Respiration
External Respiration
The process by which organisms exchange gasess with their environment
Internal Respiration
The controlled release of energy from food by enzymes
Aerobic Respiration
The controlled release of energy from food using oxygen
C6H1206 + 6O2 = 6CO2 + 6H2O + Energy
Anaerobic Respiration
The controlled release of energy from food without the use of oxygen
Anaerobic Respiration is also known as fermentation
It is less efficient than aerobic respiration as glucose is only partially broken down
Lactic Acid Fermentation
Lactic acid fermentation occurs in some bacteria and fungi (anaerobes) and in mammal muscle when it is short of oxygen
When the supply of oxygen to a human muscle is not sufficient to meet the energy needs of the muscle, anaerobic respiration takes place.
Lactic Acid build-up causes cramp and muscular stiffness. It is broken down in the liver during rest.
Alcohol Fermentation
Takes place in some bacteria, fungi (eg yeast) and plants when they are deprived of oxygen.
Very little energy is released as glucose is only partially broken down.
Aerobic Respiration
Stage 1
- Takes place in the cytosol of the cell
- Does not use oxygen (anaerobic)
- Releases little energy (2 ATP molecules per glucose molecule)
- Converts glucose into two 3-Carbon molcules, known as Pyruvic Acid
- Converts 2ADP --> 2ATP
- Converts 2NAD+ --> 2NADH
- This stage is also known as glycolysis
Stage 2
- Takes place in the matrix of the mitochondria
- Requires oxygen
- Releases a large amount of energy
- Involves both Kreb's Cycle and the Electron Transport Chain
- Forms ATP and NADH
Each pyruvic acid moves into a mitochondrion where it loses a C02 and is converted into Acetyl Co-Enzyme A, a 2-Carbon molecule. Acetyl Co-Enzyme A then enters a series of reactions called Kreb's Cycle.
Kreb's Cycle
