Control and Co-ordination — BIOLOGY STD 12 Science — Question

What is biodiversity? Explain genetic diversity with suitable example.

With the help of a suitable diagram, describe the conducting system of human heart.

In a field of sugarcane, all the plants have been damaged during an epidemic of a fungal disease, whereas, in another field in the same area, there were many plants that were not affected by the disease.

1. Explain the reason for this observation.
2. An expert explains to the farmer, how the unaffected plants can be used to increase their number. Can you enumerate them?
3. Is there any method to recover disease-free plant from diseased ones.
4. What values are shown by the expert?

Explain how Ti plasmid of Agrobacterium tumefaciens acts as a vector for transferring genes to plants?

1. Draw a labelled longitudinal view of an albuminous seed.
2. How are seeds advantageous to flowering plants?

Look at the figure below depicting lac operon of E.coli.

1. What could be the series of events when an inducer is present in the medium in which E. coli is growing?
2. Name the Inducer.

Observe the given diagram and answer the questions based on it.(a) Which apparatus is shown in the given diagram ?
(b) What is the function of this apparatus?
(c) What are the reactions that can take place in blocks 1, 2, and 3?

A flower of tomato plant following the process of sexual reproduction produce 240 viable seeds.
Answer the following questions giving reasons:
How many megaspore mother cells were involved?

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

a.	Bacteria	____________
b.	Banyan	____________
c.	Deer	____________
d.	Fish	____________

Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyse the situation with the background of gametogenesis and provide or give suitable explanation.