Biology - Osmosis/ Diffusion

To define a selectively permeable membrane

allows some but not all substances to pass through.

To state the advantages of a selectively permeable membrane

Only certain substances are let in or out of cell.

List three components of a cell that have selectively permeable membranes

cell membrane, chloroplast membrane, mitochondria membrane

To define diffusion

movement of molecules from high concentration to low concentration

To explain why diffusion is a passive process

doesn't require energy

To describe how diffusion of oxygen occurs between the lungs and blood

Oxygen diffuses from the alveoli (lungs) into the capillary.

Carbon dioxide and water vapour diffuses from capillary into the alveoli (lungs).

To describe how diffusion of carbon dioxide occurs between atmosphere and leaf

Carbon dioxide diffuses from the atmosphere and into the leaf through the stomata.

Oxygen diffuses from the leaf into the atmosphere.

To define osmosis

movement of water from a region of high water concentration to a region of low water concentration through a semi permeable membrane

To describe why osmosis is a special type of diffusion

only includes the movement of water only from a high to a low water concentration across a semi permeable membrane.

To list two examples of how osmosis helps with the preservation of food

salting meat, sugar in jam

To describe how osmosis helps with the preservation of food.

causes the micro-organisms (Bacteria) on the meat to lose water and die due to osmosis.

To describe if water enters or leaves an animal cell living in a higher water concentration (lower solute concentration)

Animal cell will gain water due to osmosis.

To describe what happens an animal cell if too much water enters animal cell

cell will enlarge, burst and die.

To describe the role of the contractile vacuole in the amoeba that lives in fresh water environments

expels excess water

To describe if water enters or leaves an animal cell living in a lower water concentration (higher solute concentration)

will lose water due to

osmosis.

To describe what happens an animal cell if too little water enters animal cell

shrivel and maybe die

To state the process of how water enters the root hairs of a plant

water moves into cell by osmosis

To describe if water enters or leaves a plant cell living in a higher water concentration (lower solute concentration)

Water moves into cell

To define turgor pressure

when there is pressure of the cytoplasm and vacuole against the cell wall of a plant.

To state the importance of turgor pressure for plant cells

gives the plant strength and support.

To describe the appearance of plant cells when they lose turgor pressure

wilt