Respiration: Gas Transport/Carriage

Question 1

Which gas is more diffusable? O2 or CO2

Answer 1

CO2

Question 2

How does movement of gas throughout resp system occur?

Answer 2

via diffusion

Question 3

What properties help for facilitation of gas diffusion?

Answer 3

1) Large surface area
2) Large partial pressure gradients
3) Specialised transport mechanisms for transporting O2 and CO2 between lungs & tissues (haemoglobin)

Question 4

How is oxygen transported through the body?

Answer 4

• Dissolved in blood (not enough so Hb has to help)

- Bound to haemoglobin (Hb)

Question 5

What is the makeup of a haemoglobin (Hb) molecule?

Answer 5

4 heme groups joined onto a globin protein (2 alpha and 2 beta polypeptide chains)

Question 6

How does oxygen bind to Hb?

Answer 6

Each heme group contains iron which oxygen binds to (total of 4 per molecule).

MAX 4 oxygen per haemoglobin molecule

Question 7

Is O2 binding to Hb reversible or irreversible?

Answer 7

Reversible

Question 8

What is the respiratory exchange ratio?

Answer 8

Rate of EXPIRED CO2 to O2 UPTAKE (norm is approx 0.8:1)

Question 9

How is CO2 transported?

Answer 9

Carried in blood in 3 forms:

1) DIssolved in blood
2) Bound to Hb
3) As bicarbonate HCO3-

Question 10

Why are CO2 and bicarbonate HCO3- important in the body?

Answer 10

They regulate H+ ions as well as the acid-base balance of the body