Q1 of 805 Page 1

Name the vegetative Propagules in (i) Potato, and (ii) Pistia.

Propagules the structure generated by plants, fungi and bacteria. In plants it’s a vegetative structure; it detaches from the plant and gives the new plant. The propagule structures of the plants are rhizomes, suckers and tubers.


I. Potatoes are propagated using asexual reproduction mode. Where the tubers, a thick, underground storage organ that develops from the end of potato root and emerges from the surface stem known as stolon. Potato tubers have stem buds which can sprout and grow a new above-ground stem. The tubers are rich in starch and storage of nutritious.


II. Propagation in Pistia is by offset. Offsets are branches arise from the stem and upper part of each branch and are curved bearing leaves and the lower portion carrying roots. When the branch gets separate, it grows independently forming a new plant.


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A group of youth were having a ‘rave party’ in an isolated area and was raided by police. Packets of ‘smack’ and syringes with needles were found littered around.

(a) Why is taking ‘smack’ considered an abuse?


(b) Write the chemical name of ‘smack’ and the name of its source plant.


(c) Syringes and needles used by the youth for taking the drug could prove to be very fatal. Why?


 25

Read the statement and answer the questions that follow.

A flower of brinjal has 520 ovules in its ovary. However, it produces a fruit with only 480 viable seeds.


(a) What could have prevented the rest of the 40 ovules from maturing into viable seeds ? Explain giving a reason.


(b) Describe the development of a dicot embryo in a viable seed.


(c) Why certain angiospermic seed are albuminous while others are ex-albuminous? Explain.


OR


(a) Name the hormones secreted and write their functions :


(i) by corpus luteum and placenta (any two).


(ii) during Follicular phase and parturition.


(b) Name the stages in a human female where:


(i) Corpus luteum and placenta co-exist.


(ii) Corpus luteum temporarily ceases to exist.


 2

Mention the combination(s) of sex chromosomes in a male and a female bird.

 3

A region of a coding DNA strand has the following nucleotide sequence:

– A T G C –


What shall be the nucleotide sequence in (i) sister DNA segment it replicates, and (ii) m-RNA polynucleotide it transcribes?