Biology: Haemoglobin and Oxygen Curves

Question 1

What type of protein is haemoglobin?

Answer 1

globular protein, quaternary structure

Question 2

What is the main role of red blood cells?

Answer 2

transport oxygen to respiring cells during aerobic respiration

Question 3

Outline the primary structure of haemoglobin

Answer 3

sequence of amino acids within four polypeptide chains

Question 4

Outline the secondary structure of haemoglobin

Answer 4

polypeptide chains coiled into helix

Question 5

Outline the tertiary structure of haemoglobin

Answer 5

each chain folded into precise shape essential for oxygen association

Question 6

Outline the quaternary structure of haemoglobin

Answer 6

chain joined via disulphide bridges to form spherical molecule. each chain associated with prosthetic haem group

Question 7

What can each Fe2+ ion do?

Answer 7

combine with singular oxygen molecule (O2)

Question 8

How many O2 molecules can haemoglobin associate with?

Answer 8

4 molecules

Question 9

How many atoms of oxygen are associated with haemoglobin?

Answer 9

8 oxygen atoms

Question 10

What is meant by oxygen loading?

Answer 10

oxygen associates with haemoglobin by binding to each haem group

Question 11

What is meant by oxygen unloading?

Answer 11

oxygen dissociates from haemoglobin at respiring tissue

Question 12

What is formed when oxygen binds to haemoglobin?

Answer 12

oxyhaemoglobin

Question 13

Write the equation for the formation of oxyhaemoglobin

Answer 13

Hb + 4O2 <—> HbO8

Question 14

What is defined by haemoglobins affinity?

Answer 14

ability to attract oxygen

Question 15

What is haemoglobins affinity dependent on?

Answer 15

-partial pressure of oxygen -haemoglobin saturation -partial pressure of carbon dioxide

Question 16

Where will haemoglobin have a high affinity for oxygen?

Answer 16

oxygen rich areas, high ppO2, promotes oxygen association

Question 17

Where will haemoglobin have a low affinity for oxygen?

Answer 17

oxygen starved areas, low ppO2, promotes oxygen dissociation

Question 18

Define the term partial pressure

Answer 18

measure of concentration of a particular gas in a mixture of gases

Question 19

What is meant by haemoglobins saturation?

Answer 19

haemoglobin associated with maximum number of possible O2 molecules

Question 20

How are red blood cells/haemoglobin adapted to its function?

Answer 20

-biconcave shape -thin -flexible

Question 21

How is a biconcave shape an important adaptation?

Answer 21

provides large surface area to volume ratio for greater diffusion

Question 22

How is being thin an important adaptation?

Answer 22

short diffusion distance

Question 23

How is being flexible an important adaptation?

Answer 23

squeeze through capillaries for short diffusion distance

Question 24

What factor causes difficulty for the first oxygen molecule to associate?

Answer 24

-shape of haemoglobin -binding sites closely united

Question 25

Referring to an oxygen dissociation graph, what happens at low concentrations of oxygen?

Answer 25

-little oxygen binds -gradient of curve initially shallow

Question 26

When the first oxygen molecule binds, what happens?

Answer 26

-quaternary structure changes shape -induces other subunits to bind

Question 27

What happens to allow for the second oxygen molecule to bind?

Answer 27

-small increase in ppO2 -positive cooperativity -gradient of curve steepens

Question 28

What happens after the third oxygen has bound?

Answer 28

-hard for fourth to bind -less active sites available -gradient lowers, graph flattens off

Question 29

If the graph is further to the left, what does this mean for oxygens affinity?

Answer 29

-affinity greater -associates readily -dissociates poorly

Question 30

If the graph is further to the right, what does this mean for affinity?

Answer 30

-affinity lower -associates less readily -dissociates efficiently