Give the conditions necessary for the second phase of aerobic respiration
Answers
The stages of aerobic respiration
Stage one
Glucose in the cytoplasm of cells is broken down into two molecules of pyruvate. This releases enough energy to produce two molecules of ATP for every molecule of glucose that is broken down.
The breakdown reactions that occur are catalysed by specific enzymes. If these enzymes are not present or functional then the reactions will not occur, so the breakdown of glucose is controlled by enzymes.
Glucose becomes two pyruvate and releases energy. The energy is combined with two ADP and two Pi to create two ATP.
This stage does not require oxygen. If oxygen is available to the cell then the pyruvate molecules can be further broken down in stage two to release more energy and produce a greater quantity of ATP.
Stage two
A pyruvate molecule enters the mitochondria and is broken down in the presence of oxygen to produce carbon dioxide and water. Enough energy is released from each pyruvate molecule to produce a large number of ATP molecules.
As in stage one, the breakdown reactions in this process are catalysed by specific enzymes.
Pyruvate breaks down into carbon dioxide, and water (with the addition of oxygen). The released energy is combined with 18 ADP and 18 Pi to create 18 ATP.
Oxygen does not react directly with molecules of pyruvate. It is involved in the final step of the breakdown.
If oxygen is not available then only two ATP are produced.
Cells that have a high-energy demand such as nerve cells and muscle cells contain a large number of mitochondria to maximise ATP production by aerobic respiration.
A muscle cell labelling cell membrane, myofibril and mitochondria.
A muscle cell contains myofibrils, proteins that make the cell contract, and high numbers of mitochondria to produce the large quantity of ATP molecules required.
In this video science presenter Jon Chase describes aerobic respiration as the release of energy from glucose in the presence of oxygen.
Aerobic Respiration
Explanation:
- The first stage of the aerobic and an-aerobic and aerobic respiration is glycolysis
- In the glycolysis, the glucose molecule separates into two three carbon compound pyruvic acid. In the second stage,the pyruvic acid undergoes incomplte oxidation i.e. fermentation
- Aerobic respiration second stage occurs in the internal compartment of the mitochondria
- During the responses, pyruvate is changed over to acetyl-CoA which enters the Krebs Cycle. For two pyruvates, the two ATP and ten coenzymes structure