Gas Exchange

Question 1

How does alveoli work?

Answer 1

They are surrounded by a network of blood capillaries

Gasses diffuse into and out of the blood based on the concentration gradients

Question 2

How is a leaf adapted to a gas exchange?

Answer 2

-Broad so large surface area for diffusion
- thin so short diffusion distance
-air spaces allow gases to easily move to all cells
-lots of stomata
-plant can control the opening and the closing of stomata using the guard cells

Question 3

Where does gas exchange occurs in the leaves?

Answer 3

Stomata

Question 4

How does gases move in gas exchange?

Answer 4

By diffusion, from an area of high concentration to low concentration

Question 5

How long does respiration occur in plants?

Answer 5

24 hours a day

Question 6

When does photosynthesis occur?

Answer 6

Only when sunlight is available

Question 7

Explain how alveoli are adapted for gas exchange

Answer 7

1. Large surface area- for diffusion
2. Moist-to help dissolve gases and increase diffusion rate
3. Rich blood supply- to maintain steep diffusion gradient between alveoli and the blood
4. Thin cell walls-short diffusion distance, high increase diffusion rate

Question 8

Percentage of inhaled gases

Answer 8

Oxygen-20%
Carbon dioxide-0.04%
Nitrogen-78%
Other gases-1%

Question 9

Percentage of exhaled gases

Answer 9

Oxygen-16%
Carbon dioxide-4%
Nitrogen-78%
Other gases-1%

Question 10

Leaf adaptation for gas exchange

Answer 10

-lots of stomata
-plant can control the opening and closing of stomata using the guard cells
- large surface area for diffusion
-thin so short diffusion distance

Question 11

What is the levels of organisation within organisms?

Answer 11

Organelles
Cells
Tissues
Organs
Organ systems