KEY CONCEPT The overall process of photosynthesis produces sugars that store chemical energy. These diatoms are single-celled algae that use the process of photosynthesis to store chemical energy. Animals eat photosynthetic organisms such as plants and algae to get this chemical energy. Photosynthetic organisms also produce the oxygen that is required to release much of the chemical energy in sugars.

Photosynthetic organisms are producers. Producers make their own source of chemical energy. Plants use photosynthesis and are producers. Photosynthesis captures energy from sunlight to make sugars. Apply: Describe the importance of producers and photosynthesis.

Chlorophyll is a molecule that absorbs light energy. chloroplast leaf cell leaf In plants, chlorophyll is found in organelles called chloroplasts.

Photosynthesis in plants occurs in chloroplasts. Photosynthesis takes place in two parts of chloroplasts. grana (thylakoids) - Grana are the stacks of coin-shaped, membrane bound compartments called thylakoids. Stroma – is the fluid that surrounds the grans in side a chloroplast. chloroplast stroma grana (thylakoids)

The light-dependent reactions capture energy from sunlight. take place in thylakoids water and sunlight are needed (reactants) chlorophyll absorbs energy energy is transferred along thylakoid membrane then to light-independent reactions oxygen is released (product)

The light-independent reactions make sugars. take place in stroma needs carbon dioxide (reactant) from atmosphere use energy to build a sugar (product) in a cycle of chemical reactions

The equation for the overall process is: 6CO2 + 6H2O + sunlight C6H12O6 + 6O2 C6H12O6 granum (stack of thylakoids) thylakoid sunlight 1 six-carbon sugar 6H2O 6CO2 6O2 chloroplast 1 2 4 3 energy stroma (fluid outside the thylakoids) Summarize: How is energy from sunlight used to make sugar molecules?