PHOTOSYNTHESIS

INTRODUCTION All cells need energy. All cells get their energy in the form of chemical energy. Chemical energy is the energy stored in the bonds between atoms of every molecule. Cells must be able to release energy stored in the bonds of their food molecules.

INTRODUCTION The molecule used by most organisms as an energy source is glucose. Plants make their own glucose, while animals must consume food in order to obtain glucose.

PHOTOSYNTHESIS The source of energy for most organisms ultimately comes from the sun. During the process of photosynthesis, plants change the energy from the sun to the chemical energy (energy they can use) stored in the bonds of glucose molecules.

LOCATION Photosynthesis takes place in plant cells that contain chloroplasts, i.e. leaves. Chloroplasts contain chlorophyll, a light-absorbing pigment, that traps the energy in sunlight.

A CHEMICAL CHANGE Reactants Carbon dioxide (CO2) from the air Water (H2O) from the soil

A CHEMICAL CHANGE Chemical Reaction The energy in the chlorophyll (sunlight) causes the atoms in carbon dioxide and the water to recombine and become new substances

A CHEMICAL CHANGE Products Glucose (sugar) – plants keeps for its energy needs Oxygen (O2) – released in to the air

A CHEMICAL CHANGE Water + Carbon dioxide + Light energy Glucose + Oxygen

PHOTOSYNTHESIS GLUCOSE CHLOROPLAST OXYGEN WATER CARBON DIOXIDE LIGHT ENERGY OXYGEN WATER