Topic 1 - Cell Transport

Question 1

What is simple diffusion?

Answer 1

The net movement of molecules from an area of high concentration to an area of low concentration down a concentration gradient

Question 2

What molecules enter and leave cells via simple diffusion through the cell membrane?

Answer 2

Small molecules e.g. oxygen, water, glucose, amino acids

Question 3

What factors affect the rate of diffusion?

Answer 3

● Temperature - The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly
● Concentration gradient - The greater the difference in concentration, the quicker the rate of diffusion
● Surface area of cell membrane - The greater the surface area, the faster the rate of diffusion

Question 4

Define osmosis

Answer 4

The net movement of water molecules from
an area of high water concentration to an
area of low water concentration through a
partially permeable membrane

Question 5

What is active transport?

Answer 5

The movement of molecules across a cell membrane from an area of low concentration to an area of high concentration, against the
concentration gradient, using energy

Question 6

How is a percentage change in mass

calculated?

Answer 6

final mass - initial mass / initial mass … x 100