What is plant photosynthesis

Photosynthesis is the process of obtaining energy from plants, algae and certain bacteria through sunlight. It is also called the chlorophyll function.

Technically, the photosynthesis process converts carbon dioxide (CO2) and water (H2O) into glucose (C6h12EITHER6), that is, it converts inorganic substances into organic substances.


Organisms that possess the ability to photosynthesis are called autotrophs while they do not depend on other living beings for food. Within this category, they specifically classify as photoautotrophsThey get energy from sunlight.

The word photosynthesis is of Greek origin. photos which means “light” syn which is equivalent to “with” and thesis that expresses “conclusion or position”.

elements of photosynthesis

The elements that participate in photosynthesis can be separated into: external, internal and products.

The external elements are:

  • Solar energy.
  • carbon dioxide (CO2).
  • Water (H)2EITHER).
  • Mineral salts.

The internal elements of the organisms are:

  • chloroplasts: are polymorphic structures of the cells of photoautotrophic organisms. They are responsible for executing the process of photosynthesis.
  • Chlorophyll: are molecules present in chloroplasts that are responsible for capturing solar energy.
  • stomata: are small pores or openings on the surface of plants and algae that capture CO2.
  • Estate: They are the organs of plants and algae that allow them to capture water.
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The products of photosynthesis are:

  • Glucose (C)6h12EITHER6): It is the main product of photosynthesis, and provides energy for plants, algae and bacteria to live. It is also the main source of energy for all those beings that cannot carry out photosynthesis, such as animals, fungi, protozoa, some bacteria and archaea.
  • Oxygen (O2): it is a by-product of photosynthesis, released abroad by most photoautotrophic organisms.

phases of photosynthesis

The process of photosynthesis occurs in two phases or stages, called the light phase and the dark phase.

Light or photochemical phase

This phase is photodependent, since it develops only when there is light. During the light phase, the organism captures sunlight through the chlorophyll present in the chloroplasts. Thanks to this, chemical energy and reducing power are accumulated. Likewise, it is in this phase where oxygen is usually released into the environment (in organisms of oxygenic photosynthesis).

The process occurs in the thylakoid membrane of chloroplasts. The light energy stimulates the production of energetic power in the form of adenosine triphosphate (ATP) and reducing power in the form of nicotinamide adenine dinucleotide phosphate (NADPH).

Dark phase or carbon fixation phase

Also called the Calvin cycle, the dark phase is a photoindependent phase, since it does not require the presence of light. In this occurs the transformation of inorganic substances into organic ones.

The process is carried out as follows: organisms capture carbon dioxide through stomata, which are like small pores that allow breathing.

They also receive water and mineral salts from the earth through their roots. Once the dioxide and water are absorbed, solar energy separates and synthesizes them.

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The dark phase occurs in the stroma of the chloroplasts, where the ATP and NADPH energy obtained in the light phase encourage the transformation of matter.

See also: Chlorophyll, Chloroplasts, and Autotrophic nutrition.

types of photosynthesis

Photosynthesis can be classified according to different criteria.

According to the production (or not) of oxygen

  • Oxygenic photosynthesis: is one in which oxygen is released as a by-product. It takes place in plants, algae, and a specific type of bacteria called cyanobacteria. In all these organisms, water acts as an electron donor. This means that oxidation of water is carried out.
  • Anoxygenic photosynthesis: It is one in which certain photoautotrophic organisms transform light energy into chemical energy but do not produce oxygen. This is because they capture light with bacteriochlorophyll molecules instead of chlorophyll. For example, purple sulfur bacteria, acidobacteria or heliobacteria, among others.

According to the fixation of carbon dioxide (CO2)

  • C3 Photosynthesis: is when the CO2 It fixes on three-carbon molecules. It is the characteristic mechanism of most plants.
  • C4 Photosynthesis: is when the CO2 It fixes on four-carbon molecules. This mechanism is seen, for example, in sugarcane.
  • CAM Photosynthesis: It is the one that occurs in succulent plants. CAM stands for Crassulaceae Acid Metabolism.

importance of photosynthesis

Photosynthesis is important for life and for the respiration of all aerobic living beings, since the process allows fixing carbon dioxide from the atmosphere and releasing oxygen.

Life on our planet is preserved thanks to the photosynthesis carried out by plants in the terrestrial environment and algae in the aquatic environment. They are in charge of purifying the environment that living beings breathe, which would otherwise poison us.

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In addition, plants and algae constitute the basic diet of a large part of the food chain (herbivorous and omnivorous beings). Therefore, the beginning of all life on Earth is directly and indirectly related to the process of photosynthesis.

See also:

  • Plant cell.
  • autotrophic organisms.
  • types of breathing