Mass Transport (haemoglobin) Flashcards

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1
Q

Define mass transport

A

Bulk movement of liquid or gas in one direction

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2
Q

What determines the need for a mass tansport system and a pump?

A

Sa:vol
Rate of metabolism

Small sa:vol = not enough substances can be exchanged quick enough to supply volume do to long diffusion pathway

High rate of metabolism= many substances bed to be exchanged in a short amount of time= diffusion doesn’t take place quick enough

Need pump and mass transport system

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3
Q

Name features of mass transport system

A
Closed system
Mechanisms to control rate of flow
Mechanisms to ensure unidirectional flow
Mechanisms for mass flow
Suitable medium (gas or liquid)
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4
Q

Explain the importance of a suitable medium to a mass transport system

A

Must be able to Dissolve substances (e.g water)

To transport them easily

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5
Q

Explain the importance of having a mechanism for mass flow to a mass transport system

A

More rapid than diffusion

Maintain conc gradient

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6
Q

Explain the importance of a closed to a mass transport system

A

Allows all cells to be reached

Allows pressure variation for flow of substances

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7
Q

Explain the importance of unidirectional flow to a mass transport system

A

Prevent back flow

Maintain conc gradient

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8
Q

Explain the importance of controlling the rate of flow in a mass transport system

A

Adapt to the changing needs of tissues

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9
Q

Why are humans said to have a double circulatory system?

A

Blood flows in two loops to and from the heart

Pulmonary circulation (to lungs and back)

Systemic circulation (to body and back)

Two sides of the heart

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10
Q

Why is a double circulatory system required in humans?

A

Allows high pressure to be maintained

Pa reduced in lungs as goes through pulmonary capillaries

Low pa= slow flow= wouldn’t reach tissue fast enough, not returned to heart fast enough

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11
Q

Name arteries and veins supplying kidneys

A

Renal arteries/veins

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12
Q

How are redblood cells adapted for oxygen transport?

A

Biconcave disc= flexible (scrap along cappilary walls to provide short diffusion pathway) + short diffusion pathway (thin middle) + larger sa:vol

No organelles= more space for haemoglobin + flexible

Small= compressed against capillary walls (sdp)

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13
Q

Why is it an advantage for rbc to be flexible?

A

Allows them to scrap along and be compressed against capillary walls= sdp

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14
Q

Describe 1° structure of haemoglobin

A

Specific sequence of Amino acids

Polypeptide chains=

2 X alpha

2 X beta

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15
Q

Describe 2° structure of haemoglobin

A

Polypeptide chains coil into alpha helices

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16
Q

Describe 3° structure of haemoglobin

A

Polypeptide chains fold again into specific 3D shape

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17
Q

Describe 4° structure of haemoglobin

A

4 polypeptide chains associate to form a roughly spherical shape

Each polypeptide associates with one haem group (containing ferrous iron ion Fe2+)

18
Q

How many oxygen atoms can one heam group bond to?

A

2x oxygen ATOMS

1x oxygen MOLECULE

19
Q

How many oxygen molecules and atoms can one haemoglobin molecule carry ?

A

8 atoms

4 molecules

20
Q

What is haemoglobin role and how is it adapted to this?

A

Load oxygen at lungs unload oxygen at respiring tissue

Have high affinity at high ppa but low affinity at high ppa

21
Q

Define affinity

A

Chemical attraction

22
Q

Define loading of oxygen

A

Association of an O2 molecule to a haem group

23
Q

Define unloading of O2

A

Dissociation of O2 molecule

24
Q

What affect haemoglobin shape?

A

CO2 conc

DNA (1° structure)

25
Q

Where is the partial pressure of O2 low?

A

At respiring tissue as its being used for Respiration

26
Q

What is an oxygen dissociation curve

A

Graph showing average saturation of haemoglobin (y) against ppa of O2 (X)

27
Q

What does the oxygen dissociation curve show? How?

A

Bind of 1st oxygen molecule if hardest (shallow gradient)

Binding of second and third is increasingly easier (increasing gradient= small increase in partial pressure causes lots more O2 to bind)

Binding of 4th O2 is harder (shallowing gradient)

28
Q

Define positive cooperativity

A

Binding of first O2 makes binding or 2nd and 3rd easier

29
Q

Describe and explain positive cooperativity

A

Bind of 1st oxygen molecule if hardest because globins are compact

Binding of second and third is increasingly easier because binding of 1st O2 changes haemoglobin shape making binding easier

Binding of 4th O2 is harder due to probability (only 1 haem group left to bind)

30
Q

Define partial pressure

A

Pressure exerted by one gas if it singly occupied to same volume

31
Q

Why Is ppa more useful than concentration

A

Concentration of O2 is constant

Ppa varies due to how many particles of gases are in the air (same composition but differ e renumber of particles= different pressure exerted)

32
Q

Why is oxygen only unloaded at respiring tissue?

A

Ppa of O2 in blood is roughly constant

33
Q

Name the effect of CO2 on haemoglobin

A

Bohr effect

34
Q

Describe and explain the bohr effect

A

Increase rate of Respiration= increase CO2 conc= decrease PH = change in shape to haemoglobin = decreased affinity for O2= O2 is readily unloaded/dissociated =O2 available for Respiration

35
Q

Why does increase in CO2 conc mean a decrease in PH?

A

CO2 dissolves in blood plasma to form carbonic acid

36
Q

Compared the change in oxygen affinity for large and small changes in CO2 conc

A

Small change = small change in affinity

Large change =large change in affinity

37
Q

In which direction does the oxygen dissociation curve move with an increase in CO2 conc? Why?

A

Right

At all ppa’s % sat is always lower (more readily unloads)

38
Q

In which direction does the oxygen dissociation curve move with an decrease in CO2 conc? Why?

A

Left

Always a higher % sat (more readily loads)

39
Q

How do you calculate partial pressure?

A

Concentration X atmospheric pressure

40
Q

How does a large sa:vol affect the oxygen dissociation curve? Why?

A

Move to right

Lose heat fast = large rate of Respiration = large demand for O2 (needs to readily unload)

41
Q

How does the oxygen dissociation curve move for a cold animal? Why?

A

To left

Cold= slower rate of Respiration = less demand for O2 = less demand for O2 (doesn’t need to unload as much)