Biochem 125-final 2005

(B. Sc. Biochemistry) Second Semester 2005 Subject: Biochem 125 (Biomolecules I)

Full Marks: 100 Pass Marks: 45 Time: 3 hours

Candidates are required to give their answers in their own words as far as practicable. The figure in the margin indicates full marks. (3× ×14 = 42)

Group (A) Long Questions (Any three)

1. "Oligosaccharide – Lectin interaction mediates many biological processes". Explain and illustrate the statement with as many examples as possible. 2. Explain principle, methodology and application of affinity chromatography. 3. Describe the factors responsible for the purification of protein. 4. What are the levels of protein structure? Discuss in detail tertiary structure of protein. Group (B) Short Questions: (Any six) (6× ×7 = 42) 1. Explain the structure of peptidoglycans present in bacterial cell wall. 2. Explain with schematic diagram of the lipopolysaccharide of the outer membrane of Salmonella typhimurium. 3. Determine the amino acid sequence of a poly peptide from the following results: (a) Complete hydrolysis of the peptide yield the following amino acids: Ala, Arg, Gly, 2Lys, Met, Phe, Pro, 2 Ser, Tyr, Val (b) Treatment with Edman's reagent gives PTH-Val. (c) Carboxypeptidase A releases – Val (d) Treatment with cyanogenbromide yield the following two species: (i) Ala, 2 Lys, Phe, Pro, Ser, Tyr (ii) Arg, Gly, Met, Ser, Val (e). Treatment with chymotrypsin yields the following three peptides (i) 2 Lys, Phe, Pro (ii) Arg, Gly, Met, Ser, Tyr, Val (iii) Ala, Ser (f) Treatment with trypsin yields the following these peptides: (i) Gly, Lys, Met, Tyr (ii) Ala, Lys, Phe, Pro, Ser (iii) Arg, Ser, Val 4. Discuss the titration curves of amino acid. How could the pI value of monoaminodicarboxylic acid and diamino mono carboxylic acid be calculated? 5. Describe the principle and application of SDS – PAGE. 6. How are mixture of amino acids separated by ion exchange chromatography? Describe. 7. What are the weak interactions that affect the stability of protein? 8. Discuss denaturation and renaturation of protein. (2× ×8 = 16)

Group (C) Very Short Questions: (Any eight) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

What is Hyaluronate? Define glycobiology? What do you mean by a glycosidic bond? Draw the structure of Histidine and Arginine. What do you understand by the term isoionic point and isoelectric point? What is protein? Write short notes on isoelectric focussing. What do you understand by the term activity and specific activity of an enzyme? Why is spacer used in affinity chromatography? Write a short note on Ramachandran Plot. The peptide bond is rigid and planar. Why? What are supramolecular complexes? ***