When a nerve impulse is triggered, sodium and potassium pass through the cell membrane along the concentration gradient. To return the concentration gradient to its initial state, the membrane protein must continually pump sodium out of the cell and bring potassium into the cell. This requires energy from the cell.ransport that is âactiveâ is different in that it requires the energy of certain membrane proteins to get across the concentration gradient and either into or out of the cell.
Spores are haploid reproductive cells. Remember, a sporophyte is a diploid organism, so in order to produce haploid cells with half the number of chromosomes, meiosis must occur. Meiosis is a type of cell division that cuts the number of chromosomes in a cell in half. In sporophytes, it occurs in structures called sporangia (sporangium is singular). Once spores are produced in a sporangium, they are often released into the air. A single haploid spore will undergo mitosis, or cell division without a reduction in chromosome number, to become a multicellular haploid gametophyte.
Pine gametophyte (outside) surrounding the embryo (inside). A gametophyte is the haploid multicellular stage in the alternation of generations life cycle of plants and algae. It develops from a spore by mitotic cell division. Spores are the products of meiosis in sporophytes.Gametophytes produce haploid gametes by mitosis.he fusion of male and female gametes produces a diploid zygote, which develops by repeated mitotic cell divisions into a multicellular sporophyte. In bryophytes (mosses, liverworts, and hornworts), the gametophyte represents the longer lived, nutritionally independent and more visible stage of the life cycle.