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TLS Online TPP Program

#Question id: 150

How do the pKa values of an ionizable side chain compare when the amino acid is free versus when it is in a polypeptide chain?

#Unit 1. Molecules and their Interaction Relevant to Biology

  1. The pKa of the side chain is independent of whether the amino acid is in a polypeptide chain or is free.

  2. The pKa of the side chain is always lower for the free amino acid.

  3. The pKa of the side chain may be lower or higher in a polypeptide chain due to weaker inductive effects and differences in their microenvironments.

  4. The pKa of the side chain is usually higher in a polypeptide chain due to stabilization from nearby residues in the three-dimensional structure.

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TLS Online TPP Program

#Question id: 32406

#Unit 1. Molecules and their Interaction Relevant to Biology

Find the order in which they appear in the TCA cycle.
TLS Online TPP Program

#Question id: 32407

#Unit 1. Molecules and their Interaction Relevant to Biology

Deuterated acetyl-coenzyme A (-CD3 instead of –CH3) was used in an experiment to study the TCA cycle. Upon analysis of the metabolites, it was found that deuterium (D) was present in a wide variety of compounds; even compounds not associated with the citric acid cycle. This is due to
TLS Online TPP Program

#Question id: 32408

#Unit 1. Molecules and their Interaction Relevant to Biology

What would result if 14CO2 were incorporated into the TCA cycle via the pyruvate carboxylase reaction.
TLS Online TPP Program

#Question id: 32409

#Unit 1. Molecules and their Interaction Relevant to Biology

What will be the fate if methyl-labeled acetyl-CoA was fed to the conventional TCA cycle.
TLS Online TPP Program

#Question id: 32410

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following statements is false.
a. Pyruvate dehydrogenase is inhibited by NADH.
b. Pyruvate dehydrogenase is inhibited by ATP.
c. Citrate synthase is inhibited by NADH.
d. Succinyl-CoA activates citrate synthase.
e. Acetyl-CoA activates pyruvate carboxylase.
TLS Online TPP Program

#Question id: 32411

#Unit 1. Molecules and their Interaction Relevant to Biology

Activity of citrate synthase from pig heart tissue shows a sigmoid dependence on the concentration of acetyl-CoA. Which of the following statement is correct.