2.2 Oxygen and diffusion

Question 1

What is the relationship between the volume of an organism and its oxygen requirement?

Answer 1

The volume of oxygen required is proportional to its volume

Therefore an amoeba will require less oxygen than an elephant!

Question 2

What is the relationship between the surface area of an organism and the rate of absorption of oxygen?

Answer 2

The rate of absorption of oxygen is proportional to the surface area

Therefore rate of absorption of oxygen is increased if the surface area is increased

Question 3

How does the surface area:volume ratio change as an organism gets larger

Answer 3

The surface area:volume ratio decreases

Question 4

define gas exchange

Answer 4

process by which gases cross a respiratory surface

Question 5

define respiration

Answer 5

the release of chemical energy (in the form of ATP) from food molecules

Question 6

Define Ventilation

Answer 6

bringing gases in and out of a respiratory surface so gas exchange can take place

Question 7

define diffusion

Answer 7

the net movement of a molecule down a concentration gradient, so that equlibrium is reached.