Photosynthesis is the process by which plants use

� Photosynthesis is the process by which plants use the sun’s energy to convert water and carbon dioxide into sugars. � Read “Energy” p. 327 – 329 � Take Notes!

� Energy is the ability to do work. � Kinetic energy is the energy of motion � Potential energy is energy that is stored due to an object’s position or arrangement. � Energy can be converted from one form to another. � Different types of energy – chemical, light, electrical, mechanical, thermal

� Organic molecules have a form of potential energy called chemical energy � Chemical energy has the potential to do work due to the arrangement of the atoms within the molecules. � The rearrangement of atoms during chemical reactions releases the potential energy, and the energy is then available to do work.

� Photosynthesis is the process by which plants use the sun’s energy to convert water and carbon dioxide into sugars. � Light is the only source of energy for plants! � Plants convert light energy into chemical energy -> Photosynthesis � Recall that light is energy � Different colors of light have different wavelengths and different amounts of energy. � Red light = low energy � Blue light = high energy

Light is a form of energy called Electromagnetic energy.

�A substance’s color is due to chemical compounds called pigments. � When light hits an object the wavelengths can be transmitted, absorbed, or reflected.

� Chloroplasts contain pigments called Chlorophyll a, Chlorophyll b, and Carotenoids. � Each pigment absorbs different wavelengths of light.

� Notice that chloroplasts absorb blue-violet and red-orange light very well. � The chloroplasts convert the absorbed light energy into chemical energy. � Why are leaves green? � Why do leaves change colors in the fall? � Complete Stop & Think #1 -4 p. 329

� Read “Making Carbon Compounds” p. 330 -333 � Take notes! � Read “Energy Currency of Cells” p. 333 � Take Notes.