Photosynthesis is the process in which green parts of plants use carbon dioxide and water in the presence of sunlight and chlorophyll to produce glucose as food and in this process, oxygen gas is released as a byproduct.
Chloroplasts are the sites of photosynthesis in plants and blue-green algae. All green parts of a plant, including the green stems, green leaves, and sepals – floral parts comprise chloroplasts which are the green-colored plastids that help with photosynthesis.
These cell organelles are present only in plant cells and are located within the mesophyll cells of leaves.
The chemical equation of photosynthesis can be represented as:
6CO2 + 6H2O → C6 H12O6 + 6O2.
Carbon dioxide + Water → Glucose + Oxygen
The Diagram of Photosynthesis
Refer to the photosynthesis diagram shows how plants make their food. In the photosynthesis process, green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
The key components and steps of the photosynthesis diagram:
Sunlight: Plants trap light energy with their leaves. Plants use the energy of the sun to change water and carbon dioxide into a sugar called glucose.
Chloroplasts: Chloroplasts are the plant organelle where photosynthesis takes place. Chloroplasts are chlorophyll-containing organelles found in plants, algae, and cyanobacteria. Photosynthesis occurs in chloroplasts. Chlorophyll is a green photosynthetic pigment within the chloroplast grana that absorbs light energy for photosynthesis. Chloroplast structures include:
- Membrane Envelope: contains inner and outer lipid bilayer membranes that act as protective coverings and keep chloroplast structures enclosed. The inner membrane separates the stroma from the intermembrane space and regulates the passage of molecules into and out of the chloroplast.
- Intermembrane Space: space between the outer membrane and inner membrane.
- Thylakoid System: internal membrane system consisting of flattened sac-like membrane structures called thylakoids that serve as the sites of conversion of light energy to chemical energy.
- Thylakoid Lumen: compartment within each thylakoid.
- Grana (singular granum): densely layered stacks of thylakoid sacs (10 to 20) that serve as the sites of conversion of light energy to chemical energy.
- Stroma: dense fluid within the chloroplast that lies inside the envelope but outside the thylakoid membrane. This is the site of the conversion of carbon dioxide to carbohydrates (sugar).
- Chlorophyll: a green photosynthetic pigment within the chloroplast grana that absorbs light energy.
Light-dependent reactions: The light reaction is also known as the photolysis reaction and takes place in the presence of light. It usually takes place in the grana of chloroplasts. The light reaction is the first stage of the photosynthesis process in which solar energy is converted into chemical energy in the form of ATP and NADPH. The protein complexes and the pigment molecules help in the production of NADPH and ATP.
Photosystem II: Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation.
Electron transport chain (ETC): Electron Transport Chain is a series of compounds where it makes use of electrons from electron carriers to develop a chemical gradient. It could be used to power oxidative phosphorylation. The molecules present in the chain comprise enzymes that are protein complexes or proteins, peptides, and much more.
Photosystem I: Photosystem I (PSI) is a multi-subunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport.
Production of ATP and NADPH: This is accomplished using two different photosystems in the light reactions of photosynthesis, one to generate ATP and the other to generate NADPH. Electrons are transferred sequentially between the two photosystems, with photosystem I acting to generate NADPH and photosystem II acting to generate ATP.
Calvin Cycle: Calvin cycle is also known as the C3 cycle. It is the cycle of chemical reactions where the carbon from the carbon cycle is fixed into sugars. It occurs in the chloroplast of the plant cell.
Glucose: Plants use the energy of the sun to change water and carbon dioxide into a sugar called glucose. Glucose is used by plants for energy and to make other substances like cellulose and starch.
Oxygen: Oxygen is a byproduct of photosynthesis and, correspondingly, carbon dioxide is the byproduct of respiration. Trees are often credited as the major oxygen generator for the planet, but that would be false. Most of the planet is covered with water and the collective photosynthesis of lowly algae is the true oxygen machine.
Photosynthesis Diagram
