1. 3) Active transport

2. Active transport
Definition:
The process in which energy is used to move
the particles of a substance against a
concentration gradient from a region where
they are in lower concentration to a region
where they are in higher concentration.

3. Active transport
 Occurs only in living things (because living
things respire to obtain energy required in
active transport)
 Involved in the absorption of
a) dissolved mineral salts by the root hairs
b) glucose and amino acids by cells in the small
intestine of humans

4. Energy
High Low
concentration concentration

6. Summary
Chapter 3

7. partially permeable


8. Summary

9. Differences between Diffusion,
Osmosis and Active transport
Process Movement Condition Additional
of requirements
Diffusion Molecules/ High conc. Down a conc.
ions to low conc. gradient
Osmosis Water High water Across a partially
molecules potential to permeable
low water membrane
potential
Active Particles of Low conc. to Against a conc.
transport substances high conc. Gradient;
Energy required

10. Differences between Osmosis
and Diffusion
Diffusion Osmosis
1.Flow of either solute or solvent 1.It involves flow of solvent molecules in
molecules is in both directions. one direction.
2.No such membrane is required. 2.It requires partially permeable
3.It is a fast process. membrane.
4.Occurs in liquids as well as 3.It is a slow process .
gases 4.Occurs only in liquids.
5.Movements are over large 5.The movement is over a short distance
distances

11. Temperature & diffusion
 The higher the temperature of the solution, the
faster the rate of diffusion

12. Molecular Wt. and Diffusion
 The higher the molecular weight of the molecule,
the slower the rate of diffusion