# 78 Aerobic and anaerobic respiration
Respiration releases energy from food.
There are 2 kinds of respiration. Aerobic and anearobic respiration. The main difference between them is that aerobic respiration involves oxygen and anaerobic respiration does not!
A. Aerobic respiration
The release of a relatively large amount of energy in cells by the breakdown of food substances in the presence of O2.
The release of a relatively large amount of energy in cells by the breakdown of food substances in the presence of O2.
B. Anaerobic respiration
Anaerobic respiration: the release of a relatively small amount of energy by the breakdown of food substances in the absence of O2.
Anaerobic respiration in muscles during exercise:
Anaerobic respiration: the release of a relatively small amount of energy by the breakdown of food substances in the absence of O2.
Anaerobic respiration in muscles during exercise:
Anaerobic respiration in yeast:
Muscles respire anaerobically when exercising vigorously, because the blood cannot supply enough oxygen to maintain aerobic respiration. Howerver, the formation and build-up of lactic acid in muscles causes cramp (muscle fatigue).
In the liver, lactic acid is oxidised after the exercise by the extra oxygen provided by fast breathing. An oxygen debt is created because oxygen is needed to convert lactic acid back to a harmless chemical (pyruvic acid).
Bread making
- yeast is mixed with water to activate it then added to flour to make dough
- mixture -----> warm place ------> rise
- yeast releases CO2 ------> dough rises
* a warm to is important because fermentation is controlled by enzymes
- when dough is cooked, high to kills yeast and evaporates any formed ethanol
- air spaces are left where CO2 was trapped
In the liver, lactic acid is oxidised after the exercise by the extra oxygen provided by fast breathing. An oxygen debt is created because oxygen is needed to convert lactic acid back to a harmless chemical (pyruvic acid).
Bread making
- yeast is mixed with water to activate it then added to flour to make dough
- mixture -----> warm place ------> rise
- yeast releases CO2 ------> dough rises
* a warm to is important because fermentation is controlled by enzymes
- when dough is cooked, high to kills yeast and evaporates any formed ethanol
- air spaces are left where CO2 was trapped
Brewing
- yeast is added to a source of sugar (fruit juice or germinated barley grains) and kept in warm conditions
- fermentation (yeast respires the sugar) occurs ------> ethanol is formed making the drink alcoholic
- CO2 makes the drink fizzy + sharp flavour
- yeast is added to a source of sugar (fruit juice or germinated barley grains) and kept in warm conditions
- fermentation (yeast respires the sugar) occurs ------> ethanol is formed making the drink alcoholic
- CO2 makes the drink fizzy + sharp flavour