Question

Name the cells of mature pollen grain when you observe under microscope with the following characters respectively,
A) Bigger cell with abundant food reserve and large irregular shaped nucleus.
B) Small, dense cytoplasm with nucleus.

• A. Generative cell, Gametes
• B. Vegetative cell, Gametes
• C. Vegetative cell, Generative cell
• D. Generative cell, Vegetative cell

Hint:

In a mature pollen grain of angiosperms, the vegetative cell forms the pollen tube, while the generative cell divides to form two sperm cells for double fertilization.

Answer 1

The Correct Option is C

This question asks us to identify the cells of a mature pollen grain based on their characteristics when observed under a microscope. A mature pollen grain in angiosperms typically contains two cells at the time of release: the vegetative cell and the generative cell. Let’s analyze the given characteristics to determine which cell corresponds to each description. - A) Bigger cell with abundant food reserve and large irregular shaped nucleus In a mature pollen grain, the vegetative cell (also called the tube cell) is the larger of the two cells. It is responsible for forming the pollen tube after pollination, which delivers the male gametes to the ovule. The vegetative cell has a large amount of cytoplasm with abundant food reserves (such as starch or lipids) to support the growth of the pollen tube. Additionally, it contains a large, irregularly shaped nucleus, which is consistent with its role in controlling pollen tube growth rather than direct reproduction. Therefore, the description of a "bigger cell with abundant food reserve and large irregular shaped nucleus" matches the vegetative cell. - B) Small, dense cytoplasm with nucleus The generative cell in a mature pollen grain is the smaller of the two cells and is typically embedded within the cytoplasm of the vegetative cell. The generative cell is responsible for dividing to form two sperm cells (male gametes) either before or during pollen tube growth, depending on the plant species. It has a smaller volume, dense cytoplasm (due to its compact size), and a distinct nucleus, which will later divide to form the sperm nuclei. The generative cell’s role is reproductive, and its smaller size and dense cytoplasm align with the description of a "small, dense cytoplasm with nucleus." Therefore, this description matches the generative cell. Now, let’s match these cells to the descriptions: - A) Bigger cell with abundant food reserve and large irregular shaped nucleus → Vegetative cell - B) Small, dense cytoplasm with nucleus → Generative cell This corresponds to Vegetative cell (for A) and Generative cell (for B). Let’s evaluate the options: - Option 1: Generative cell, Gametes The generative cell is the smaller cell, not the bigger one, so it does not match A. Additionally, "Gametes" are not present in the mature pollen grain at the time of observation under a microscope; the generative cell divides later to form gametes (sperm cells). This option is incorrect. - Option 2: Vegetative cell, Gametes The vegetative cell matches A, which is correct. However, "Gametes" are not present in the mature pollen grain at this stage, as explained above. The smaller cell is the generative cell, not gametes. This option is incorrect. - Option 3: Vegetative cell, Generative cell The vegetative cell matches A (bigger cell with abundant food reserve and large irregular nucleus), and the generative cell matches B (small, dense cytoplasm with nucleus). This option is correct. - Option 4: Generative cell, Vegetative cell The generative cell is the smaller cell, not the bigger one, so it does not match A. The vegetative cell is the larger cell, not the smaller one, so it does not match B. This option is incorrect. Therefore, the correct answer is (3) Vegetative cell, Generative cell, which aligns with the characteristics of the cells in a mature pollen grain. Thus, the correct answer is Vegetative cell, Generative cell.

Answer 2

Name the cells of mature pollen grain when you observe under microscope with the following characters respectively,
A) Bigger cell with abundant food reserve and large irregular shaped nucleus.
B) Small, dense cytoplasm with nucleus.

Correct Answer: Vegetative cell, Generative cell

Explanation:
In a mature pollen grain, two distinct types of cells can be observed under the microscope based on their size, cytoplasmic content, and nuclear characteristics.

A) The Vegetative cell (also called the tube cell) is the larger cell. It contains abundant cytoplasm filled with food reserves, which provide the necessary nutrients for the growth of the pollen tube during fertilization. The nucleus of the vegetative cell is generally large and irregularly shaped. This cell plays a crucial role in pollen tube formation that guides the sperm cells to the ovule.

B) The Generative cell is smaller and has a dense cytoplasm with a clearly visible nucleus. It is generally enclosed within the vegetative cell in mature pollen grains. The generative cell undergoes mitosis to produce two sperm cells (male gametes), which are involved in double fertilization in flowering plants.

Thus, the two cells observed in the mature pollen grain are the vegetative cell (bigger, nutrient-rich) and the generative cell (smaller, dense cytoplasm). Understanding this distinction is important in studying plant reproduction and fertilization mechanisms.