Biology B3 Exchange

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  • Created by: Jordan
  • Created on: 01-02-11 16:33

Exchange

Diffusion

Definition - Movement of particles from an area of high concentration to an area of low concentration

Efficiency of diffusion is increased if there is :

  • A large surface area over which exchange can take place
  • A concentration gradient without which nothing will diffuse
  • A thin surface area across which gas can diffuse

Osmosis

Definition - movement of water particles from an area of high concentration to an area of low concentration through a partially permeable membrane

Active Transport

Definition - movement of chemicals across the cell membrane against the concentration gradient.

There are times when cells need to move chemicals across the cell membrane against the concentration gradient.

This then requires energy, this comes from respiration, as the chemicals need to be pumped across the cell membrane.

Active transport enables cells to absorb

Comments

Swallowtail

This resource covers some of the facts needed for the understanding of gaseous exchange and absorption of digested food. There are clear diagrams with labels from which a student could learn some of the key details needed.

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