September 2023

Q. “The driver applied the_________as soon as she approached the hotel where she wanted to take a__________.” The words that best fill the blanks in the above sentence are (A) brake, break                         (B) break, break (C) brake, brake                         (D) break, brake Ans: Brake, Break

Q. A rod shaped bacterium has a length of 2 µm, diameter of 1 µm and density the same as that of water. If proteins constitute 15% of the cell mass and the average protein has a mass of 50 kDa, the number of proteins in the cell is (1 Da = 1.6 ´ 10-24g)

Q. The product of complete digestion of the plasmid shown below with EcoRI and HaeIII was purified and used as a template in a reaction containing Klenow fragment of DNA polymerase, dNTPs and [a-32P]-dATP in a suitable reaction buffer. The product thus obtained was purified and subjected to gel electrophoresis followed by autoradiography. The number

Q. Consider a simple uni-substrate enzyme that follows Michaelis-Menten kinetics. When the enzyme catalyzed reaction was carried out in the presence of 10 nM concentration of an inhibitor, there was no change in the maximal velocity. However, the slope of the Lineweaver-Burk plot increased 3-fold. The dissociation constant for the enzyme-inhibitor complex (in nM) is

Q. First order deactivation rate constants for soluble and immobilized amyloglucosidase enzyme are 0.03 min-1 and 0.005 min-1, respectively. The ratio of half-life of the immobilized enzyme to that of the soluble enzyme is (rounded off to the nearest integer)        Ans: 6 to 6

Q. Consider the following alignment of two DNA sequences: Assuming an affine gap scoring scheme of an identity matrix for substitution, a gap initiation penalty of 1 and a gap extension penalty of 0.1, the score of the alignment is (up to one decimal place) Ans: 1.8 to 1.9

Q. At the end of a batch culture, glucose solution is added at a flow rate of 200 ml/h. If the culture volume after 2 h of glucose addition is 1000 ml, the initial culture volume (in ml) is   Ans: 600 to 600

Q. Yeast converts glucose to ethanol and carbon dioxide by glycolysis as per the following reaction: Assuming complete conversion, the amount of ethanol produced (in g) from 200 g of glucose is (up to two decimal places) Ans: 102.00 to 103.00

Q. In a chemostat, the feed flow rate and culture volume are 100 ml/h and 1.0 L, respectively. With glucose as substrate, the values of µmax and Ks are 0.2 h-1 and 1 g/L, respectively. For a glucose concentration of 10 g/L in the feed, the effluent substrate concentration (in g/L) is          Ans: 1