Photosynthesis and respiration
The photosynthesis It is the biological process where solar energy is used to transform carbon dioxide and water into carbohydrates and oxygen. The cellular respiration is the biological process by which carbohydrates and oxygen are transformed to produce energy in the form of ATP.
| Photosynthesis | Breathing |
| Definition | Light-driven organic compounding process. | Process of using organic compounds to obtain chemical energy. |
| Where is it done? | Chloroplasts (plants and algae) Plasma membrane (cyanobacteria) | Cytoplasm and mitochondria (eukaryotes) Plasma membrane (bacteria, archaea) |
| Who do it? | Photoautotrophic organisms: - Plants
- Algae
- Cyanobacteria
| Most living organisms: - Plants
- Animals
- Mushrooms
- Protozoa
- Bacteria
|
| What produces? | - Glucose (C6H12OR6)
- Oxygen Otwo
| - Carbon dioxide (COtwo)
- Water (HtwoOR)
- ATP
|
| Phases | - Light dependent
- Independent of Light
| - Glycolysis
- Krebs cycle
- Oxidative phosphorylation
|
| Electron transport chain | Photosystems I and II | Complexes I, II, III and IV |
| Types | - C3 photosynthesis
- C4 photosynthesis
- CAM photosynthesis
| - Aerobic respiration
- Anaerobic respiration
|
| Importance | - Carbohydrate production.
- Release of oxygen.
- Transformation of light energy into chemical energy.
| - Obtaining energy from carbohydrates.
- Carbon dioxide release for the greenhouse effect.
|
| Equation | 6COtwo + 6HtwoO + light → C6H12OR6 + 6thtwo | C6H12OR6+6thtwo→ 6COtwo+6HtwoO + ATP |
What is photosynthesis?
Photosynthesis is the process of transforming carbon dioxide and water to form sugars and oxygen. In this process, the energy of light is transformed into chemical energy..
The organisms that carry out photosynthesis are photoautotrophs: plants, algae, and cyanobacteria. In plants, photosynthesis takes place in the leaves, where chloroplasts are found. In cyanobacteria, the photosynthetic machinery is found in the plasma membrane.
The general chemical reaction of photosynthesis is summarized in the following equation:
6COtwo + 6HtwoO + light → C6H12OR6 + 6thtwo
where from carbon dioxide, water and light energy glucose is obtained and the oxygen that is released into the atmosphere.
Phases of photosynthesis
Photosynthesis reactions are classified into two phases:
- Light dependent phase: the energy derived from sunlight activates an electron in chlorophyll, which enters the electron transport chain of the chloroplast and produces ATP, oxygen and reducing agents ...
- Phase independent of light (or dark phase): carbon fixation reactions are carried out, where ATP and reducing agents produced in the light phase to convert carbon dioxide into sugar.
Types of photosynthesis
Plants can be differentiated by the type of photosynthesis they perform:
- C3 photosynthesis: in most plants carbon dioxide binds the three-carbon molecule phosphoglyceric acid.
- C4 photosynthesis: in corn and sugar cane, carbon dioxide binds to the four-carbon molecule oxaloacetic acid.
- CAM photosynthesis: found in succulent plants.
What is cellular respiration?
The breathing It is the cellular process that allows the energy stored in carbohydrates to be used using oxygen. The products are carbon dioxide, ATP and water. ATP is used for metabolic reactions while COtwo exits the cell and is then eliminated.
Most living organisms carry out cellular respiration:
- in plants, animals, fungi and protozoa it is carried out in the mitochondria and cytoplasm.
- In some bacteria and archaea it is carried out in the plasma membrane.
The general chemical reaction of respiration is summarized in the following equation:
C6H12OR6 + 6thtwo → 6COtwo + 6HtwoOR
where glucose reacts with oxygen resulting in ATP, carbon dioxide, and water.
Phases of cellular respiration
Cellular respiration reactions can be classified into three phases:
- Glycolysis: it is the first route of decomposition of glucose to obtain energy, pyruvate and reducing agents.
- Krebs cycle or citric acid cycle: pyruvate enters a cycle of enzymatic reactions to break down into carbon dioxide and produce ATP and reducing agents.
- Oxidative phosphorylation: it is the metabolic pathway that captures electrons and reducing agents to produce more ATP.
Types of cellular respiration
Respiration can be of two types depending on the compound that accepts electrons:
- Aerobic respiration: oxygen Otwo is the molecule that accepts electrons to transform into water (HtwoOR).
- Anaerobic respiration: in environments where O is not presenttwo, some microorganisms (bacteria and archaea) use other molecules as electron acceptors, for example sulfate and nitrate.
Relationship between photosynthesis and cellular respiration
Photosynthesis and respiration are complementary processes:
- Photosynthesis uses solar energy to produce organic compounds; respiration uses organic compounds to obtain chemical energy.
- Organic compounds from photosynthesis serve as food for non-photosynthetic organisms.
- Carbon dioxide is transformed into organic compounds by photosynthesis; organic compounds are transformed into carbon dioxide by respiration.
- In photosynthesis oxygen is released which is then used in respiration.
- Photosynthesis and respiration are part of the biological carbon cycle.
- Both processes use chains of electron transporters to capture the energy needed for other reactions..
You may be interested in seeing Autotrophic and heterotrophic organisms
References
Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P. (2008) Molecular Biology of the Cell 5th ed. Garland science.
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