B1.10 Exchanging materials

Question 1

Whats the relationship between an organism’s size and its surface area to volume ratio

Answer 1

The larger the organism, the lower the surface area to volume ratio will be

Question 2

What factors increase the effectiveness of a exchange surface

Answer 2

1. Large SA
2. Thin membrane
3. Efficient blood supply
4. In animals, being ventilated as it maintains a steep concentration gradient

Question 2

How does the SA:V affect the transport of molecules

Answer 2

• The lower the ratio, the farther the distance molecules need to travel to reach all parts of the organism
• If the distance is to high, then diffusion alone is not sufficient to transport molecules quickly enough

Question 3

What is alveoli

Answer 3

Tiny air sacs in the lungs where gas exchange occurs through diffusion. Oxygen from inhaled air moves into the blood, and carbon dioxide from the blood moves into the alveoli to be exhaled.

Question 4

How is alveoli adapted for its function

Answer 4

1. A large surface area
2. Thin walls
3. A good blood supply
4. Good ventilation to allow for efficient and rapid gas exchange.

Question 5

What is a stomata

Answer 5

Tiny pores on the leaf surface, that are surrounded by guard cells. They are crucial for controlling gas exchange and water vapor in and out of the leaf.