LIFE SCIENCE PART C (DECEMBER 2016) 2016

From the following statements,a. Hydrogen, Deuterium and Tritium differ in the number of protonsb. Hydrogen, Deuterium and Tritium differ in the number of neutronsc. Both Deuterium and Tritium are radioactive and decay to Hydrogen and Deuterium, respectivelyd. Tritium is radioactive and decays to Heliume. Carbon-14 decays to Nitrogen-14f. Carbon-14 decays to Carbon-13Pick the combination with ALL correct statements.

From the following statements,a. For a reaction to occur spontaneously the free energy change must be negativeb. The interaction between two nitrogen molecules in the gaseous state is predominantly electrostaticc. By knowing bond energies, it is possible to deduce whether the bond is covalent bond or hydrogen bondd. Hydrophobic interactions are not important in a folded globular proteinPick the combination with ALL WRONG statements.

The following are four statements on peptide/ protein conformation:
a. Glycine has the largest area of conformationally allowed space in the Ramachandran plot Φ and of ψ
b. A 20-residue peptide that is acetylated at the N-terminus and amidated at the C-terminus has Φ = –60° (±5), ψ = –30° (±5) for all the residues. It can be concluded that conformation of the peptide is helix-turn-strand
c. The allowed values of Φ, ψ for amino acids in a protein are not valid for short peptides
d. A peptide Acetyl-A1-A2-A3-A4-CONH2 (A1- A4 are amino acids) adopts a well defined β - turn. The dihedral angles of A2 and A3 determine the type of β-turn
Choose the combination of correct statements.

A researcher investigated a set of conditions for a protein with an isoelectric point of 6.5 and also binds to calcium. This protein was subjected to four independent treatments: (i) pH 6.4, (ii) 10% glycerol, (iii) 10 mM CaCl2, (iv) 40% ammonium sulphate. This was followed by centrifugation and estimation of the protein in the supernatant. The results are depicted in the graph below:Which of the following treatments best represents the results shown in the graph?

In the biosynthesis of purine:

A researcher was investigating the substrate specificity of two different enzymes, X and Y, on the same substrate. Both the enzymes were subjected to treatment with either heat or an inhibitor which inhibits the enzyme activity. Following are the results obtained where a=inhibitor treatment, b=heat treatment and c=control.Which of the following statements is correct?