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Flashcards in Oxygen Transport Deck (29)
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1

What is myoglobin

Oxygen transport molecule for muscles

2

What Ion is at the centre of a Haemoglobin ring

Iron

3

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

4

4

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

1

5

What is proximal bound to the iron in haem

Histidine residue

6

What happens when oxygen binds to the Fe in haemoglobin

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

7

How many polypeptides is myoglobin made up of

1

8

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

Myoglobin

9

What type of saturation curve does myoglobin produce

Hyperbolic

10

What type of saturation curve does haemoglobin produce

Sigmoidal

11

How many polypeptide chains is haemoglobin made up of

4 (2 alpha, 2 beta)

12

What are the 2 states of haemoglobin

R and T states

13

What is the T state of haemoglobin

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

14

What is the R state of haemoglobin

Haem groups are more exposed so oxygen can bind easier.

15

What sate does deoxyhaemoglobin exist in

T state

16

Which state of haemoglobin has the lower affinity for oxygen

T state

17

What affect does oxygen binding have on the state of haemoglobin

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

18

Why is the haemoglobin binding curve sigmoidal

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

19

What does it mean by cooperative binding

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

20

What molecule regulates oxygen binding

2,3-Bisphosphoglycerate

21

How does 2,3-BPG regulate oxygen binding

Decreases haemoglobin affinity for oxygen

22

What is the advantages in 2,3-BPG

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

23

What is the Bohr effect

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

24

What does carbon monoxide do to haemoglobin

Binds very tightly preventing oxygen binding

25

What polypeptide chains are present in fetal haemoglobin

2 alpha and 2 gamma

26

What is the difference between fetal and maternal haemoglobin

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

27

What is a thalassaemia

An imbalance between the number of alpha and beta chains

28

What is a beta thalassaemia

Decreased or absent beta chains

29

What results from beta thalassaemia

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