cell -- Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintenance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.

cell membrane -- The outer membrane of a cell, which separates it from the environment. Also called a plasma membrane.

cell wall -- Rigid structure deposited outside the cell membrane. Plants are known for their cell walls of cellulose.

chloroplast -- A chlorophyll found in green plant cells.

cytoplasm -- All the contents of a cell, including the plasma membrane,but not including the nucleus.

endoplasmic reticulum -- (ER) network of membranes in eukaryotic cells which helps in control of protein synthesis and cellular organization.

Golgi apparatus -- Eukaryotic organelle which package cell products, such as enzymes and hormones, and coordinate their transport to the outside of the cell.

membrane -- In biology, a boundary layer inside or around a living cell or tissue.

mitochondrion -- Complex organelle found in most eukaryotes; believed to be descended from free-living bacteria that established a symbiotic relationship with a primitive eukaryote. Mitochondria are the site of most of the energy production in most eukaryotes; they require oxygen to function.

multicellular -- Any organism which is composed of many cells is termed multicellular.

nucleus -- Membrane-bound organelle which contains the DNA in the form of chromosomes. It is the site of DNA replication, and the site of RNA synthesis.

plasma membrane -- Outer membrane of a cell, sometimes called the cell membrane. The term plasma membrane is used more frequently when discussing prokaryotes.

ribosome -- (ribosomal RNA)

vacuole -- Membrane-bound fluid-filled space within a cell. In most plant cells, there is a single large vacuole filling most of the cell's volume. Some bacterial cells contain gas vacuoles.

Concentration the amount of something in a given area or volume

Diffusion: the movement of a substance from an area of high concentration to an area of lower concentration until an equilibrium is reached.

Distilled water pure water, no solutes or elements

Hypertonic : concerning osmosis, a term used to compare one solution with another, a hypertonic solution has a higher concentration of solutes, when separated by a membrane that is permeable to the solvent and impermeable

to the solute. In this instance the solvent will flow from the region of lower solute concentration (hypotonic) to the region of higher concentration (hypertonic) by the process of osmosis. e.g. most fresh water protists are hypertonic when compared with their environment.

Hypotonic : a solution that has a lower concentration of solutes than a hypertonic one.

Isotonic : when two solutions separated by a membrane permeable to the solvent but not the solutes are of equal concentration this results in no net movement of solvent across the membrane.

Osmosis : the phenomenon whereby water flows across a selectively permeable membrane from a hypotonic environment to a hypertonic environment.

selectively permeable : applies to membranes which allow one substance to pass, but impede another. (You need to establish what the membrane is and isn't permeable to, recognising that you are interested in the difference between "pass through easily" and "hardly ever get past".)

solvent : a substance that is capable of dissolving another substance

solute : a substance that is capable of being dissolved by a solvent

Turgid : means firm, the opposite of flaccid, cells with wall become firm as a result of the uptake of water by osmosis,

Turgor : (pressure) the force exerted on a cell wall by a cell membrane as a result of osmotic uptake of water.

active transport : the movement of a substance across a cell membrane against its concentration gradient, which requires energy from the cell

passive transport: a form of transport which requires no energy from the organism, i.e. diffusion of a substance from an area of high concentration to one of a lower one.