Question

1. Discuss reasons why bacteria divide at a much faster rate than plant and animal cells. (b) Discuss the process by which bacterial cells reproduce.

(c) Discuss three methods of asexual reproduction in eukaryotic organisms. (d) Give an example of each type of asexual reproduction in eukaryotes.

Answer 1

a. Bacteria reproduce by binary fission which is very similar to mitotic division taking place in eukaryotic cells of plants and animals. Mitosis causes the organism to grow larger or replace old, worn-out cells with new ones. In the case of bacterium which constitutes a prokaryotic cell division isn’t just a means of making more cells for the body. Instead, it’s actually how bacteria reproduce or add more bacteria to the population. Thus bacteria divide at a much faster rate than plant and animal cells.

b. Binary fission proceeds with the replication of DNA inside the bacterial cell. It contains circular DNA with a single origin. The bacterial chromosome is found in a specialized region of the cell called the nucleoid. During DNA replication bacteria cell elongates, a septum is formed between the elongated cell which begins as a constriction and ends in the separation of two daughter cell with the equal distribution of replicated DNA.

c. Asexual reproduction occurs in many ways in eukaryotes which produce identical cells at the end. Few methods are-

1. By spore formation- few plants(bryophytes, fern and few gymnosperms) and fungi reproduce through spore formation. Spore is formed and it germinates to form a new organism when favourable conditions are present.

2. Budding- Formation of buds which are a kind of outgrowths occurs in many plants and animals species. These buds finally detach to produce the entire body.

3. Vegetative reproduction- many plants have evolved different mechanisms which enable them to continue their generations by means of vegetative reproduction where any vegetative part such as roots, stems or leaves can give rise to an entire plant.

d. spore formation - fungi

vegetative reproduction-   Plant structures allowing natural vegetative propagation include bulbs, rhizomes, stolons and tubers.

Bidding - budding in Hydra