Out of the following hydrogen bonding schemes shown by…..which one corresponds to the weakest hydrogen bond in a given solvent condition?

• O-H…..O<

• N-H….O<

• O-H….N<

• N-H….N<     

Which peptide bond(s) marked as a, b, c, d and e will be broken when the following oligopeptide is treated with trypsin at pH 7.0?

$\mathrm{Lys} \stackrel{\mathrm{a}}{\to } \mathrm{Arg} \stackrel{\mathrm{b}}{\to } \mathrm{Pro} \stackrel{\mathrm{c}}{\to } \mathrm{Lys} \stackrel{\mathrm{d}}{\to } \mathrm{Arg} \stackrel{\mathrm{e}}{\to } \mathrm{Gly}$

• a, b, d, e

• b, d, e

• d, e

• d

An enzyme catalysed reaction was measured in the presence and absence of an inhibitor. For an uncompetitive inhibition.

• Only K_m is increased.

• Both K_m and V_max are decreased   

• Only V_max is decreased

• Both K_m and V_max are not affected

Nitrate reductase is an important enzyme for nitrate assimilation. Given below are some statements on nitrate reductase enzyme:

(A) Nitrate reductase of higher plants is composed of two identical subunits.

(B) One subunit of nitrate reductase contains three prosthetic groups.

(C) One of the prosthetic groups attached to both subunits is heme.

(D) One of the prosthetic groups complexed with pterin is magnesium.

Which of the following combination of statements on nitrate reductase mentioned above is correct?

• A, B and C   

• A, C and D

• B, C and D

• A, B and D

From the following statements:

A. Triose phosphate is utilized for the synthesis of both starch and sucrose.

B. Triose phosphate is translocated to cytosol from chloroplast.

C. Triose phosphate is confined to chloroplast and is utilized for synthesis of starch only.

D. Triose phosphate is translocated from cytosol to chloroplast.

Which one of the following combinations is correct regarding starch and sucrose synthesis during day time?

• A and B    

• B and C  

• C and D  

• D and A

A chemist synthesized three new chemical compounds, M1, M2and M3. The compounds were tested for their mutagenic potential and were found to be highly mutagenic. Tests were made to characterize the nature of mutations by allowing the reversion with other mutagens. The following results were obtained:

Mutations produced by	Reversed By- 2 Aminopurine	Rversed by - Nitrous acid	Reversed by - Hydroxyl amine	Reversed by - Acridine orange
M1	No	No	No	No
M2	Yes	Yes	No	No
M3	No	No	No	Yes

Which one of the following conclusions drawn regarding the nature of mutations by the compounds is correct?

• M1-transversion, M2-insertion, M3-deletion  

• M1-transition, M2-transversion, M3-insertion

• M1-insertion, M2-trnsition, M3-transversion

• M1-transversion, M2-transition, M3-insertion

A is converted to E by enzymes E_A, E_B, E_C, E_D. The K_m(M) values of the enzymes are 10^-2, 10^-4, 10^-5 and 10^-6 respectively. If all the substrates and products are present at a concentration of 10^-4 M and the enzymes have approximately the same V_max the rate limiting step will be:

The Gibbs free energy of binding of a ligand with a protein is determined using alorimetric measurements at 25°C. The value of del G° thus determined is 1.36 kcal/ mole. The binding constant for the ligand-protein association is:

• 1.30 x 10^-12

• 0.10   

• 1.00

• 0.97

KCL (100 mM) was entrapped inside large unilamellar vesicles. A diffusion potential across the bilayer can be generated by diluting with buffer containing.

• 100mM KCL a protonophore

• 100mL NaCl and protonophore

• 100mM KCl and a K⁺ specific ionophore.

• 100mM NaCl and a K⁺ specific ionophore.   

Two moles each of O₂ and H₂ are in two separate containers. The two are made to react in a third container to form water vapor until. H₂ is exhausted. When the temperature of the mixture in the third container was restored to 150°C, its pressure became 1 atmosphere. The volume of the third container must be

• V₀

• $\frac{5{\mathrm{V}}_0}{4}$

• $\frac{3{\mathrm{V}}_0}{2}$     

• 2V₀