2g-Gas exchange

Question 1

Q: What is gas exchange and why is it essential for living organisms?

Answer 1

A: Gas exchange is the process of oxygen entering cells and carbon dioxide leaving cells. It is essential for respiration, which produces ATP for energy.

Question 2

Q: How does gas exchange occur in humans?

Answer 2

A: In humans, gas exchange occurs in the alveoli of the lungs:

Oxygen: Diffuses from alveoli into capillaries and binds with hemoglobin in red blood cells.

Carbon Dioxide: Diffuses from blood into alveoli to be exhaled.

Question 3

How are alveoli adapted for efficient gas exchange?

Answer 3

Large surface area

Thin walls (one cell thick)

Good blood supply

Moist surface for gases to dissolve

Question 4

How does smoking affect the lungs and gas exchange?

Answer 4

Smoking damages alveoli, reducing surface area and elasticity, leading to diseases like emphysema and bronchitis. It also increases the risk of lung cancer.

Question 5

What are the practical experiments to investigate gas exchange?
Investigating the Release of Carbon Dioxide in Exhaled Air:

Answer 5

Method: Breathe out through a straw into limewater.

Positive Result: Limewater turns cloudy, indicating CO₂ is present.

Negative Result: Limewater remains clear if no CO₂ is present.

Question 6

What are the practical experiments to investigate gas exchange?
Investigating the Effect of Exercise on Breathing Rate:

Answer 6

Investigating the Effect of Exercise on Breathing Rate:

Method: Measure the number of breaths per minute before and after exercise.

Positive Result: Breathing rate increases due to higher oxygen demand.

Negative Result: No change in breathing rate if the person is at rest.