Photosynthesis Overview

Photosynthesis Overview

• Definition: Process by which plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of organic compounds
• Occurs in specialized organelles called chloroplasts, found in plant cells

Light-Dependent Reactions

• Light absorption by pigments such as chlorophyll and other accessory pigments
• Excitation of electrons, which are then transferred to electron acceptors
• Formation of high-energy molecules ATP and NADPH

Light-Independent Reactions (Calvin Cycle)

• Fixation of CO2 into organic compounds using ATP and NADPH produced in light-dependent reactions
• Regeneration of RuBP, the five-carbon sugar that binds CO2
• Production of glucose and other organic compounds

Equation

6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2

Factors Affecting Photosynthesis

• Light intensity and quality
• Temperature
• Water availability
• CO2 concentration
• pH

Importance of Photosynthesis

• Produces oxygen for the atmosphere
• Supports food chains and webs
• Provides energy and organic compounds for heterotrophic organisms
• Helps regulate Earth's climate

Photosynthesis Overview

• Photosynthesis is the process by which plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of organic compounds.
• This process occurs in specialized organelles called chloroplasts, found in plant cells.

Light-Dependent Reactions

• Light absorption occurs through pigments such as chlorophyll and other accessory pigments.
• Excitation of electrons takes place, which are then transferred to electron acceptors.
• High-energy molecules ATP and NADPH are formed.

Light-Independent Reactions (Calvin Cycle)

• CO2 is fixed into organic compounds using ATP and NADPH produced in light-dependent reactions.
• RuBP, a five-carbon sugar, is regenerated and binds CO2.
• Glucose and other organic compounds are produced.

Equation for Photosynthesis

• 6 CO2, 6 H2O, and light energy react to form C6H12O6 (glucose) and 6 O2.

Factors Affecting Photosynthesis

• Light intensity and quality impact photosynthesis.
• Temperature affects the rate of photosynthesis.
• Water availability influences photosynthesis.
• CO2 concentration affects photosynthesis.
• pH level affects photosynthesis.

Importance of Photosynthesis

• Oxygen is produced for the atmosphere through photosynthesis.
• Photosynthesis supports food chains and webs.
• It provides energy and organic compounds for heterotrophic organisms.
• Photosynthesis helps regulate Earth's climate.