3.2 Haemoglobin & CO2 transport

Question 1

What type of molecule is haemoglobin?

Answer 1

Conjugated protein with a haem group - 4 polypeptide chains

Question 2

Haemoglobin is found where?

Answer 2

In RBCs

Question 3

Haemoglobin bings to what?

Answer 3

Oxygen

Question 4

What is the role of Haemoglobin?

Answer 4

To transport oxygen around the body

Question 5

To be efficient what must Haemoglobin do?

Answer 5

Readily associate with oxygen at exchange surfaces

Readily dissociate from oxygen when tissues need it

Question 6

What is it called when oxygen and Haemoglobin bind?

Answer 6

Oxyhaemoglobin

Question 7

What are the two types of Haemoglobin?

Answer 7

Haemoglobin with high affinity for oxygen

Haemoglobin with low affinity for oxygen

Question 8

Haemoglobin with high affinity for oxygen does what?

Answer 8

Takes oxygen up easily

Hard to release

Question 9

Haemoglobin with a low affinity for oxygen does what?

Answer 9

Takes it up less easily

Releases it readily

Question 10

What is loading or associating?

Answer 10

The process of oxygen combining with Haemoglobin at exchange surfaces

Question 11

What is unloading or dissociating?

Answer 11

Oxygen released

Question 12

At low concentrations of oxygen what is it difficult to do?

Answer 12

Absorb oxygen

Question 13

Once the first oxygen is loaded what do the remaining 3 molecules do?

Answer 13

Load easily

Question 14

The further to the left the higher the what?

Answer 14

Affinity for oxygen

Question 15

Where is myoglobin found?

Answer 15

In muscle

Question 16

What does myoglobin have/do?

Answer 16

High affinity for oxygen
One haem group
Acts as oxygen reserve

Question 17

When carbon dioxide diffuses into bloodstream what does 10-20% do?

Answer 17

Binds to amine groups forming carbaminohaemoglobin

Question 18

75-85% of carbon dioxide is converted into what?

Answer 18

Hydrogen carbonate by carbonic anhydrase

Question 19

H2CO3 dissociates into what?

Answer 19

H+

HCO3-

Question 20

The HCO3- moves out of RBCs to where?

Answer 20

Plasma

Question 21

Negatively charged chloride ions move into where?

Answer 21

RBCs

Question 22

Why does foetal Haemoglobin have a higher affinity for oxygen?

Answer 22

To maximise oxygen uptake from the mothers bloodstream which has already used some up by the time it reaches the placenta

Question 23

CO2 lowers Haemoglobins what?

Answer 23

Affinity for oxygen

Question 24

Dissolved CO2 has what effect on pH and what does this do? What is this called?

Answer 24

Lowers PH because it is acidic
Causes proteins to change shape releasing CO2
BOHR EFFECT

Question 25

The Bohr effect is important to provide what?

Answer 25

Necessary for providing oxygen to active tissues readily

Oxygen binding easily in lungs

Question 26

At gas exchange surfaces what is removed?

Answer 26

CO2

Question 27

Low levels of CO2 increases what?

Answer 27

PH

Question 28

High pH changes what?

Answer 28

Haemoglobin so oxygen loads readily - increased affinity

Question 29

In tissues where CO2 is made, pH decreases so what happens?

Answer 29

Haemoglobin changes shape
Lowers affinity for O2
So it is unloaded into respiring tissues