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Class 12th Biology 2012 Set1 Outside Delhi Board Paper Solution

Question 22

Explain the function of each of the following:
i. Coleorhiza
ii. Umbilical cord
iii. Germ pores

(a) The coleorhiza is a protective sheath that envelops the radicle in certain plants that is penetrated by the root in germination. It helps in protecting the radicle.
(b) The umbilical cord serves as a blood source for the foetus and as a means of transferring nutrients, proteins, fats, as well as vitamins to the foetus. It also transfers waste products and deoxygenated blood away from the foetus.
(c) The germ pore is apertures in the exine layer of the pollen grain where the sporopollenin is absent. The germ pore helps in the formation of the pollen tube and the release of the male gametes during fertilization.