Correct Option
The correct option is Budding.
Explanation
Asexual reproduction in unicellular organisms involves the production of offspring from a single parent without the fusion of gametes. In yeast, a unicellular fungus, the primary mode of reproduction involves unequal division leading to the formation of a distinct outgrowth.
Option Analysis
- Budding: Budding (Correct)
In yeast, the cell division is unequal and a small bud (outgrowth) is produced that remains attached initially to the parent cell. The nucleus divides, and one part moves into the bud. Eventually, the bud separates from the parent cell and matures into a new yeast organism. This fits the description of a "small outgrowth." - Fragmentation: Fragmentation (Incorrect)
Fragmentation is a mode of asexual reproduction observed in multicellular organisms with relatively simple body organization, such as the algae Spirogyra. The body breaks up into smaller pieces (fragments) upon maturation, each growing into a new individual. It is not characteristic of unicellular yeast. - Binary fission: Binary Fission (Incorrect)
Binary fission involves the division of a parent cell into two nearly equal-sized daughter cells. This is characteristic of organisms like Amoeba and bacteria. Yeast division is distinct because it is unequal (parent and bud are different sizes). - Spore formation: Spore Formation (Incorrect)
Spore formation is common in multicellular fungi like Rhizopus (bread mould), where reproductive structures called sporangia produce spores. While yeast can form spores under specific stress conditions (often linked to sexual processes), the characteristic asexual method involving an outgrowth is budding.
Key Takeaway
Budding is the characteristic mode of asexual reproduction in yeast, distinguished by unequal cell division and the formation of a small outgrowth that eventually detaches.