Reproduction in Lower and Higher Animals — BIOLOGY STD 12 Science — Question

Name and explain the technique that helps in separation of DNA fragments for recombinant DNA technology experiments. How can these separated DNA fragments be visualised?
OR

1. Name the technique used for the separation of DNA fragments.
2. Write the type of matrix used in this technique.
3. How is the separated DNA visualised and extracted for use in recombinant DNA technology?

Differentiate between an annual and a biennial plant. Provide one example of each.

Describe the two major events that occur during embryogenesis and mention their significance.

Identify the figure given alongside.

Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

Enumerate the complications that untreated STDs can lead to.

1. Mention the property that enables the explants to regenerate into a new plant.
2. A banana herb is virus-infected. Describe the method that will help in obtaining healthy banana plants from this diseased plant.

Draw a diagram of L. S. of an anatropous ovule of an angiosperm and label the following parts.

1. Nucellus.
2. Integument.
3. Antipodal cells.
4. Secondary nucleus.

1. Write your observations on the variations seen in the Darwin’s finches shown above.
2. How did Darwin explain the existence of different varieties of finches on Galapagos Islands?

Explain how the adrenal medulla and sympathetic nervous system function as a closely integrated system.