Thapar University 2006 M.Sc Bio Chemistry Cell and Molecular Biology - Question Paper

a)

What are the physical mutagens? How do they affect cellular components?

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b)

Differentiate between point mutations & gross mutations. Highlight on

anv three tvoes of Doint mutations.

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c)

Provide the mechanism of action of the following chemical mutagens: 5-Bromouracil. Acridine orange &. Nitrous acid

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OR

a)

Distinguish between prototrophs and auxotrophs with examples.

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b)

Give vour critical comments on temDerature sensitive and constitutive mutants.

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c)

Distinguish between mismatch DNA repair' and base excision repair. Also name

the enzyme/protein components involved in the first case.

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Attempt any three of the following questions:

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a)

What are the major events associated with general recombination?

b)

In terms of biochemical attributes distinguish between DNA polymerase I and DNA polymerase III of E. coli.

c)

Differentiate between '0-mode* & 'o-mode of DNA replication.

d)

What are the major control points involved in the regulation of gene expression.

a)

Write a short note on the Lac repressor. Can we dissect its biochemical functions?

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b)

Give your critical comments on the phenotype of the following any four bacterial

mutants:

lacYt cva pro(Ts)/pro , lacf*, lacfAacI

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a)

What are the cellular components involved in the initiation of protein synthesis in

bacteria?

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b)

You are given a bacterial DNA sequence of 1.5 kb. How do you establish the

presence of a functional gene in this DNA fragment?

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c)

The genetic code is degenerate but unambiguous*. W'hat do you mean by this

statement? What is codon usage?

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d)

Write a brief note on Polvnucleotide PhosDhorvlase.

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a)

How do you establish that ribosomes are the site of protein synthesis?

b)

What are the steps involved in the processing of eukaryotic primary transcript?

c)

How do you demonstrate the transmembrane arrangement of membrane proteins?

d)

Show the dynamics of tubulin polymerization in vitro.

e)

With the help of diagram describe the following: Uniport, Symport & Antiport

6. a)

Some enzymes do require lipid environment for proper function. Provide evidence in support of this statement.

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b)

What is subcellular fractionation? What is its importance?

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c)

With the help of genetic approaches how do you study the mechanism of protein translocation in the yeast?

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