Haemoglobin

Question 1

What type of protein is haemoglobin

Answer 1

Globular

Question 2

Why is it good that red blood cells do not contain a nucleus

Answer 2

Provides more space inside the cell for haemoglobin so that they can transport as much O2 as possible

Question 3

What structure does haemoglobin have

Answer 3

Quaternary made up of 4 polypeptide chains

Question 4

Describe the globin proteins in a haemoglobin

Answer 4

Four globin subunits are held together by disulphide bonds
Arranges so their hyrophobic R groups are facing inwards helping to preserve the three dimensional spheric shape
The hydrophilic R groups face outwards to maintain solubility

Question 5

What does the haem group contain

Answer 5

Fe2+ which is able to reversibly combine with an oxygen molecules to form oxyhaemoglobin

Question 6

How many oxygen molecules can be carried in a haemoglobin

Answer 6

Because of their four haem mgroups they can carry four oxygen molecules or 8 oxygen atoms

Question 7

What is haemoglobins function

Answer 7

Binding oxygen in lungs and transporting the oxygen to the tissue to be used in aerobic metabolic pathways

Question 8

Why can oxygen be carried efficiently

Answer 8

Oxygen isn’t very soluble in water and haemoglobin is

Question 9

What does the Fe2+ allow when transporting haemoglobin

Answer 9

Allows O2 to be reversibly bind
No amino acids that make up the polypeptide chains in haemoglobin are well suited to binding with oxygen

Question 10

What does the oxygen bind to

Answer 10

The haem groups

Question 11

Whats another word for red blood cells

Answer 11

Erythrocytes

Question 12

Equation for haemoglobins binding to oxygen

Answer 12

Oxygen + Haemoglobin <-> Oxyhaemoglobin

4O2 + Hb <-> Hb4O2

Question 13

Process name of O2 binding

Answer 13

Cooperative bindig

Question 14

Describe cooperative binding

Answer 14

Binding of first O2 molecule results in conformational change in the structure of the haemoglobin molecule
so its easier for each successive O2 to bind

Question 15

How are red blood cells adapted for O2 transport

Answer 15

Red blood cells lack nuclei = more space for haemoglobin
Biconcave shape = high SA:V, so there is a short diffusion distance for O2

Question 16

What does the oxygen dissociation curve show

Answer 16

Rate at which oxygen associated and dissociates with haemoglobin at different partial pressures of oxygen

Question 17

Whats the partial pressure of oxygen meanign

Answer 17

Partial pressure of O2 refers to the pressure exerted by oxygen within a mixture of gases, a measure of oxygen concentration

Question 18

What occues to O2 when haemoglobin has a higher affinity for oxygen

Answer 18

Haemoglobin can bind easily and dissociate slowly

Question 19

Which way does the curve move for high and low CO2 affinity

Answer 19

High affinity = right
Low affinity = left

Question 20

When is oxygen associated and where

Answer 20

Gas exchange surface
When O2 conc is high, CO2 conc is low and affinity of haemoglobin for O2 is high

Question 21

When is oxygen dissociated and where

Answer 21

Repiring tissues
When O2 conc is low, CO2 conc high, and affinity of haemoglobin for O2 is low

Question 22

Where does loading/ associating take place

Answer 22

In lungs

Question 23

Where does unloading and dissociating take palce

Answer 23

Tissues

Question 24

WHen do haemoglobins take up more O2 easily

Answer 24

Haemoglobin with high affinity for O2 = load easily and release less easily

Question 25

Describe the quanternary structure of haemoglobin

Answer 25

Four polypeptides are linked to form a spherical molecule
Each polyppetide is associated with a haem group which contains Fe2+ and can combine with a single O2

Question 26

How can substance X benefit endurance for athletes

Answer 26

Results in more red blood cells which means athletes have more haemoglobin
So more oxygen can be offloaded and absorbed
More ATP is released and used for muscle contraction
Delays anaerobic respiration

Question 27

What structure protein is haemoglobin

Answer 27

Quaternary with four polypeptide chains two alpha globins and two beta globins, each with a prosthetic haem group

Question 28

How are the four globin subunits held together

Answer 28

Disulphide bonds arranges with hydrophobic R group inwards and hydrophilic outwards

Question 29

What does the prosthetic haem contain

Answer 29

Iron II ion (Fe2+)

Question 30

Haemoglobins functions

Answer 30

-Oxygen binding and transporting
-Oxygen is insoluble in water but haemoglobin is soluble so can be caried efficiently
-Haem enables small molecueles to be bound more easily because each oxygen binds alters quaternary structure so other oxygen has higher chance of binding
-Iron II ion allows O2 to reversible bind

Question 31

What two types of globin proteins make up the haem group

Answer 31

Two alpha globins and two beta globins

Question 32

What is haemoglobins functions

Answer 32

1) binding O2 in lungs and transporting it to tissue for aerobic metabolic pathways
2) O2 not soluble inwater and haemoglobin is, O2 canbe carried more efficiently around the body
3) Existence of Fe2+ alows O2 to be reversible bind as amino acids arent well suited

Question 33

WHat happens if haemoglobin decreases in the bloodq

Answer 33

Fewer haemoglobin so less O2 is delivered o muscles
Less O2 means reduces AEROBIC RESPIRATION
Which means less ATP available for muscle contraction, reducing muscle contraction

Question 34

Advantage of someone having less haemoglobin if haemoglobin has a lower affnity for O2

Answer 34

(Graph shifts right) so haemoglobin has a lower affinity
Haemoglobin dissociates MORE oxygen
So oxygen is available for use in aerobic respiration
Demand for ATP can be met at lower haemoglobin concentrations

Question 35

Roles of haemoglobin

Answer 35

1) transport oxygen to aerobic metabolic pathways
2) Removing CO2 from respiring tissues
3) Dissociating oxygen from haemoglobin at respiring tissues

Question 36

Advantage of having a low affinity for O2

Answer 36

Dissociates at tissues more easily
So can have a greater rate of respiration