Students will be able to identify the process of photosynthesis

• Photosynthesis is the process by which green plants, algae, and some bacteria make their own food.

• It happens in the chloroplasts of plant cells, which contain the green pigment chlorophyll.

• Plants use sunlight, carbon dioxide (CO₂), and water (H₂O) to produce glucose (sugar) for energy and oxygen (O₂) as a by-product.

“Plants take in sunlight, carbon dioxide, and water → make sugar for food and give out oxygen.”

6CO2+6H2O+light→C6H12O6+6O26CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂

Key Ingredients (Reactants):

1. Sunlight – provides energy.

2. Water (H₂O) – absorbed through roots.

3. Carbon dioxide (CO₂) – taken in through tiny pores in leaves called stomata.

Products:

1. Glucose (C₆H₁₂O₆):

   • Plant food, used for growth and energy.

   • Stored as starch in roots, stems, and leaves.

2. Oxygen (O₂):

   • Released into the air – essential for humans and animals to breathe.

   
   

6CO2​+6H2​O+Light Energy→C6​H12​O6​+6O2​

• 6CO2​ (carbon dioxide) and 6H2​O (water) are the reactants.

• C6​H12​O6​ (glucose) and 6O2​ (oxygen) are the products.

• Light energy from the sun powers the whole process.

Photosynthesis occurs inside specialized organelles in plant cells called chloroplasts.

Stage 1: The Light-Dependent Reactions

• What it is: The "photo" part of photosynthesis, where light energy is captured and converted into short-term chemical energy.

• Location: This stage occurs in the thylakoid membranes within the chloroplasts.

• What happens:

  • Chlorophyll, the green pigment in plants, absorbs light energy from the sun.

  • This energy is used to split water molecules (H2​O). This process, called photolysis, releases oxygen (O2​) as a waste product, which is what we breathe! 🌬️

  • The energy from the sun is also used to create two important energy-carrying molecules: ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate). These molecules act like rechargeable batteries, storing energy to be used later.

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Stage 2: The Light-Independent Reactions (Calvin Cycle)

• What it is: The "synthesis" part of photosynthesis, where the chemical energy from the first stage is used to build glucose. It's often called the Calvin cycle.

• Location: This stage takes place in the stroma, the fluid-filled space surrounding the thylakoids inside the chloroplast.

• What happens:

  • The plant takes in carbon dioxide (CO2​) from the atmosphere through tiny pores in its leaves called stomata.

  • Using the energy from the ATP and NADPH produced in the light-dependent reactions, the plant "fixes" the carbon from CO2​. This means it converts inorganic carbon from the atmosphere into organic carbon compounds.

  • Through a series of complex reactions, these carbon compounds are rearranged and ultimately used to build glucose (C6​H12​O6​), a stable sugar molecule that the plant can use for energy or store for later.

1. A plant's leaves take in carbon dioxide from the air.

2. The plant's roots absorb water from the soil.

3. The leaves contain a green substance called chlorophyll.

4. Chlorophyll captures sunlight for energy.

5. Using the sunlight, the plant turns carbon dioxide and water into glucose.

6. Glucose is a type of sugar that the plant uses for food.

7. As a final step, the plant releases oxygen back into the air.

• Provides oxygen for living things.

• Produces food (plants form the base of all food chains).

• Helps regulate the Earth’s atmosphere by absorbing carbon dioxide.

• Supports life on Earth – without photosynthesis, life would not exist.

Fun Facts:

• About 70–80% of Earth’s oxygen comes from photosynthesis in the ocean (algae, not just land plants).

• The Amazon rainforest is called the “lungs of the Earth.”

• Photosynthesis not only feeds plants—it feeds us indirectly, since we eat plants (and animals that eat plants).