Photosynthesis Chapter 3 Section 3

Photo-light synthesis- to put together All living things get their energy either directly or indirectly from the sun Autotrophs- use the sun’s energy directly Heterotrophs- use the sun’s energy indirectly

Chemical equation: (Glucose) 6 CO2 + 6H2O + sun-C6H12O6 + 6 O2 Arrow means “yields

definition In photosynthesis plants and some other organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars

2 Parts to photosynthesis: 1. capture of the sun’s energy by chlorophyll (pigments) 2. conversion of the sun’s energy to usable chemical energy in the form of glucose

Stage 1: Light Dependant Reaction Occurs in the chloroplasts in the leaves Green pigment called chlorophyll absorbs the light and converts it to chemical energy (ATP- adenosine triphosphate) The energy is then used in the second part of photosynthesis

Stage 2: Light Independent Reaction Captured energy is used to make sugars. Occurs inside the chloroplasts Water (from roots) & CO2 (from stomata) undergo a complex series of chemical reactions to ultimately produce a 6 Carbon sugar called glucose O2 is given off as a by-product through the stomata

What happens to the sugar? Plant cells break down sugar to use as energy to fuel life functions Some are converted into other molecules like cellulose (starch, used in cell parts) Others are stored to be used for food later (starch, used for food ex. Potato)