Photosynthesis

Photosynthesis Overview

  • Photosynthesis is the process five which plants, algae, and certain bacteria convert light energy into chemical energy.

Light-Dependent and Light-Independent Reactions

  • Photosynthesis consists of two main stages – light-dependent reactions and light-independent reactions whose energy is collated into ATP and NADPH respectively.

Light-Dependent Reactions

  • The light-dependent reactions take place within the thylakoid membranes of the chloroplasts where light energy is captured and transferred to electron carriers.

Formation of ATP

  • During these light-dependent reactions, water is split into oxygen and hydrogen, a process commonly referred to as photolysis. This leads to the creation of ATP (adenosine triphosphate), the main cellular energy currency.

Light-Independent Reactions

  • The light-independent reactions, also known as the Calvin cycle, occur in the stroma of the chloroplasts where ATP and NADPH are used to convert carbon dioxide into glucose.

Glucose: The Energy-Providing Molecule

  • The glucose produced through photosynthesis acts as a source of stored energy for organisms.

Chlorophyll: The Essential Pigment

  • The pigment chlorophyll, found within the chloroplasts, absorbs light energy, which is necessary for photosynthesis to occur. The most crucial wavelengths for photosynthesis are in the blue-violet and red parts of the light spectrum.

Significance of Photosynthesis

  • Photosynthesis is vital because it provides oxygen and acts as the base of most food chains, providing energy for life on Earth.

Chemical Reactions

  • The overall chemical reaction for photosynthesis is: 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2.

Role of the Sun

  • The sun plays a crucial role in photosynthesis by providing the light energy that is converted into chemical energy. This energy is stored to power growth, reproduction and other vital plant processes.

Importance of Water and Carbon Dioxide

  • Water and carbon dioxide are essential reactants in the process of photosynthesis. Water is a vital source of hydrogen in glucose formation while carbon dioxide supplies the carbon.

Chloroplasts: Power Centres

  • The chloroplasts, which host the entire chemosynthetic process, are frequently referred to as the “factories of the cell.”
  • The structure of chloroplasts, equipped with all necessary machinery such as chlorophyll and enzymes, participate in efficient photosynthesis to meet plant energy demands.