Diffusion and Osmosis

Definition of Osmosis

movement of a solvent (as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane

Importance of osmosis

otherwise water is unable to move in or out of cells. Without water the cells will die and if water can't pass than they could get to saturated and burst.

Examples of Diffusiom

A teabag placed in a cup of hot water will diffuse into the water. Cigarette smoke diffuses into the air. Stirring some sugar into tea will help it diffuse quicker.

Why is active transport important

Active transport is important for cellular function because it moves important items, such as calcium and glucose, into and out of cells.

Why does active transport require ATP?

Active transport requires energy because it is pumping particles, such as proteins, ions and sugar molecules, against a concentration gradient

Importance of Diffusion

Diffusion is important to organisms because it is the process by which useful molecules enter the body cells and waste products are removed.

Define Diffusion

Diffusion is the action of molecules moving from an area of high concentration to an area of lower concentration.

Passive transport

Does not require cellular energy. Moves molecules down. High to low.

Which direction do the molecules move on the concentration gradient? (Diffusion)

Down

How does osmosis occur in cells

It helps to move water in and out of cells

Function of the membrane as a whole

It only lets certain things in and by doing do protects the cell

Why is the cell membrane important to the cell?

It protects the cell from its surroundings.

Is diffusion Passive or active?

Passive

Examples of Osmosis

Plant roots to take in water Cell memebrane to get water. Fingers pruning when submerged in water.

What is the cell membrane composed of?

The cell membrane is comprised of phospholipids and proteins

Isotonic

The concentration of solutes is equal on both sides of the cell.

Hypotonic solution

The concentration of solutes is greater inside the cell than outside the cell. Cells may swell and burst.

Hypertonic

The concentration of solutes is greater outside the cell than inside the cell. Cells may skrink.

Active transport

Uses ATP to pump molecules against/up the concentration gradient. Low to high.