Photosynthesis and Cellular Respiration Notes

Photosynthesis

• Photosynthesis is one of the most important chemical reactions on our planet.
• Photosynthesis is the process of changing light energy to chemical energy.
• The energy is stored as sugar.
• Photosynthesis occurs in plants and some algae.
• Photosynthesis takes place in the chloroplasts.
• Chloroplasts contain chlorophyll, the green pigment in plants.
• Plants capture light energy and use that energy to make glucose.
• Oxygen is also released in this reaction, which animals need to survive.
• Carbon dioxide ($CO_2$) enters the leaf through holes called stomata.
• $CO_2$ combines with the stored energy in the chloroplasts through a reaction to make glucose.
• The sugar (glucose) is moved through tubes in the leaf to the roots, stems, and fruits of the plants.
• Some of the sugar is used right away by the plant for energy.
• Some sugar is stored as starch, and some is built into plant tissue.
• We cannot make our own food (glucose, energy); we must get our food from plants.
• Plants are the first step in the food chain.
• Oxygen released during photosynthesis is necessary for all living things.

Photosynthesis Equation

$6CO<em>2 + 6H</em>2O + \text{Sunlight} \rightarrow C<em>6H</em>{12}O<em>6 + 6O</em>2$

• Carbon dioxide + water + energy glucose + oxygen

Cellular Respiration

• Cellular respiration is the release of chemical energy for use by cells.
• Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism must transform the chemical energy into a form that can be used by the organism.
• Cellular respiration is the breakdown of glucose molecules to release energy that takes place in all living things.
• It occurs in the mitochondria of eukaryotic cells.
• It occurs in the cell membrane and cytoplasm of prokaryotic cells.