Question

In spirogyra, asexual reproduction takes place by

• A. Breaking up filaments into smaller bits
• B. Division of a cell into two cells
• C. Division of a cell into many cells
• D. Formation of young cells from older cells.

Answer 1

The correct option is A

Breaking up filaments into smaller bits

The correct option is A.

Explanation of the correct option: -

1. Spirogyra reproduces sexually, asexually, and vegetatively. Spirogyra has a haplontic life cycle, which means that the dominant stage is a free-living haploid (n) gametophyte, while the sporophyte is represented only by the diploid zygote (2n).
2. Fragmentation is how plants reproduce. Vegetative reproduction is the favoured way of reproduction when the conditions are favourable.
3. Following fragmentation, the vegetative filament grows into a new filament. To generate a new filament, each piece goes through several divisions and elongations.
4. Fragmentation can occur as a result of mechanical injury or the disintegration of the middle lamella as the water's salinity and temperature vary.
5. When one cell's centre lamella protrudes into a neighbouring cell, the filament is broken.

Explanation of the incorrect options: -

Option B: - Mitosis is a necessary part of existence. A cell copies all of its components, including its chromosomes, and separates into two identical daughter cells during mitosis.

Option C: - When a parent cell divides into two or more daughter cells, the process is known as cell division.Every cell reproduces by dividing into two, with each parent cell producing two daughter cells.

Option D: - A concept of binary fission that happens in plasmodium.

Final Answer: - In spirogyra asexual reproduction takes place by breaking filaments into smaller bits.