Environmental Issues — BIOLOGY STD 12 Science — Question

Explain the role(s) of the following in Biotechnology:

1. Restriction endonuclease.
2. Gel – electrophoresis.
3. Selectable markers in pBR322.

Mention the name of the causal organism, symptoms and the mode of transmission of the disease Amoebiasis.

In pea plants, the colour of the flower is either violet or white, whereas human skin colour shows many gradations. Explain giving reasons, how it is possible.

1. Which stage of Entamoeba histolytica is pathogen to humans?
2. Why E. histolytica does not have contractile vacuole?
3. Which form of E. histolytica serves for transmission of the parasite?

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.

Where does triple fusion take place in a flowering plant? Why is it so called? Mention its significance.

Trace the life-cycle of malarial parasite in the human body when bitten by an infected female Anopheles.

'Sperm donation can help infertile couples'. Justify. In which type of cases, such sperm donation is helpful?

Name the source of smack. Mention one way in which it affects the human body.

Write the steps you would suggest to be undertaken to obtain a foreign-gene-product.