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.
In mosses, the gametophyte is the dominant generation, while the sporophytes consist of sporangium-bearing stalks growing from the tips of the gametophytes. A sporophyte (/spÉËroÊËfaÉªt/) is the diploid multicellular stage in the life cycle of a plant or alga.n flowering plants the gametophytes are very reduced in size, and are represented by the pollen and the embryo sac. The sporophyte produces spores (hence the name) by meiosis, a process also known as reduction division that reduces the number of chromosomes in each spore mother cell by half.