Biochemistry of Nucleic Acids and Proteins — DU B. Sc. (Hons) Microbiology Previous Year Question Papers

1. (a) State whether the following statements are True or False giving reasons (any three) : 3×5=15 (i) The rate curve of an enzyme catalyzed reaction is a straight line. (ii) All amino acids essentially form a blue purple color complex with ninhydrin reagent. (iii) DNA is more prone to alkaline hydrolysis compared to RNA. (iv) Oxygen binding curve of hemoglobin is a hyperbola. Define activation energy and explain its role in enzyme catalysis. Write an example of an allosteric enzyme with its positive and negative modulators. 3 2. (a) Draw the structure of Uridylate and link it with Guanylate. 8 (b) How are enzymes classified ? Name the different classes along with their enzyme commission numbers, citing an example of each. 1+3+3=7 (c) Describe Michaelis-Menten kinetics of an enzymatic reaction. 7 Write an example of an non-protein amino acid and draw its structure. 1+2=3 3. Write short notes on the following (any three) : (a) Multienzyme complex (d) Theories of enzyme action 4. (d) What are essential amino acids ? Cite an example and draw its biochemical structure. 1+1+2=4 Describe the structure and function of Glutathione. 4 With the help of diagram trace the formation of different ionic species of Alanine that form upon its titration with NaOH. 6 Briefly write about the contributions of the following scientists (any two) : 2×2=4 (i) Alexander Rich (ii) Pauling and Corey (iii) Dorothy Hodgkin What are the salient features of Watson and Crick model of Differentiate between the following pairs (any three) : (a) Competitive and non-competitive enzyme inhibition (b) A and Z DNA (c) Secondary and tertiary level of protein structures (d) Prosthetic group and co-enzyme. 6. (a) Explain the following giving suitable example or diagram (any four): 4x4=16 (i) Hyperchromic effect (iv) Active site Peptide hormone (b) Define the term enzyme unit.