPP Program

#Question id: 24222

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following reaction of glycolysis is irreversible

1. Glucose is converted to glucose 6-phosphate in the presence of the enzyme hexokinase.

2. Fructose 6-phosphate is converted to fructose 1,6-biphosphate in the presence of the enzyme phosphofructokinase.

3. Phosphoenolpyruvate is converted to pyruvate in the presence of the enzyme pyruvate kinase.

4. isomerization of glucose 6-phosphate to fructose 6-phosphate