2.3 Respiration
***Aerobic respiration equation:
glucose + oxygen → carbon dioxide + water + lots of energy (as
ATP)
C6H12O6 + 6O2 → 6CO2 + 6H2O + C10H16N5O13P3 (lots)
***Anaerobic respiration equation (animals):
glucose → lactic acid + little energy (as ATP)
C6H12O6 → 2C3H6O3 + C10H16N5O13P3 (little)
***Anaerobic respiration equation (plants and fungi):
glucose → ethanol + carbon dioxide + little energy (as
ATP)
C6H12O6 → 2C2H5OH + 2CO2 + C10H16N5O13P3 (little)
● Aerobic respiration normally occurs (glucose is completely broken down), while
anaerobic respiration occurs when there is shortage/absence of oxygen
● ***E.g.: when an athlete is exercising very hard, oxygen supply may be insufficient
to support aerobic respiration, in this case some energy for exercise may be
obtained from glucose by anaerobic respiration, lactic acid formed as consequence
as “oxygen debt”, athlete breathes harder after exercise, allowing lactic acid to be
reprocessed to glucose
● Plants: root hair cells usually respire aerobically, however if soil is flooded, air
spaces filled with water, root hair cells turns to respire anaerobically, if flooding too
long, ethanol produced kills plant
● Fungi: yeast uses up all oxygen when making bread during aerobic respiration, then
switches to anaerobic respiration and produces ethanol and carbon dioxide, carbon
dioxide makes bread rise, ethanol evaporates during baking
ATP (Adenosine triphosphate)
● In respiration, glucose reacts with oxygen, forming ATP which is used by cells
● ATP provides energy for cells, allows cells to store energy briefly and transport it
(referring to ATP) within the cell to support endergonic (能量的) chemical
reactions
1
***Aerobic respiration equation:
glucose + oxygen → carbon dioxide + water + lots of energy (as
ATP)
C6H12O6 + 6O2 → 6CO2 + 6H2O + C10H16N5O13P3 (lots)
***Anaerobic respiration equation (animals):
glucose → lactic acid + little energy (as ATP)
C6H12O6 → 2C3H6O3 + C10H16N5O13P3 (little)
***Anaerobic respiration equation (plants and fungi):
glucose → ethanol + carbon dioxide + little energy (as
ATP)
C6H12O6 → 2C2H5OH + 2CO2 + C10H16N5O13P3 (little)
● Aerobic respiration normally occurs (glucose is completely broken down), while
anaerobic respiration occurs when there is shortage/absence of oxygen
● ***E.g.: when an athlete is exercising very hard, oxygen supply may be insufficient
to support aerobic respiration, in this case some energy for exercise may be
obtained from glucose by anaerobic respiration, lactic acid formed as consequence
as “oxygen debt”, athlete breathes harder after exercise, allowing lactic acid to be
reprocessed to glucose
● Plants: root hair cells usually respire aerobically, however if soil is flooded, air
spaces filled with water, root hair cells turns to respire anaerobically, if flooding too
long, ethanol produced kills plant
● Fungi: yeast uses up all oxygen when making bread during aerobic respiration, then
switches to anaerobic respiration and produces ethanol and carbon dioxide, carbon
dioxide makes bread rise, ethanol evaporates during baking
ATP (Adenosine triphosphate)
● In respiration, glucose reacts with oxygen, forming ATP which is used by cells
● ATP provides energy for cells, allows cells to store energy briefly and transport it
(referring to ATP) within the cell to support endergonic (能量的) chemical
reactions
1
