AP Biology / Freshman Biology
Photosynthesis Complete Study Guide +
Exam Prep
1. Overview of Photosynthesis
Photosynthesis is the process by which plants convert light energy from the sun into
chemical energy stored in glucose (sugar).
This process allows plants to create their own food and provides oxygen for other living
organisms.
Photosynthesis mainly occurs in the chloroplasts found in plant cells, especially in the leaves.
2. Photosynthesis Equation
Carbon Dioxide + Water + Light Energy → Glucose + Oxygen
CO₂ + H₂O + Light → C₆H₁₂O₆ + O₂
This means plants take in carbon dioxide from the air and water from the soil. Using
sunlight, they produce glucose (energy) and release oxygen into the atmosphere.
3. Where Photosynthesis Happens
Photosynthesis occurs in a plant cell structure called the chloroplast.
Important parts of the chloroplast:
, Chlorophyll
● Green pigment that captures sunlight
● Found inside chloroplasts
● Responsible for the green color of plants
Thylakoids
● Membrane structures where the light reactions occur
Stroma
● Fluid area where the Calvin Cycle occurs
4. Two Main Stages of Photosynthesis
Stage 1: Light-Dependent Reactions
These reactions require sunlight and occur in the thylakoid membranes.
What happens during this stage:
● Chlorophyll absorbs sunlight
● Water molecules split
● Oxygen is released
● Energy molecules (ATP and NADPH) are produced
Key result:
Energy from sunlight is converted into chemical energy.
Stage 2: Calvin Cycle (Light-Independent Reactions)
This stage occurs in the stroma of the chloroplast.
What happens:
● Carbon dioxide enters the cycle
● Energy from the light reactions is used
● Glucose is produced
Photosynthesis Complete Study Guide +
Exam Prep
1. Overview of Photosynthesis
Photosynthesis is the process by which plants convert light energy from the sun into
chemical energy stored in glucose (sugar).
This process allows plants to create their own food and provides oxygen for other living
organisms.
Photosynthesis mainly occurs in the chloroplasts found in plant cells, especially in the leaves.
2. Photosynthesis Equation
Carbon Dioxide + Water + Light Energy → Glucose + Oxygen
CO₂ + H₂O + Light → C₆H₁₂O₆ + O₂
This means plants take in carbon dioxide from the air and water from the soil. Using
sunlight, they produce glucose (energy) and release oxygen into the atmosphere.
3. Where Photosynthesis Happens
Photosynthesis occurs in a plant cell structure called the chloroplast.
Important parts of the chloroplast:
, Chlorophyll
● Green pigment that captures sunlight
● Found inside chloroplasts
● Responsible for the green color of plants
Thylakoids
● Membrane structures where the light reactions occur
Stroma
● Fluid area where the Calvin Cycle occurs
4. Two Main Stages of Photosynthesis
Stage 1: Light-Dependent Reactions
These reactions require sunlight and occur in the thylakoid membranes.
What happens during this stage:
● Chlorophyll absorbs sunlight
● Water molecules split
● Oxygen is released
● Energy molecules (ATP and NADPH) are produced
Key result:
Energy from sunlight is converted into chemical energy.
Stage 2: Calvin Cycle (Light-Independent Reactions)
This stage occurs in the stroma of the chloroplast.
What happens:
● Carbon dioxide enters the cycle
● Energy from the light reactions is used
● Glucose is produced
