Oxygen Transport

Question 1

What is myoglobin

Answer 1

Oxygen transport molecule for muscles

Question 2

What Ion is at the centre of a Haemoglobin ring

Answer 2

Iron

Question 3

How many nitrogen atoms are bound to the centre iron in the haem ring

Answer 3

4

Question 4

How many oxygen molecules can bind to the iron in the centre of a haem group

Answer 4

1

Question 5

What is proximal bound to the iron in haem

Answer 5

Histidine residue

Question 6

What happens when oxygen binds to the Fe in haemoglobin

Answer 6

The age moves up into the plane of the ring, moving histidine up with it

Question 7

How many polypeptides is myoglobin made up of

Answer 7

1

Question 8

Which molecule has a high affinity for oxygen; haemoglobin or myoglobin

Answer 8

Myoglobin

Question 9

What type of saturation curve does myoglobin produce

Answer 9

Hyperbolic

Question 10

What type of saturation curve does haemoglobin produce

Answer 10

Sigmoidal

Question 11

How many polypeptide chains is haemoglobin made up of

Answer 11

4 (2 alpha, 2 beta)

Question 12

What are the 2 states of haemoglobin

Answer 12

R and T states

Question 13

What is the T state of haemoglobin

Answer 13

Haem groups are not exposed, making it difficult for oxygen to bind. This is due to interactions between histidine and aspartate which stabilises the structure

Question 14

What is the R state of haemoglobin

Answer 14

Haem groups are more exposed so oxygen can bind easier.

Question 15

What sate does deoxyhaemoglobin exist in

Answer 15

T state

Question 16

Which state of haemoglobin has the lower affinity for oxygen

Answer 16

T state

Question 17

What affect does oxygen binding have on the state of haemoglobin

Answer 17

Gives a conformational change as histidine and Fe move up. This makes it easier for the next oxygen molecule to bind.

Question 18

Why is the haemoglobin binding curve sigmoidal

Answer 18

As the haemoglobin transitions from the T to R state, its easier for oxygen to bind and so the curve becomes steeper

Question 19

What does it mean by cooperative binding

Answer 19

The binding of one molecule of oxygen makes it easier for other oxygen molecules to bind

Question 20

What molecule regulates oxygen binding

Answer 20

2,3-Bisphosphoglycerate

Question 21

How does 2,3-BPG regulate oxygen binding

Answer 21

Decreases haemoglobin affinity for oxygen

Question 22

What is the advantages in 2,3-BPG

Answer 22

It allows oxygen to be released in low partial pressure like the respiring tissues

Question 23

What is the Bohr effect

Answer 23

When Hydrogen ions and carbon dioxide bind to haemoglobin lowering its affinity for oxygen

Question 24

What does carbon monoxide do to haemoglobin

Answer 24

Binds very tightly preventing oxygen binding

Question 25

What polypeptide chains are present in fetal haemoglobin

Answer 25

2 alpha and 2 gamma

Question 26

What is the difference between fetal and maternal haemoglobin

Answer 26

Fetal has a higher affinity for oxygen allowing transfer from maternal to fetal

Question 27

What is a thalassaemia

Answer 27

An imbalance between the number of alpha and beta chains

Question 28

What is a beta thalassaemia

Answer 28

Decreased or absent beta chains

Question 29

What results from beta thalassaemia

Answer 29

Alpha chain precipitate, fetal haemoglobin or haemoglobin made up of 4 gamma chains