With reference to asexual reproduction in simple organisms, consider the following statements: 1. Yeast reproduces by a process called fragmentation. 2. Algae multiply rapidly by fragmentation when water and nutrients are available. 3. A yeast cell reproduces primarily through the formation of spores. Which of the statements given above is/are correct?

The correct option is (b) 2 only. Explanation Asexual reproduction involves the production of new individuals from a single parent without the involvement of gamete fusion. Different simple organisms utilize specific mechanisms such as budding, fragmentation, and spore formation based on their cellular structure. - Statement 1 is Incorrect: Yeast is a unicellular organism that reproduces primarily through a process called budding. During this process, a small bulb-like projection (bud) emerges from the parent cell, grows, and eventually detaches to form a new independent cell. Fragmentation is typically observed in multicellular organisms with simple body designs. - Statement 2 is Correct: Algae, such as Spirogyra, reproduce by fragmentation. When environmental conditions are favorable (abundant water and nutrients), the algae grow rapidly and break into two or more fragments. Each fragment subsequently grows into a new individual. - Statement 3 is Incorrect: The primary mode of asexual reproduction in yeast is budding, not spore formation. Spore formation is the characteristic method of asexual reproduction in fungi like bread mould (Rhizopus) and lower plants like mosses and ferns. While yeast may form spores under specific stress conditions or during sexual reproduction, budding is the standard asexual method. Key Takeaway: Yeast reproduces via budding, whereas filamentous algae (like Spirogyra) reproduce via fragmentation. Spore formation is the primary asexual method for bread mould.

With reference to asexual reproduction in simple o... - NCERT Class 7 Science MCQ

Solution

The correct option is (b) 2 only.

Explanation

Asexual reproduction involves the production of new individuals from a single parent without the involvement of gamete fusion. Different simple organisms utilize specific mechanisms such as budding, fragmentation, and spore formation based on their cellular structure.

Statement 1 is Incorrect: Yeast is a unicellular organism that reproduces primarily through a process called budding. During this process, a small bulb-like projection (bud) emerges from the parent cell, grows, and eventually detaches to form a new independent cell. Fragmentation is typically observed in multicellular organisms with simple body designs.
Statement 2 is Correct: Algae, such as Spirogyra, reproduce by fragmentation. When environmental conditions are favorable (abundant water and nutrients), the algae grow rapidly and break into two or more fragments. Each fragment subsequently grows into a new individual.
Statement 3 is Incorrect: The primary mode of asexual reproduction in yeast is budding, not spore formation. Spore formation is the characteristic method of asexual reproduction in fungi like bread mould (Rhizopus) and lower plants like mosses and ferns. While yeast may form spores under specific stress conditions or during sexual reproduction, budding is the standard asexual method.

Key Takeaway: Yeast reproduces via budding, whereas filamentous algae (like Spirogyra) reproduce via fragmentation. Spore formation is the primary asexual method for bread mould.

NCERT Class 7 Science — Chapter 4: Reproduction in plants

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