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Biology 3 - Organisms Exchange Substances With Their Environment > Haemoglobin > Flashcards

Haemoglobin Flashcards

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1
Q

What is haemoglobin

A

Protein

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2
Q

What is it’s structure

A

Quaternary

4 polypeptides linked together to form 1 molecule

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3
Q

What does each chain have that binds to oxygen to carry it

A

A haem group containing a ferrous iron (Fe2+ ion)

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4
Q

How does haemoglobin tertiary structure allow it to bind to oxygen

A

Gives it its specific shape

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5
Q

What problem are pigments like haemoglobin used to overcome

A

The low solubility of oxygen in water e.g dissolving in blood

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6
Q

How many binding sites does haemoglobin have to carry oxygen

A

4

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7
Q

What is the binding of oxygen called

Where does this take place

A

Loading/associating

In the lungs

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8
Q

What’s the process where haemoglobin releases oxygen called

Where does this take place

A

Unloading/dissociating

Tissues

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9
Q

What affinity would haemoglobin have if it could take up oxygen easily but release it less easily

A

High

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10
Q

Describe haemoglobin with low affinity

A

Take up oxygen less easily

Release oxygen easily

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11
Q

Describe how the 4 polypeptide chains cooperate to bind with oxygen

A
  1. Oxygen binds to haem group of 1st polypeptide
  2. Triggers a change in shape of other 3
  3. Change in shape increases their oxygen affinity
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12
Q

What’s % saturation

A

% of haemoglobin that has oxygen bound to its haem group

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13
Q

What tissues have least % saturation

A

Heavily respiring - 3 oxygen may be released from each haemoglobin

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14
Q

What are gas concentrations expressed as

A

Partial pressures (kPa)

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15
Q

What is the product called in the lungs when oxygen and haemoglobin bind

A

Oxyhaemoglobin

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16
Q

What surroundings is haemoglobin more likely to dissociate in
Why

E.g

A

Low oxygen levels
Due to increased CO2 levels

E.g repairing tissues (muscles)

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17
Q

What’s the graph that shows the loading and unloading

A

The dissociation curve

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18
Q

What areas does haemoglobin associate with oxygen

E.g

A

High levels of oxygen areas

E.g gas exchange surfaces, lungs

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19
Q

What areas does haemoglobin dissociate from oxygen

E.g

A

Low oxygen areas

E.g respiring tissue

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20
Q

What do oxygen dissociation curves show at the start

A

There is initially a slow uptake of haemoglobin

21
Q

Why is there initially a slow uptake by haemoglobin at start

A

As the shape makes it difficult for oxygen to bind at first

4 polypeptide chains are close together

22
Q

After the 1st oxygen molecule has bound what allows the oxygen molecules to bind easier

A

The conformational change (positive cooperativity)

23
Q

What is the graph like when there is positive cooperativity

A

Steep

24
Q

What happens to rate of saturation when 3rd oxygen molecule binds
Why

A

Slows down

As there’s only 1 binding site left on the haemoglobin so probability of binding is lower

25
Q

What happens to the graph when the 3rd molecule of oxygen has bound

A

Slows and flattens off

26
Q

Which way does the graph shift is its high affinity

A

Left and higher

27
Q

Which way does the graph shift is its low affinity

A

Right , lower

28
Q

3 factors that can effect unloading of oxygen

A

Temperature
CO2
pH level

29
Q

What is a change to the dissociation curve due to CO2/pH called

A

The Bohr Shift

30
Q

When gas exchange surfaces have low CO2 levels what happens to the affinity for O2 e.g in lungs
What does the graph do

A

Increases

Higher left

31
Q

What happens to affinity if CO2 levels are higher

What does the graph do

A

Decreases

Lower, right

32
Q

What does CO2 form when it diffuses into plasma from rbc’s and dissolves (pH)

A

Carbonic Acid

33
Q

What releases when CO2 forms carbonic acid

A

Releases H+ ions that will bind to haemoglobin and cause oxygen to be released

34
Q

What do H+ ions do to blood ph

A

Decrease it

35
Q

What does a lower blood pH cause (loading/unloading)

A

Increase in unloading of oxygen

36
Q

What does ph do when respiring

A

Drops (more acidic)

37
Q

What’s the Bohr affect caused by

A

Increase in CO2

38
Q

What happens in the Bohr affect

A

Increase in CO2 so more demand for oxygen
Muscles need more oxygen for aerobic respiration
Unload oxygen easier from haemoglobin to meet demand

39
Q

What does oxygen balance out

A

Carbonic Acid

40
Q

How does a lot of respiration cause oxygen to become available

A 
More CO2 in tissues
Lower ph
Greater haemoglobin change
Oxygen more readily dissociated
So more available for respiration
41
Q

What catalyses CO2 + H2O in RBCs

A

Carbonic anhydrase

42
Q

Where do the HCO3- ions go when carbonic Acid is broken down

What does this do to red blood cells

A

Into plasma

Gives them a positive charge

43
Q

What is red blood cells positive charge counteracted by

What’s this called

A

Cl- entering RBC

called the chlorine shift

44
Q

What’s the affinity of foetal haemoglobin like

Why

A

High

As pp of oxygen is much lower in womb than lungs

45
Q

What are animals that live in high altitudes (llama) adapted to
Where is curve

A

Adapted to bind more oxygen at lower partial pressures

Curve is at high affinity - High, left

46
Q

What size mammals have a lower oxygen affinity

Why

A

Smaller mammals e.g mouse
Have larger SA:volume ratio so they lose heat fast. Have higher respiratory rate to keep themselves warm when needed so allow oxygen to be unloaded easily at respiring tissues

47
Q

What is myoglobin

What is its job

A

Found in muscle tissue

Jon is to bind any oxygen that is released by haemoglobin in the blood

48
Q

2 factors that cause variation in haemoglobin

A

Variations in primary structure - different amino acid sequences

Adaptations to environmental conditions e.g different partial pressures of oxygen

49
Q

What is the condition that causes red blood cells to change shape due to variations in haemoglobin increasing risk of blood clots

A

Sickle cell anaemia

Biology 3 - Organisms Exchange Substances With Their Environment (6 decks)

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