L24 Respiration - Transportation of gases

Question 1

What is Dalton’s law?

Answer 1

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

Question 3

The concentration of a gas dissolved in a solution is determined using Henry’s law. What is that? (What is ‘dis’)

Answer 3

[Gas]dis = s x Pgas

S - solubility coefficient (mM/mmHg)
P - partial pressure of the gas

Question 4

What would happen to the concentration of oxygen if you increase the partial pressure of oxygen?

Answer 4

If PO2 increases then [O2] increases

Question 5

What is the molecular weight of haemoglobin?

Answer 5

68kD

Question 6

What does each unit in the haemoglobin consist of? (Clean)

Answer 6

Haemoglobin has a tetrameric structure with four subunits,

Each unit consist of a Haem unit and a globin chain
In adult Hg there are:
2alpha chains and 2beta chains

Question 7

What is the structure of haemoglobin?

Answer 7

Haemoglobin has a tertameric structure with four subunits.

Question 8

How many chians are there in an adult haemoglobin?

Answer 8

2α chains and 2β chains

Question 9

The haem unit contains a specific atom. What is this atom and its variants?

Answer 9

Haem unit is a porphyrin containing a single iron atom. Iron has two states: Fe2+ and Fe3+

Question 10

What happens if Fe if in Fe3+ state in haemoglobin ?

Answer 10

The enzyme methaemoglobin reductase helps convert any Fe3+ back to Fe2+ so that the oxygen can bind to the iron as it’s in the Fe2+ state

Question 11

What are the two states that haemoglobin exists in? And what does this mean for affinity for O2?

Answer 11

Haemoglobin exists in two states, tense and relaxed.

In tense state, low affinity for O2
In relaxed state, high affinity for O2

Question 12

Why does haemoglobin have a lower affinity for oxygen when in a tensed state?

Answer 12

Haemoglobin in the tense state has a more compact structure, making it less flexible and less able to bind to oxygen

Question 13

What happens to the oxygen- haemoglobin dissociation curve when temperature increases?

Answer 13

The dissociation curve shifts to the right which means that haemoglobin has a decreased affinity for oxygen, and it releases oxygen more readily at a given partial pressure of oxygen

Question 14

What happens to the oxygen- haemoglobin dissociation curve when you make the pH more acidic (lower)?

Answer 14

It shifts to the right. This means that the haemoglobin has a lower affinity for oxygen, and it releases more readily at a given partial pressure of oxygen

CO2 is acidic

Question 15

What is 2,3 Diphpsphoglycerate?

Question 16

What happens to the oxygen- haemoglobin dissociation curve when you increase 2,3 DPG?

Answer 16

An increase in 2,3 DPG shifts oxygen curve to the right. This means that haemoglobin has a decreased affinity for oxygen. This means that it releases oxygen more readily

Question 17

What happens in tissues when respiration is actively being used?

Answer 17

Increased temperature
Increased CO2 production
Decrease in pH

Shifts dissociation curve to the right
Decreased affinity for O2 on haemoglobin - more O2 released to the tissue

Question 18

Why is the Fetal-Hb different to adult-Hb?

Answer 18

The beta globin chains are replaced by the gamma- chains.

Question 19

Why is it essential for fetals to have their beta globin chains replaced by gamma chains?

Answer 19

There is a leftward shift in the Hb-O2 curve - higher affinity for O2 so they can extract oxygen more efficiently for growth and development

Question 20

Why is the ratio between bicarbonate and CO2 important?

Answer 20

The ratio between the two is crucial for maintaining blood pH. The ratio acts a
S a buffer system, helping to neutralise excess acid or base

Think about balance equation:
CO2 + H2O ↔️ H2CO3 ↔️ HCO3- + H+

Question 21

Last slide use book