Biology 30S

1. having less than the normal tone of tissue
3. transport of a substance across a cell membrane by diffusion; expenditure of energy is not required
6. the ingestion of a smaller cell or cell fragment, a microorganism, or foreign particles by means of the local enfolding of a cell's membrane
7. the movement of ions or molecules across a cellular membrane from a lower to a higher concentration, requiring the consumption of energy.
8. any of a group of fatty compounds, as lecithin, composed of phosphoric esters, and occurring in living cells.
9. a sterol, C 27 H 46 O, that occurs in all animal tissues, especially in the brain, spinal cord, and adipose tissue, functioning chiefly as a protective agent in the skin and myelin sheaths of nerve cells
11. a conceptual model of cell membrane and its boundary as a tightly packed double layer of phospholipid molecules
12. noting or pertaining to solutions characterized by equal osmotic pressure.

2. the gradual difference in concentration of a dissolved substance in a solution between a region of high density and one of lower density.
4. the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher
5. noting a solution of higher osmotic pressure than another solution with which it is compared (opposite to hypotonic)
10. the transport of fluid into a cell by means of local infoldings by the cell membrane so that a tiny vesicle or sac forms around each droplet