Definition of Photosynthesis: Stages, Terms, Factors, and Benefits

Photosynthesis is – Photosynthesis is a natural phenomenon that occurs in plants to get their food substances. This process is also very necessary so that plants or plants can develop and survive in all conditions. Every plant that lives on planet Earth can then generally carry out photosynthesis. In addition, this process also requires sunlight to convert carbon dioxide and water into carbohydrates.

According to a number of experts, photosynthesis is a reaction that will occur in plants in order to obtain glucose and oxygen with the help of sunlight. In short, this process is then the same as how other living things get energy intake.

Lessons about photosynthesis are usually given when someone enters junior high school (SMP). However, there is nothing wrong if this material is studied again because it is closely related to everyday life. Compiled from a number of sources, below is an explanation of what photosynthesis is and how this natural process occurs in plants. So, see the explanation about photosynthesis until it’s finished, Readers.

Definition of Photosynthesis

Photosynthesis as a natural event that occurs repeatedly in plants. Leaves are the main organ in plants where photosynthesis takes place. Apart from plants, photosynthesis then becomes a natural process that plays an important role in the life of organisms, such as in humans and animals. This is because when the process of photosynthesis occurs, it will produce oxygen which is needed by living things to breathe.

After that, photosynthesis will also help recycle carbon dioxide (CO2) produced in the respiratory system. That way, air pollution can be reduced thanks to photosynthesis.

In the Big Indonesian Dictionary (KBBI), the word photosynthesis means the utilization of light energy in plants or bacteria to then convert carbon dioxide and water into carbohydrates. In the process, photosynthesis will then result in net photosynthesis if the amount of this photosynthetic product has been reduced by respiration. Materials regarding photosynthesis are also often discussed in plant physiology.

By knowing this knowledge, we can know more deeply how important sunlight is in the process of photosynthesis, especially in producing carbohydrates from an inorganic raw material in the form of water and carbon dioxide. Later, these carbohydrates will then become nutrients as well as a source of energy for plants. These carbohydrates will be stored as food reserves. When plants are consumed by humans or by animals, there will be a transfer of energy.

Photosynthesis Process

In the process, this chemical change then really needs these 4 things, namely water, carbon dioxide, chlorophyll, and sunlight. The following is the process of photosynthesis that you need to know:

  1. Plants will obtain water from the soil which is then absorbed by the roots, and from these roots it is distributed using a transportation system, namely xylem tissue and phloem tissue which are then distributed to all plant organs including leaves.
  2. Carbon dioxide will be obtained from the air which then enters through the stomata. The location of these stomata is on the underside of the leaf.
  3. Then, photosynthesis occurs in the leaf area. This photosynthesis process will also occur when the chlorophyll in the leaves has captured sunlight, which is then used to convert water and carbon dioxide into sugar and oxygen.
  4. Sugar produced from photosynthesis can be directly used by plants, or can be stored in other organs in plants, for example in fruit.
  5. In addition to sugar, the oxygen produced will later exit through the stomata and then into the air. This oxygen is also used by humans and animals to breathe.
  6. Through polymerization reactions, the glucose or sugar produced through this process will be arranged into a starch or starch substance. This starch substance will then be stored in the roots of plants

The Occurrence of Photosynthesis

According to the Supercomplete Middle School Biology book , green plants will then obtain food by producing it themselves. This process is then called photosynthesis. Green plants are also producers which can then convert inorganic substances into organic ones. Considering that only green plants can carry out photosynthesis, animals and humans then need these plants to be used as their own food.

As mentioned above, photosynthesis can then only occur in an organism that has chlorophyll. Chlorophyll as a plant pigment found in chloroplasts. This natural green dye then functions to absorb energy from sunlight. Humans can also experience the health benefits of chlorophyll by consuming a variety of green leafy vegetables, for example, in spinach or wheatgrass .

This process of photosynthesis then consists of two series which are divided according to the need for light and where it occurs. The following is a complete explanation of the series of photosynthetic processes in plants and organisms that have natural green pigments:

Light reaction

In the light reaction there is a hill reaction which then really needs light in the process of making sugar and oxygen. The light energy captured by chlorophyll functions as a breaker for water molecules. This splitting of water molecules is also known as photolysis.

Meanwhile, different types of chlorophyll pigments can only absorb wavelengths with different magnitudes of photons (light energy). The grana are where the light reactions take place. These grana are stacks of thylakoids. The light energy in the grana will then help accelerate the release of electrons from the photosystems inside the thylakoid membrane.

Thylakoids, proteins, and other molecules in the leaf cells will then form a photosystem. The photosystem is the site of hundreds of photosynthetic pigment molecules. This photosystem is divided into two, namely photosystem 1 and photosystem II. Then, the two will work together to produce ATP and NADPH2 as the main products of the light reactions.

Dark Reaction

The dark reaction is known as the Calvin-Benson cycle. In the dark reaction or in the Calvin reaction, sunlight is not required in the process of producing sugar and oxygen. This dark reaction phenomenon then occurs after the light reaction.

The dark reaction is the process by which ATP and NADPH are fertilized by CO2 and then become sugar. The stroma is also where the dark reactions take place. In the stroma fixation, reduction, and regeneration occur. The phases that occur in the stroma, namely:

  • CO2 binding (fixation).
  • reduction
  • Formation of RuBP (Ribulose Bisphosphate).

This dark reaction is then divided through several processes, including carbon dioxide which is bound by RuBp to give rise to phosphoglycerate (PGA). PGA is reduced giving birth to PGAL (phosphoglyceraldehyde) . PGAL will then be regenerated into glucose and RuBp.

Conditions for the Occurrence of Photosynthesis

The place where photosynthesis occurs is in the leaves. Then, so that plants can produce carbohydrates more quickly in the photosynthesis process, there are a number of conditions that must then be met, such as the following:

  1. This leaf consists of cells that are arranged regularly so that sunlight can then be received efficiently.
  2. These regularly arranged cells must contain chloroplasts within them.
  3. Between the cells that are arranged in an orderly manner, there are spaces between the cells so that air and the outside can enter through the spaces between the cells.
  4. These tightly arranged cells must be protected by epidermal tissue so that they are not scattered later.

Factors Affecting Photosynthesis

The success of plants and autotrophic organisms in a process of making food through the process of photosynthesis is influenced and requires several factors. As for the factors of photosynthesis, among others?


Light as a main component so that photosynthesis can take place properly:

Light intensity

Each plant has different light requirements. C3 type plants (ie legumes, cotton, soybeans, potatoes and wheat) have very low light tolerance, so when they are exposed to high light intensity, they will not increase their photosynthetic intensity. Meanwhile, C4 plants (sugarcane, corn, and sorghum) have very high light tolerance. At high light intensity it will then help increase the intensity of photosynthesis.

Light Wavelength

Each color spectrum then has a different wavelength. However, chlorophyll can absorb more red and blue colors, because the wavelength of light is very effective.


All plants will require different temperatures. For C3 plants, the optimal temperature then needed is around 20-26℃. Meanwhile for C4 plants the optimal temperature needed to photosynthesize is around 35-40℃. When the plant is mature, all the tissues in the plant or plant will then be formed more perfectly, so that it can help increase the effectiveness and rate of the photosynthesis process.

Carbon Dioxide (CO2) and Oxygen (O2) Concentrations

Carbon dioxide will greatly affect a photosynthesis. The higher the concentration of carbon dioxide in the air, the rate of photosynthesis will increase. In contrast to carbon dioxide, the more O2 concentration, the lower the intensity of photosynthesis.

Water and Nutrient Content

The process of photosynthesis will then be disrupted if a plant lacks water. Likewise with abundant water, this will also interfere with the process of photosynthesis. Chlorophyll also really needs the elements Mg (magnesium) and N (nitrogen). When these two elements are deficient, the rate of photosynthesis will decrease.

Benefits of Photosynthesis

The benefits of the process of photosynthesis and the chemical processes that occur in autotrophic organisms are not only beneficial for plants, but also beneficial for all living things. Some of the benefits of photosynthesis that you need include:

Producing Oxygen for Living Things

In the process of photosynthesis, plants will also help remove by-products, including oxygen. This oxygen itself is needed by living things to breathe. In addition, when this chemical change occurs, plants will then absorb carbon dioxide that comes from pollution. When carbon dioxide is absorbed, the air around the plants will then feel cleaner and fresher.

Forming Fruits and Tubers in Plants

Fruits and tubers are food reserves resulting from this chemical process. Fruits and tubers can also be used by humans and animals as a food source. These fruits and tubers contain vitamins and compounds that are beneficial to the human body.

Produces Glucose

Besides oxygen and fruit, there is also glucose. Glucose in plants is then used as fuel in building other food substances, such as fat or protein. Both of these substances are needed in animals and humans, especially protein is also very good for the body. This is because protein can repair cells and help boost human immunity.

Humidify the Air in the Surrounding Environment

Natural 10% air humidity comes from plants. This increased humidity will then have an effect on humans, namely a calming effect, overcoming fatigue, and making sleep more restful.

Producing Foodstuffs

The main function of a photosynthetic process, is its ability to produce food. For example, fruit, tubers and glucose. The content of nutrients in this plant itself is very useful for consumption by humans and animals. Therefore, the ability of plants to convert sunlight energy into chemical energy (food substances) is then always a link in a food chain.


Based on all the explanations above, it can be concluded that photosynthesis is a process of compiling simple compounds to become complex compounds, in plant parts which then contain chlorophyll.

The process of photosynthesis will also help produce the main product in the form of carbohydrates which are stored as a food reserve including fruit. This process will also really need the help of sunlight. When fruit is eaten by other living things, a phenomenon of energy transfer has occurred.