1. Transport

1.1 The Importance Of Having A Transport System In Some Multicellular Organism

Why it is important to have a transport system in some multicellular organism?

For the exchange of substances such as nutrients, waste products and respiratory gases with the environment

Occur through simple diffusion

Exchange of substances between the organism and its environment depends on

1. Surface area – the larger the better

2. Volume – the smaller the better

3. Total surface area/volume - the larger the better

4. Distance – the nearest the better

5. Concentration gradient – the higher the better

Total surface area/volume

The smaller the size the larger the total surface area/volume.

The larger the total surface area/volume the better the exchange of substances between the organism and the environment

How multicellular organisms transport substances?

Simple diffusion alone cannot supply oxygen and nutrient for larger multicellular organism

Cells are situated far away from the external environment

Need a circulatory system to transport substances throughout the body

Exercise

1. Why it is important to have a transport system in some multicellular organism?

2. Give two factors that effect the exchange of substances between the organism and the environment.

3. How multicellular organisms transport substances?

4. Explain why unicellular organisms do not have the same problems as the multicellular organisms.

Answer

answer Exercise 1.doc