Cells Part 4 (Cell Connections)

Equilibrium

• When molecules are equally spread out; equal amount on both sides of membrane.

• When molecules are concentrated on one side of the membrane.

• When molecules are in constant motion but not changing position.

• When molecules are actively transported across the membrane.

Cell membrane

• A rigid structure that provides support to the cell.

• The selectively permeable membrane surrounding the cytoplasm of a cell.

• A barrier that prevents all substances from entering the cell.

• The site of energy production in the cell.

Selectively permeable

• Only some molecules are able to pass through.

• All molecules can pass through freely.

• Only large molecules can pass through.

• Only small molecules can pass through.

Membrane diffusion

• Oxygen, carbon dioxide, waste, nutrients and odors.

• Proteins, carbohydrates, vitamins, and minerals.

• Water, salts, sugars, and fats.

• Hormones, enzymes, antibodies, and neurotransmitters.

Diffusion

• The process of molecules moving from low concentration to high concentration.

• The movement of molecules in a vacuum.

• When molecules move from high concentration to low concentration.

• The process of molecules remaining stationary.

Passive transport

• The movement of materials through a membrane without any input of energy.

• The active movement of materials requiring energy input.

• The process of engulfing materials into the cell.

• The movement of materials against their concentration gradient.

Osmosis

• The movement of WATER from a higher to lower concentration.

• The movement of SOLIDS from a lower to higher concentration.

• The movement of WATER from a lower to higher concentration.

• The movement of GASES from a higher to lower concentration.

Concentration

• The amount of a substance in a specific volume/space.

• The total mass of a substance in a mixture.

• The ratio of solute to solvent in a solution.

• The temperature at which a substance dissolves.