6.2 Cells and Energy Photosynthesis is a chemical reaction that takes place in the chloroplasts of plant cells. During photosynthesis, plants use the energy of sunlight to produce energy-rich molecules called carbohydrates (ex. glucose). In photosynthesis, plants take in carbon dioxide and water and release glucose and oxygen wastes.

6.2 Cells and Energy Chloroplasts are where photosynthesis occurs. Chloroplasts work much like solar cells found in calculators.

Review What is photosynthesis? Photosynthesis a chemical reaction that takes place in the chloroplasts of plant cells and produces carbohydrates. Which organelle is responsible for photosynthesis in plant cells? The chloroplast is responsible for photosynthesis.

6.2 Light and color The Sun provides Earth with a steady source of light. Your eyes see sunlight as white light, but it is really made up of different colors of light. A clear prism can split white light into a rainbow of color.

6.2 Light and color Light is part of a collection of waves known as the electromagnetic spectrum. Waves can be described by their wavelength (length from peak to peak), and their energy.

6.2 Light and color Color is how we experience the energy of light. The color that we see is actually being reflected by the object, all other colors are absorbed.

Review Is the color you see reflected or absorbed by the object? An object is a certain color because of the light that it reflects. For instance a shirt is blue because it reflects the blue wavelength of visible light.

6.2 Chlorophyll A pigment is a molecule that absorbs some colors of light and reflects others. Chlorophyll is the main pigment used in photosynthesis.

6.2 Chlorophyll Chlorophyll absorbs mostly blue and red light, and reflects green light. This is why most plants look green.

Review What wavelengths of color does chlorophyll absorb? Chlorophyll absorbs red and blue wavelengths of light.

6.2 Cellular respiration Cellular respiration is a chemical reaction that occurs in all living things. Cells use oxygen and glucose to produce carbon dioxide, water, and energy.

6.2 Cellular respiration In most eukaryotic organisms, cellular respiration takes place in the mitochondria of cells. During cellular respiration, energy is stored in a molecule called ATP while some energy is released as heat.

Review In what organelle does cellular respiration take place? Cellular respiration takes place in the mitochondria of the cells.

6.2 Comparing photosynthesis and respiration The chemical equations of photosynthesis and respiration have an interesting relationship. The reactants in photosynthesis are the products in cellular respiration! The reactants in cellular respiration are the products in photosynthesis!

Review How are photosynthesis and cellular respiration related? The wastes in photosynthesis are used to create energy in cellular respiration and the wastes in cellular respiration are used to create energy in photosynthesis.