question_answer

(i) Draw a labelled longitudinal section of an albuminous see

(ii) How are seeds advantageous to flowering plants?

Or

Differentiate between microsporogenesis and megasporogenesis. Name the structures formed at the end of the two events.

Answer:

(i) Longitudinal section of maize, an albuminous seed is given below
(ii) Seeds are advantageous to flowering plants in the following ways
(a) These are the final product of sexual reproduction and are source of variation.
(b) Since reproductive processes, such as pollination and fertilisation of seed plants are independent of water, seed formation is more dependable.
(c) Seeds have better adaptive strategies for their dispersal in the new habitat.
(d) Hard seed coat provides protection to the young embryo.
(e) They form the basis for agriculture.
(f) Seeds provide nourishment to the developing seedlings.
Or
Differences between microsporogenesis and megasporogenesis are given below
Microsporogenesis	Megasporogenesis
It is the formation of microspores or pollen grains from diploid microspore mother cell.	It is the formation of haploid megaspores from diploid megaspore mother cell.
It occurs inside mierosporangium or pollen sac of an anther.	It occurs inside the megasporangium or an ovule.
There are numerous functional microspore mother cells.	There is generally a single functional megaspore mother cell.
All the products of microsporogenesis are functional.	Only one megaspore is functional, while other get degenerated.
The products of mierosporogenesis give rise to the male gametophyte.	The functional product of megasporogenesis gives rise to the female gametophyte or embryo sac.
Structures formed at the end of events These are as follows
(i) Microsporogenesis - Microspores (pollen grains)
(ii) Megasporogenesis - Megaspores (embryo sac).