SPM Biology 10 Transport (Part 1)

SPM Biology 10 Transport

Transport system of human

The Importance of transport system in multicellular organisms

1. All the chemical reaction take place in the cells to ensure the survival of the cells.

2. Hence, every cell in an organism must be able to obtain all the substances it needs (nutrients, oxygen, etc.).

3. Besides, the cell must be able to remove the waster products such as carbon dioxide and urea from the cell.

4. Exchange of gases and substances occur across the plasma membrane of the cells by diffusion.

5. Unicellular organisms (Amoeba sp., etc.) can easily and rapidly obtain the cell requirements and removing the waster products by diffusion, without having any special structure to transport these substance. WHY? Because they:

• Small in size.
• Have a large total surface area to volume (TSA/V) ratio.

6. The smaller the size of the object, the larger the TSA/V ratio, the higher the rate of diffusion.

Surface-to-volume ratio

7. Multicellular organisms cannot depend on diffusion alone to gain the cell requirements. WHY? Because they:

• Large body size.
• Have a small TSA/V ratio.
• The amount of cell requirements and metabolic waster products increases.
• The cells are located further in the body.

8. To overcome these problem, multicellular organisms (human, animals, etc.) need special transport system:

• to transport the nutrients to all the body cells.
• to remove the metabolic waster products from the body cells.

9. The transport system in humans and animals = circulatory system.

10. In plants, the transport system is the vascular tissues which consist of xylem tissues and phloem tissues.