5 - Mass Transport Flashcards
Define haemoglobin
Protein in a RBC that transports oxygen
Haemoglobin has …. polypeptide chains
4
What does haemoglobin form with oxygen?
Oxyhaemoglobin
Describe the structure of haemoglobin (5)
Made of 4 subunits Each subunit has a haem group Each haem group has Fe2+ The shape changes when O2 bonds The shape changes when the pH is lowered
Why is haemoglobin made of 4 subunits?
4 O2 molecules can be transported
Why is blood red?
The haem group contains Fe2+
Why does haemoglobin have an affinity for oxygen?
Contains Fe2+ (bond)
Why does the shape of haemoglobin change when O2 is bonded to it?
Other oxygen molecules can load easily
When does the shape of haemoglobin change? (2)
O2 bonded to it
pH is lowered
Why does the shape of haemoglobin change when the pH is lowered?
Oxygen molecules unload in respiring tissue
Process of transporting oxygen by haemoglobin (3)
1 - Readily associate with O2 at surface where gas exchange happens
2 - Readily dissociate from O2 at respiring tissues
3- Does this by forming oxyhaemoglobin
O2 concentration where gas exchange happens
Low
O2 concentration where respiring tissues are
High
CO2 concentration where gas exchange happens
High
CO2 concentration where gas respiring tissues are
Low
Affinity where gas exchange happens
High
Affinity where gas respiring tissues are
Low
Result where gas exchange happens
Oxygen attached
Result where respiring tissues are
Oxygen released
Define affinity
Ability of haemoglobin to bind to oxygen
Equation about haemoglobin
Loading
Hb + 4O2 -> HbO8
Shape of the oxygen dissociated curve
S
Describe the oxygen dissociated curve
1 - Near tissues. Hard to load as low O2 concentration
2 - Changes shape so happens easier
3 - Near lungs - hard to load but high affinity
Does the curve go left or right in foetal haemoglobin?
Left
Does the curve go left or right in the Bohr Shift? Why?
Right - lower CO2 concentration so give sup extra oxygen
Shift where the curve moves right
Bohr Shift
Describe the process of the Chloride Shift
- Carbon dioxide diffuses into the RBCs and combines with water to form carbonic acid
- Carbonic acid dissociates into protons (H+) and bicarbonate ions (HCO3-)
- The protons are buffered on the surface while the bicarbonate ions are actively exchanged across the surface
- Cl- enters the RBC when HCO3- leaves (Hamburger effect)
- This raises the inter-erythrocyte of chlorine
Effect where HCO3- and Cl- are transported
Hamburger effect
Equations for the Chloride Shift
CO2 + H20 ↔ H2CO3 ↔ H+ + HCO3-
H+ + Hb- ↔ HHb
Why do we need a circularity system? (3)
We are big - blood vessels needed
Diffusion is only effective with a short pathway
Need t transport products of digestion to other cells
Define mass transport
Transporting materials around the body
Why do organisms have a transport system? (3)
SA:V decreases as size increases
Exchange surfaces needed for nutrient exchange and removal of products
Exchange surfaces in specific locations