3.7 Active Transport

Question 1

What is active transport?

Answer 1

The movement of particles across a membrane against a concentration gradient (i.e. from an area of lower to an area of higher concentration) using energy transferred during respiration

Question 2

What is responsible for the energy needed in active transport?

Answer 2

Cellular respiration that takes place in the cells mitochondria. It stores the energy that breaks down glucose to release energy in chemical stores called ATP

Question 3

How do root hair cells take in water?

Answer 3

There’s usually a higher concentration of water in the soil than there is inside the plant, so the water is drawn into the root hair cell across the partially permeable cell membrane by osmosis

Question 4

How do root hair cells take in mineral ions?

Answer 4

Plants need nitrogen to make proteins. They get nitrogen from nitrate ions, these mineral ions move into root hair cells by active transport, since the concentration of mineral ions in the root hair cells is usually higher than in the soil. The cells use molecules of ATP to provide energy to actively transport the ions through the cell membrane

Question 5

Why can’t plants absorb mineral ions by diffusion?

Answer 5

Their concentration is higher in the cell than in the soil

Question 6

How are root hair cells adapted to take in as much mineral ions and water molecules as possible? (3)

Answer 6

• The cells on plant roots grow into long ‘hairs’ which stick out into the soil
• Each branch of a root will be covered in millions of these microscopic hairs
• This gives the plant a big surface area for absorbing water and mineral ions from the soil

Question 7

What do plants need nitrogen for?

Answer 7

Making proteins

Question 8

What do the root hair cells use to provide energy to actively transport mineral ions through the cell membrane?

Answer 8

Molecules of ATP