Brood parasitism is a type of parasitism in birds in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them. For example, cuckoo (koel) lay its eggs in the nest of crow. During the course of evolution, the eggs of the parasitic bird have evolved to resemble the hosts egg in size and colour to reduce the chances of the host bird detecting the foreign eggs and ejecting them from the nest.
(a) Mention the cause and the body system affected by ADA deficiency in humans.
(b) Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the recipient cells.(a) Name the group of viruses responsible for causing AIDS in humans. Why are these viruses so named?
(b) List any two ways of transmission of HIV infection in humans, other than sexual contact.
(a) Draw a neat labelled diagram of a nucleosome.
(b) Mention what enables histones to acquire a positive charge.
