Selectively Permeable

1.

• Selectively Permeable – is a membrane that will allow specific substances such as molecules and ions to enter the membrane, but will prevent others from entering. Examples of selectively permeable membranes are animal cells, plant cells, plasma membranes and cell organelles.

• Solvent – is a dissolving agent such as water

• Solute – organic or inorganic molecules; dissolved materials/substances.

• Diffusion – is when substances are moved from cell to cell through a permeable membrane with the usage of ATP or energy. Substances of a high concentration will move to areas of lower concentration.

• Osmosis – is a type of diffusion that involves water through a selectively permeable membrane. The water moves from high to low concentration.

• Osmotically active substance – when there is an inequality of a substance outside and inside of the selectively permeable membrane, the water between the two sides will try to balance the amounts on both sides. A solution of salt water, the outside of the membrane may have more salt than the inside and the water inside the membrane will travel out.

• Hypotonic – solution is when the substance’s concentration is lower on one side of the membrane than the other.

• Hypertonic – solution is when the substance’s concentration is higher on one side of the membrane than the other.

• Isotonic – solution is when the substance’s concentration is the same on both sides of the membrane.

• Turgor pressure – in plant cells is caused by the cell wall and the protoplast the more hypertonic or hypotonic the solution that the cell is placed in will affect the shape of the cell. In a hypertonic solution the cell’s protoplast will shrink pulling away from the cell wall causing low turgor pressure, and in a hypotonic solution there is high pressure causing the protoplast to push against the cell wall.

• Osmolarity – is the term used for the amount of osmotically active substances, the...