Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Draw a schematic sketch of pBR322 plasmid and label the following in it:

1. Any two restriction sites.
2. ori and rop genes.
3. An antibiotic resistant gene.

Explain the effect on the characteristics of a river when urban sewage is discharged into it.

How do scientists extrapolate the total number of species on Earth?

Rearrange the following in the correct sequence to accomplish an important biotechnological reaction:

1. In vitro synthesis of copies of DNA of interest,
2. Chemically synthesised oligonucleotides,
3. Enzyme DNA-polymerase,
4. Complementry region of DNA,
5. Genomic DNA template,
6. Nucleotides provided,
7. Primers,
8. Thermostable DNA-polymers (From Thermus aquaticus),
9. Denaturation of dsDNA.

Gene therapy is an attempt to correct a genetic defect by providing a normal gene into the individual. By this the normal function can be restored. An alternate method would be to provide the gene product (protein/ enzyme) known as enzyme replacement therapy, which would also restore the function. Which in your opinion is a better option? Give reason for your answer.

Explain Hershey - Chase experiment. What was proved through this experiments?

Name the major enzymes involved in DNA replication.

Draw a schematic diagram of the E.coli vector PBR 322 and mark the following in it:

1. Ori
2. Rop
3. Ampicillin-resistant gene
4. Tetracycline-resistant gene
5. Restriction site BamHI
6. Restriction site EcoRI

Why do lepidoplerans die when they feed on Bt cotton plant? Explain how does it happen.

What is called antibody? Describe the structure of an antibody molecule.