(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.
Perisperm |
Endosperm |
Perisperm is the remnant of nucellus which are persistent. It encloses the embryo and provides nourishment to it in certain seeds. |
Endosperm is the tissue formed after double fertilisation. It surrounds, stores food and provide nourishment to the embryo in an angiosperm seed. |
It is diploid in nature. |
It is triploid in nature because it is formed as a result of triple fusion. |
Example- Black pepper |
Example- Wheat |