Diffusion/Osmosis/Active Transport

Question 1

What is diffusion essential in?

Answer 1

The exchange of respiratory gases, the absorption of dissolved food and the removal of waste products

Question 2

What is the purpose of diffusion?

Answer 2

Useful molecules enter and waste molecules leave

Question 3

What is osmosis?

Answer 3

Osmosis is the movement of water molecules from an area of higher water concentration to an area of lower water concentration through selectively permeable membrane. This is a passive process.

Question 4

What would the effect on cells be if the surrounding solution is of the same water concentration?

Answer 4

no loss or gain in mass, cell remains unchanged

Question 5

What would the effect on a plant cell be if the surrounding solution is of a higher water concentration?

Answer 5

gain mass, cell would become turgid

Question 6

What would the effect on a plant cell be if the surrounding solution is of a lower water concentration?

Answer 6

lose mass, cell would become plasmolysed

Question 7

What would the effect on an animal cell be if the surrounding solution is of a higher water concentration?

Answer 7

gains mass, the cell would burst (lacks cell wall)

Question 8

What would the effect on an animal cell be if the surrounding solution is of a lower water concentration?

Answer 8

loses mass, the cell would shrink

Question 9

What is active transport?

Answer 9

The movement of molecules and ions across the cell membrane - from a lower to higher concentration - against a concentration gradient. This is an active process and requires energy. This energy is supplied by ATP and formed during respiration. Protein molecules in the membrane act as carriers. They recognize specific molecules and ions, transfer them across the membrane