Active transport

p.216

Requirements

• Show me boards pens and rubbers

Objectives

• Students should learn:• that active transport is the absorption of

substances against a concentration gradient• that energy from respiration is needed to carry

out active transport• that active transport enables cells to take up

ions from very dilute solutions• that sugars and ions can pass through cell

membranes.

Outcomes

• Most students should be able to:• describe how active transport occurs• state examples of active transport in plants and

animals• explain the importance of active transport to

plants and animals.• Some students should also be able to:• explain in detail how active transport across a

cell membrane takes place.

Specification

• Substances are sometimes absorbed against a concentration gradient. This requires the use of energy from respiration. The process is called active transport. Active transport enables cells to absorb ions from very dilute solutions. [B3.1.1 g)]

Workbook

• P.107

Active transport animation

• Old nelson thornes disc b3 1.1 active transport simulation

Model

Describe the mechanism for active transport

Compare and contrast diffusion, osmosis and active transport

AQA Science © Nelson Thornes Ltd 2006 9

Active transport

Q1 p.217Diffusion, osmosis, concentration, against, transport, energy, respiration

1

2

3

4

5

6

How?

Draw and label from p. 216

AQA Science © Nelson Thornes Ltd 2006 11

• It takes energy for the active transport system to carry a molecule across the membrane and then return to its original position.

• The energy comes from cellular respiration.

• The rate of cellular respiration and the rate of active transport are closely linked.

• What adaptation would cells doing lots of active transport have?

• Cells involved usually have lots of mitochondria to provide the energy they need.

Uses of active transport

• Plants • Animals

Uses of active transport

• Plants• Moving ions into their

roots

• Animals • Cells lining the gut use

active transport to move digested products in

• Cells in the kidney take glucose back from filtered blood

• Crocodiles move salt out into glands so they can live in the sea

Extension

• Did you know p. 217• Cystic fibrosis

Label the graph: “Which line is which?”U

ptak

e of

K+ i

ons

by p

lant

root

(uni

ts)

ATP

conc

entr

ation

in th

e ce

lls

Time (mins)

A

B

C

D

• Uptake in roots + oxygen• Uptake by roots + Argon• ATP concentration in roots + Oxygen• ATP concentration in roots + Argon

Key

Hungry hipposwhy is this like active transport?

• http://www.youtube.com/watch?v=8HPI_HT6yjo

White board activityanswer D or O or AT

• She could smell his aftershave from a few metres away. • Root hairs taking up water from the soil. • Oxygen moving between the alveoli and the bloodstream.• Glucose in the intestine moving into the blood in the villi

down a concentration gradient. • Nitrate ions being taken into the root hair against a

concentration gradient. • Glucose moving into the blood from a kidney tubule with

a very low glucose concentration.• Water being lost from a cell as neighbouring cells lose

water.