Oxygen Transport Flashcards

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1
Q

What is myoglobin

A

Oxygen transport molecule for muscles

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2
Q

What Ion is at the centre of a Haemoglobin ring

A

Iron

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3
Q

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

A

4

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4
Q

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

A

1

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5
Q

What is proximal bound to the iron in haem

A

Histidine residue

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6
Q

What happens when oxygen binds to the Fe in haemoglobin

A

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

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7
Q

How many polypeptides is myoglobin made up of

A

1

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8
Q

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

A

Myoglobin

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9
Q

What type of saturation curve does myoglobin produce

A

Hyperbolic

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10
Q

What type of saturation curve does haemoglobin produce

A

Sigmoidal

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11
Q

How many polypeptide chains is haemoglobin made up of

A

4 (2 alpha, 2 beta)

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12
Q

What are the 2 states of haemoglobin

A

R and T states

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13
Q

What is the T state of haemoglobin

A

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

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14
Q

What is the R state of haemoglobin

A

Haem groups are more exposed so oxygen can bind easier.

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15
Q

What sate does deoxyhaemoglobin exist in

A

T state

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16
Q

Which state of haemoglobin has the lower affinity for oxygen

A

T state

17
Q

What affect does oxygen binding have on the state of haemoglobin

A

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

18
Q

Why is the haemoglobin binding curve sigmoidal

A

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

19
Q

What does it mean by cooperative binding

A

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

20
Q

What molecule regulates oxygen binding

A

2,3-Bisphosphoglycerate

21
Q

How does 2,3-BPG regulate oxygen binding

A

Decreases haemoglobin affinity for oxygen

22
Q

What is the advantages in 2,3-BPG

A

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

23
Q

What is the Bohr effect

A

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

24
Q

What does carbon monoxide do to haemoglobin

A

Binds very tightly preventing oxygen binding

25
Q

What polypeptide chains are present in fetal haemoglobin

A

2 alpha and 2 gamma

26
Q

What is the difference between fetal and maternal haemoglobin

A

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

27
Q

What is a thalassaemia

A

An imbalance between the number of alpha and beta chains

28
Q

What is a beta thalassaemia

A

Decreased or absent beta chains

29
Q

What results from beta thalassaemia

A

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