Biology - Osmosis and Tonicity Guided Notes

Biology Osmosis and Tonicity Guided Notes study

What is passive transport?

Passive transport is the movement of molecules from a high concentration to a low concentration without the use of energy.

What are the two types of diffusion?

Two types of diffusion are facilitated diffusion and simple diffusion.

Does diffusion require energy?

Diffusion does NOT require energy.

The diffusion of water through a selectively permeable membrane is called

osmosis

Like other forms of diffusion, osmosis involves the movement of this substance

water

Osmosis is a type of

passive transport

In osmosis, water follows this

water follows solute

The movement of water depends on the

concentration of free water molecules in the cytoplasm and the fluid outside of the cell. 

How many possible direction can the water move?

Three

The possible directions the water can move in are:

Water moves out, Water moves in, No net water movement, meaning equal amount of solute.

Water moves from a

high concentration of water to a low concentration of water

Because the membrane may be impermeable to some solutes,

 osmosis can change the volume of fluid inside a cell

This is the ability of a solution to affect the fluid volume and pressure in a cell

Tonicity

Hyper =

Higher

When water diffuses out of the cell, the cell

shrinks/shrivels

A solution that causes a cell to shrink due to osmosis is a

hypertonic solution

More solute outside the cell

Hypertonic

Hypo =

Lower

In a hypotonic solution, water

moves in

When water diffuses into the cell,

the cell swells

A solution that causes a cell to swell because of osmosis is called a

hypotonic solution

Cell swells-

could burst

Less solute outside the cell

Hypotonic

Iso=

Equal

Diffusion

The movement of a small molecule down a concentration gradient

A solution that produces no change in cell volume because of osmosis is called an

isotonic solution

Equal solute inside and outside the cell

Isotonic