MODEL PAPER 10 — BIOLOGY STD 12 Science — Question

1. Explain how to find whether an E.coli bacterium has transformed or not, when a recombinant DNA bearing ampicillin-resistant gene is transferred into it.
2. What does the ampicillin-resistant gene act as, in the above case?

1. Name the lymphoid organ in humans where all the blood cells are produced.
2. Where do the lymphocytes produced by the lymphoid organ mentioned above migrate and how do they affect immunity?

Given below are the events that are observed in an artificial hybridization programme. Arrange them in the correct sequential order in which they are followed in the hybridisation programme.
(a) Re-bagging (b) Selection of parents (c) Bagging (d) Dusting the pollen on stigma (e) Emasculation (f) Collection of pollen from male parent.

List any two adverse effects of particulate matter on human health.

How are the consecutive nucleotides linked together in a polynucleotide strands?

Explain the function of each of the following:
Coleorhiza

How is Darwin's concept of evolution different from that of de Vries?
OR
How is mutation explained by Hugo de Vries different from the Darwinian variations?

OR
How do Darwin and de Vries differ in their views on the mechanism of evolution of life on earth?

Banana is a parthenocarpic fruit whereas oranges show polyembryony. How are they different from each other with respect to seeds?

you are given a tall pea plant, how would you find out its genotype? Explain.

Explain the relationship between CFC's and Ozone in the stratosphere.