JAMB Biology 1978 Question 12

The following events take place during conjugation in Spirogyra 1. The protoplasm in each of the conjugating cells separate from the cell wall to form a gamete; the gamete of one filament passes through the conjugation tube to meet the gamete of the other filament 2. The zygote soon become surrounded by a thick brown wall to become zygospore which bursts after a short rest and germinates to produce a new filament 3. The nuclei of the gametes fuse to form a zygote 4. The protuberances meet and where they touch the cell-wall disappears so that a conjugation tube joining the two cells is formed 5. Protuberances appear on the walls of cells of two filaments of Spirogyra lying side by side opposite one another. Now, what is the correct sequence in which the above events occur?

1. A.1,2,3,4,5
2. B.1,2,4,5,3
3. C.3,4,5,2,1
4. D.5,4,1,3,2
5. E.5,4,3,1,2