active transport

Question 1

define active transport

Answer 1

the movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration against the concentration gradient

Question 2

what two things does active transport require

Answer 2

• carrier proteins (each carrier protein being specific for a particular type of molecule or ion)
• energy - make the carrier proteins change shape, allowing it to transfer the molecules or ions across the cell membrane

Question 3

where is the energy coming from

Answer 3

• provided by ATP
• produced during respiration
• ATP is hydrolysed to release energy

Question 4

what is active transport important in

Answer 4

• the reabsorption of useful molecules and ions into the blood after filtration into the kidney tubules
• the absorption of some products of digestion from the digestive tract
• the loading of sugar from the photosynthesising cells of leaves into the phloem tissue for transport around the plant
• the loading of inorganic ions from the soil into root hairs