Osmosis

Front 1

Diffusion

Back 1

The movement of molecules from a reigon of high concentration to a reigon of low concentration

Front 2

What is a passive process?

Back 2

A process which requires no energy to occur

Front 3

What is the opposite of diffusion?

Back 3

Going against the concentration gradient; when molecules move from a reigon of low concentration to a reigon of high concentration.

Front 4

Active transport

Back 4

When energy is needed to transport (often large) molecules across the cell membrane with the use of enzymes.

Front 5

When do plant root hair cells use active transport?

Back 5

To move minerals from the soil into the roots. The concentration of minerals is higher in the roots than in the soil so molecules are needed to move against the concentration gradient

Front 6

Why does a slug die if you cover it with salt?

Back 6

The water concentration in the cells of the slug is higher than the water concentration in the salt. Through osmosis, the water travels from the slug into the salt through the cell membrane of each cell. With so much water leaving the slug, the cells cannot carry out vital reactions for life and the slug dies.

Front 7

Osmosis

Back 7

A type of diffusion;

- the movement of water from a reigon of high water concentration to a reigon of lower water concentration through a partially permeable membrane

Front 8

Partially permeable membrane

Back 8

A membrane which lets smaller molecules pass through it (e.g; water) but not bigger molecules (e.g; salt, glucose)

Front 9

Are all cell membranes partially permiable?

Back 9

Yes

Front 10

Root hairs

Back 10

The tiny projections that cover the region of the roots just behind the growing tip

Front 11

How do root hairs aid osmosis?

Back 11

They increase surface area, maximising water uptake

Front 12

Why do root hair cells use osmosis?

Back 12

Because the conentration of the water is higher in the soil than in the cytoplasm of the root hair cells.

Front 13

Under what circumstances would osmosis come to a halt?

Back 13

When the concentration of water is the same on both sides of a partially permiable membrane

Front 14

Why is it important that water is constantly moved away from the roots and into the rest of the plant?

Back 14

If the water concentration in the cytoplasm is the same as that of the soil, then osmosis will stop and the plant will not be able to intake anymore water.

Front 15

Give a test for osmosis

Back 15

- Raw potato cylinders are weighed, placed in differing concentrations of salt solutions, left for a while, then weighed again so their change in mass is recorded.

- The reason for the change of mass in the potatos is because of osmosis.

Front 16

Why do raw potato cylinders have a greater mass after being left in a weak salt solution?

Back 16

Through osmosis, water in the solution is moved into the potato cells via the membrane. The added water increases the overall mass. This is because the concentration of water is initially higher in the solution.

Front 17

Why do raw potato cylinders have a smaller mass after being left in a strong salt solution?

Back 17

Through osmosis, water in the potato cells is moved into the solution via the cell membranes of the potato cells. The loss of water decreases the overall mass.

This is because the concentration of water is initially higher in the potato cells.

Front 18

Under what circumstances would the mass of a raw potato cylinder stay the same after being left in a salt solution?

Back 18

If the water concentration in the solution is the same as in the potato cells, then the Net movement of water molecules will be zero and osmosis will not take place. This leaves the mass of the potato cylinder unchanged.