Excretion, CO2 & Nitrogenous Waste.
Excretion is the removal of waste products of metabolism from
the body.
E.g. Removal of urea, water & CO2.
Metabolism is the chemical reactions that occur inside cells.
Metabolic waste is the substances that are toxic or produced in
excess from reactions inside cells.
Egestion is the removal of undigested food that has never been
involved in metabolism.
Deamination is the removal of the amine group from an amino
acid, producing ammonia.
Transporting CO2:
5% of CO2 dissolves into plasma.
10% of CO2:
1. CO2 diffuses into erythrocytes from respiring cells.
2. CO2 combines with haemoglobin to from
carbaminohaemoglobin.
85% of CO2:
1. CO2 diffuses into erythrocytes from respiring cells.
2. CO2 combines with water in the cell to produce H2CO3,
this is catalysed by carbonic anhydrase:
CO2 + H2O H2CO3
3. H2CO3 dissociates in water into protons & hydrogen
carbonate ions:
H2CO3 + H2O H+ + HCO3-
4. Hydrogen carbonate ions diffuse out of the erythrocyte
and into the plasma where it dissolves.
Excretion is the removal of waste products of metabolism from
the body.
E.g. Removal of urea, water & CO2.
Metabolism is the chemical reactions that occur inside cells.
Metabolic waste is the substances that are toxic or produced in
excess from reactions inside cells.
Egestion is the removal of undigested food that has never been
involved in metabolism.
Deamination is the removal of the amine group from an amino
acid, producing ammonia.
Transporting CO2:
5% of CO2 dissolves into plasma.
10% of CO2:
1. CO2 diffuses into erythrocytes from respiring cells.
2. CO2 combines with haemoglobin to from
carbaminohaemoglobin.
85% of CO2:
1. CO2 diffuses into erythrocytes from respiring cells.
2. CO2 combines with water in the cell to produce H2CO3,
this is catalysed by carbonic anhydrase:
CO2 + H2O H2CO3
3. H2CO3 dissociates in water into protons & hydrogen
carbonate ions:
H2CO3 + H2O H+ + HCO3-
4. Hydrogen carbonate ions diffuse out of the erythrocyte
and into the plasma where it dissolves.
