A woman with ‘O blood group’ marries a man with ‘AB blood group’. Work out the cross to show all the possible phenotypes and genotypes of the progeny with respect to blood groups. Explain the pattern of inheritance observed in this cross.

Charles Darwin during his famous sea voyage around the world in a ship (HMS Beagle), concluded that there has been gradual evolution of life.

Answer the following questions:

(a) What is his theory known as? Explain the salient features of his theory.

(b) Name a scientist who arrived at a similar conclusion as that of

Charles Darwin.

Draw a diagram of LS of Maize grain and label its any six parts.

Hershey and Chase carried out their experiment under three steps: (a) Infection, (b) Blending, and (c) Centrifugation. Explain each one of these steps that helped them to prove that DNA is the hereditary material.

OR

(a) Why does DNA replication occur within a replication fork and not in its entire length simultaneously?

(b) ‘‘DNA replication is continuous and discontinuous on the two strands within the replication fork.’’ Give reasons.

(a) What is the breeding of crops for enhancing their nutritional value called? Why is the need felt for enhancing the nutritional value of the crops?

(b) Rice, wheat and maize are the most commonly used food grains the world over. How have these grains improved in their nutritional value in comparison to their conventional varieties?

OR

(a) Write the scientific names of the source plants from where opioids and canabinoids are extracted.

(b) Write their receptor sites in the human body. How do these drugs affect the human beings?