Cell Biology

Chapter Eight: Cell Processes 8.1 The Cell Membrane 8.2 Cells and Energy

Investigation 8B Does the color of light affect photosynthesis? Photosynthesis and Color

8.2 What is photosynthesis? 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.

8.2 What is photosynthesis? Chloroplasts are where photosynthesis occurs. Chloroplasts work much like solar cells found in calculators.

8.2 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.

8.2 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.

8.2 Light and color Color is how we experience the energy of light.

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

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

8.2 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.

8.2 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.

8.2 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!

Research Connection So how do stem cells change into other types of cells? Scientists are studying this problem. Amazing Cells

Activity A concept map is a way to represent information visually. Create a concept map to explain how cells get and use energy. Making a Concept Map