Module: | Pre-fertilization: Micro/Megasporogenesis
Q5: Consider the following statements regarding megasporogenesis and embryonic development:
1. Megasporogenesis is defined as the process of formation of megaspores from the megaspore mother cell (MMC) via mitotic divisions.
2. In monosporic development, only one of the four megaspores remains functional while the other three degenerate.
3. The single functional megaspore ultimately develops into the female gametophyte, also known as the embryo sac.
Which of the above statements is/are correct?
2. In monosporic development, only one of the four megaspores remains functional while the other three degenerate.
3. The single functional megaspore ultimately develops into the female gametophyte, also known as the embryo sac.
Which of the above statements is/are correct?
✅ Correct Answer: B
The correct option is B. Statements 2 and 3 are correct, but Statement 1 is incorrect.
Megasporogenesis is the formation of megaspores from the diploid megaspore mother cell (MMC) exclusively through meiosis, not mitosis.
This meiotic division ensures the reduction of ploidy, resulting in a linear tetrad of four haploid megaspores.
Structurally and causally, most angiosperms favor efficiency and resource concentration; thus, the three micropylar megaspores degenerate, leaving only the chalazal megaspore functional.
This method of embryo sac formation from a single megaspore is termed monosporic development.
Historically, the concept of monosporic (Polygonum type) development is a staple in Class 12 board examinations, requiring students to link the initial meiotic reduction division with the subsequent free-nuclear mitotic divisions that build the female gametophyte.
Megasporogenesis is the formation of megaspores from the diploid megaspore mother cell (MMC) exclusively through meiosis, not mitosis.
This meiotic division ensures the reduction of ploidy, resulting in a linear tetrad of four haploid megaspores.
Structurally and causally, most angiosperms favor efficiency and resource concentration; thus, the three micropylar megaspores degenerate, leaving only the chalazal megaspore functional.
This method of embryo sac formation from a single megaspore is termed monosporic development.
Historically, the concept of monosporic (Polygonum type) development is a staple in Class 12 board examinations, requiring students to link the initial meiotic reduction division with the subsequent free-nuclear mitotic divisions that build the female gametophyte.