1.1.1 - The Need For A Circulatory System

Question 1

What Do The Cells Of All Living Organisms Need A Constant Supply Of?
(2 Points)

Answer 1

~ Reactants for metabolism.
~ E.g. Oxygen and glucose.

Question 2

How Do Single Celled Organisms Gain Oxygen & Glucose?

Answer 2

Directly from their surroundings and the molecules can diffuse to all parts of the cell quickly due to a short diffusion distance.

Question 3

How Do Larger Organisms Gain Oxygen & Glucose?
(3 Points)

Answer 3

~ They are made up of many layers.
~ The time taken for substances to diffuse to every cell in the body would be too long.
~ Larger organisms have higher diffusion distances and energy requirements, this means the delivery of reactants for metabolism needs to happen quickly.

Question 4

What Is Mass Transport?

Answer 4

The bulk movement for gases or liquids in one direction, usually via a system of vessels and tubes.

Question 5

What Do Mass Transport Systems Help To Do?
(3 Points)

Answer 5

~ Bring substances quickly from one exchange site to another.
~ Maintain diffusion gradients at exchange sites and between cells and their fluid surroundings.
~ Ensure effective cell activity by supplying reactants and removing waste products.