• Semi-permeable membrane: a cell membrane that allows some, but not all substances through

• Channel Proteins: Proteins in the membrane that allow passage of specific molecules through

• Carrier Proteins: Proteins in the membrane that change in shape and move specific molecules across that membrane, a form of active transport.

• Glyco-things: Carbohydrate chains that can attach to phospholipids or proteins

• Solute: Particles that dissolve

• Solvent: Liquid that does the dissolving

• Solution: mixture of solute and solvent

• Diffusion: When particles naturally move from areas of high concentration to areas of low concentration

• Concentration Gradient: When particles are not evenly distributed

• Passive Transport: a type of cell transport that does not require energy, and goes with the concentration gradient

• Simple Diffusion: Type of diffusion in which particles go through the membrane on their own

• Facilitated Diffusion: Type of diffusion in which particles pass through channel protein helpers.

• Osmosis: the movement of water across the membrane.

• Hypertonic: High solute concentration in solution

• Hypotonic: Low solute concentration in solution

• Isotonic: Same concentration of solute and water both inside and outside the cell.\

• Active Transport: Type of cell transport that uses ATP energy, and goes against the concentration gradient

• Molecular Pumps: Protein pumps that move molecules against the gradient from low to high concentration (ex: Sodium potassium pump)

• Endocytosis: The act of a cell engulfing a lot of stuff.

• Phagocytosis: A cell eating (ex: an amoeba engulfing a paramecium)

• Pinocytosis: A cell drinking (ex: saltwater single celled organisms need to engulf water to keep solutes balanced

• Exocytosis: The act of a cell excreting (spitting out) a lot of stuff. (Ex: Cells releasing many hormones/proteins at once

The plasma membrane separates the intracellular (inside the cell) environment from the extracellular (outside the cell) environment. The cell membrane structure is described as a fluid-mosaic model, with a phospholipid bilayer and random patterns of proteins in the membrane. The selectively permeable cell membrane allows some, but not all substances through, which helps maintain homeostasis.

The cell membrane consists of phospholipids, proteins, carbohydrate chains, and cholesterol.

Small, nonpolar molecules like oxygen and carbon dioxide can easily pass through the membrane. Small, polar molecules like water can pass through the membrane with special channel proteins. Large, nonpolar molecules like carbs and proteins cannot pass through the membrane. Charged molecules like ions cannot pass through the membrane. Particles that cannot pass through on their own need protein helpers in order to pass through the membrane.

Water will always move from where there is more water per area to where there is less water per area.

The cell will shrink and shrivel in a hypertonic solution. The cell will swell in a hypotonic solution.