The process whose specific outcome is the progression of the pollen grain over time, from its formation to the mature structure. The process begins with the meiosis of the microsporocyte to form four haploid microspores. The nucleus of each microspore then divides by mitosis to form a two-celled organism, the pollen grain, that contains a tube cell as well as a smaller generative cell. The pollen grain is surrounded by an elaborate cell wall. In some species, the generative cell immediately divides again to give a pair of sperm cells. In most flowering plants, however this division takes place later, in the tube that develops when a pollen grain germinates.

The process whose specific outcome is the progression of the embryo sac over time, from its formation as the megaspore to the mature structure. The process begins when three of the four haploid megaspores disintegrate, and the fourth undergoes mitosis giving rise to a binucleate syncytial embryo sac. The two haploid nuclei migrate to the opposite poles of the embryo sac and then undergo two rounds of mitosis generating four haploid nuclei at each pole. One nucleus from each set of four migrates to the center of the cell. Cellularization occurs, resulting in an eight-nucleate seven-celled structure. This structure contains two synergid cells and an egg cell at the micropylar end, and three antipodal cells at the other end. A binucleate endosperm mother cell is formed at the center.

The cellular chemical reactions and pathways involving RNA, ribonucleic acid, one of the two main type of nucleic acid, consisting of a long, unbranched macromolecule formed from ribonucleotides joined in 3',5'-phosphodiester linkage.

A semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration.