AP BIOLOGY

Detailed explanation-1: -Pollen itself is not a male gamete. Each pollen grain contains vegetative germ cells, that is, non-germ cells and one germ cell or germ cell. In flowering plants, vegetative cells produce pollen tubes, which divide to form two sperm nuclei.

Detailed explanation-2: -There is no sperm present in a pollen grain. A pollen grain is a tiny male plant, a male gametophyte (gamete-forming plant). He is a multicellular organism (usually two cells in flowering plants, but more in the case of gymnosperm pollen) capable of producing sperm if he gets an opportunity.

Detailed explanation-3: -The sperm cells of a flowering plant are contained in pollen grains. Pollination occurs when pollen grains are transported from anthers to stigmas. This action starts fertil-ization, as shown in Figure 1. After the pollen lands on the stigma, a tube grows from the pollen grain through the style to the ovary.

Detailed explanation-4: -The two sperm cells arise from the generative pollen cell either within the pollen grain or after germination inside the pollen tube.

Detailed explanation-5: -Answer and Explanation: Pollen grains are made of two main cells: the tube cell and the generative cell. The generative cell is the cell that eventually produces the sperm nuclei.