Movement of Substances

Question 1

Define the term diffusion

Answer 1

Movement of molecules from a region of high concentration to a region of lower concentration, down a concentration gradient (passive so does not need energy)

Question 2

Define the term osmosis

Answer 2

Movement of water molecules across a partially permeable membrane, from a region of higher water concentration to a region of lower water concentration (or down a water potential gradient)

Question 3

Define the term active transport

Answer 3

Movement of molecules/ions (e.g. glucose) against a concentration gradient, from a region of lower concentration to a region of higher concentration. Requires ATP/energy from respiration

Question 4

State four factors that affect the rate of movement of substances into and out of cells

Answer 4

Surface area:volume ratio, temperature, distance, concentration gradient

Question 5

When potato cylinders are placed in glucose solution, will water move into or out of the cells?

Answer 5

Out of cells by OSMOSIS

Question 6

When animal cells are placed in water (e.g. red blood cells),

Answer 6

Into cells by osmosis; cells burst as they have no cell walls