Tuition Centre Singapore Biology Tuition – Movement of Substances (Diffusion)

Common Error 1

Diffusion of particles from one region to another takes place at a constant speed.

Correct Concept 1

The concentration gradient determines the speed of diffusion. As diffusion proceeds, the concentration gradient decreases. The speed of diffusion thus decreases as well

Common Error 2

During diffusion, particles only move in the direction of the region of lower concentration.

Correct Concept 2

Particles move randomly in all directions. The net movement of particles is in the direction of the region of lower concentration

Common Error 3

Each cell is a self-contained unit of life.

Correct Concept 3

Cells interact with other cells in a network of communication. There are many examples where substances, like carbon dioxide, diffuse through the leaf from cell to cell before exiting into the atmosphere

Please contact Mr Ong @ 9863 9633 or Angie @ 96790479 if you need help in O level Pure or combined Biology