Cell Processes

Photosynthesis and Respiration

Photosynthesis

• Nearly all living things get their energy either directly or indirectly from energy of sunlight.

Autotrophs

An organism that makes its own food.

Heterotrophs

• Organism that cannot make its own food.

Two Stages of Photosynthesis

1. Capturing the sun’s energy Chlorophyll- the green pigment in

plants that captures the sun’s energy. Found in the chloroplasts of a plant cell.

2. Using Energy to Make Food

With water and carbon dioxide to make glucose (sugar) to use as food.

Equation for Photosynthesis

6CO2 + 6H2O------------> C6H12O6 + 6O2

Respiration

• During respiration cells break down simple food molecules such as sugar and release the energy they contain

• This occurs in the mitochondria of all cells.

Stage One

• In the cytoplasm, glucose is broken down into smaller molecules and a small amount of energy is released.

Stage Two

• In the Mitochondria, the smaller molecules combine with oxygen to produce water and carbon dioxide, this reaction releases a large amount of energy

You can think of photosynthesis and respiration as opposite processes