Respiration 3 transport of gases

Question 1

What is Dalton’s law?

Answer 1

The total pressure of a mixture of gases is the sum of their individual partial pressures

Question 2

How do you calculate the amount of gas dissolved in solution?

Answer 2

Partial pressures

Question 3

How is the concentration of gas dissolved in solution calculated?

Answer 3

-[Gas]dis = s x Pgas
-S = solubility coefficient (mM/mmHg)
-P = partial pressure of gas

Question 4

What is the solubility of O2 like in saline?

Answer 4

Relatively low solubility

Question 5

Describe the structure of haemoglobin

Answer 5

-has a tetrameric structure - 4 subunits
-each consists of a haem unit + globular chain - different combinations of globular chain depending on Hb type

Question 6

What are the chains in adult and foetal haemoglobin?

Answer 6

-adult = 2 alpha chains + 2 beta chains
-foetal = 2 alpha chains + 2 gamma chains

Question 7

What is a haem unit?

Answer 7

A porphyrin ring contains a single iron atom

Question 8

For oxygen to bind in haemoglobin, what state does iron have to be in?

Answer 8

-Fe2+ state
-enzyme methaemoglobin reductase converts Fe3+ to Fe2+

Question 9

What are the 2 states of haemoglobin?

Answer 9

-tense state - low affinity for O2
-relaxed state - high affinity for O2

Question 10

Which of the 4 O2 molecules that can bind is the hardest to bind?

Answer 10

The first one

Question 11

What is the effect of increasing temperature on a haemoglobin curve?

Answer 11

Increased temp = curve shift to the right

Question 12

What is the effect of pH (CO2) on a haemoglobin curve?

Answer 12

Decreased pH (increased CO2) = curve shift right

Question 13

What is the effect of 2,3 diphosphoglycerate on a haemoglobin curve?

Answer 13

Increase = curve shifts to the right

Question 14

What does the blood carry CO2 as?

Answer 14

-dissolved CO2
-carbonic acid
-bicarbonate
-carbonate
-carbamino compounds

Question 15

How it CO2 transported from cells?

Answer 15

-moves out of cell across membrane + enters plasma
-CO2 can remain in plasma, but most enters r.b.c
-CO2 in plasma: some dissolved, some combined to plasma proteins, some converted to bicarbonate

Question 16

How can CO2 enter red blood cells?

Answer 16

-by passing through aquaporin 1
-reese’s associated transport protein
-small amount diffuses through lipid bilayer

Question 17

What happens to the CO2 that is in the red blood cell?

Answer 17

-some dissolves
-some binds to haemoglobin
-the rest is converted to carbonate in presence of carbonic anhydrase

Question 18

How is bicarbonate transported out of red blood cell?

Answer 18

By chloride-bicarbonate exchanger