7th grade chapter 3 section 3 (energy in cells)


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7th grade chapter 3 section 3 (energy in cells)

  1. 1. Chapter 3: Section 3 Energy in CellsMinersville Area School Distirct Mr. Motuk
  2. 2. I. Trapping Energy for Life A. Cells take chemical energy stored in food and change it into other forms of energy that can be used in metabolism. 1. Metabolism is the total of all chemical activities of an organism that enable it to stay alive, grow, and reproduce. B. Living Things are broken into two groups 1. Consumers are organisms that cannot make their own food. a. Humans, dogs, cats, etc. 2. Producers are organisms that can make their own food. a. Plants
  3. 3. II. Photosynthesis A. Photosynthesis-the process of changing light energy into chemical energy. 1. Producers take energy from the sunlight and use it to make sugar from carbon dioxide. B. Steps of photosynthesis 1. Energy from Sun is absorbed by the chlorophyll in plant cells. 2. In the chloroplasts, the Sun’s energy is used to split water into oxygen and hydrogen. a. The light energy is then used to combine these hydrogen atoms with carbon dioxide to form a sugar.
  4. 4. B. Steps of Photosynthesis (cont’d) 3. Photosynthesis takes place inside chlorplasts. 4. Photosynthesis equation a. 6CO2 + 6H2O + Light Energy C6H1206 + 6O2C. Products of Photosynthesis 1. Producers use some of the sugars (C6H1206) they make for energy. The rest is stored as carbohydrates or lipids. 2. Consumers eat Producers in order to obtain this energy. a. Consumers can also eat other consumers to obtain energy.
  5. 5. Chapter 3: Section 3III. Releasing Energy for Life A. Cellular Respiration: Both producers and consumers break down food molecules in a process called cellular respiration. 1. In most animals glucose is the food that is broken down. 2. This process takes place within the mitochondria and uses that oxygen that you take in as you breathe. 3. Respiration Equation a. C6H1206 + 6O2 6CO2 + 6H2O + energy
  6. 6. III. Releasing Energy for Life B. What happens during respiration? 1. Food molecules are broken down to release stored energy. 2. Respiration of carbohydrates begins in the cytoplasm. a. Carbohydrates are broken down into glucose molecules. (C6H1206) b. Each glucose molecule is broken down into simpler molecules, releasing energy.
  7. 7. Chapter 3: Section 3 (Energy For Life) B. What Happens During Respiration (cont’d) 3. Respiration moves into the mitochondria a. The two simpler molecules are broken down again, releasing much more energy. b. This process uses oxygen and produces CO2 and water as wastes.
  8. 8. Chapter 3: Section 3 (Energy For Life) C. Fermentation 1. Fermentation is a form of respiration that converts energy from glucose when oxygen is insufficient. a. Lesser amounts of energy are produced by fermentation. i. Lactic Acid is formed during this process. ii. Lactic Acid causes the muscles to burn and be sore and stiff. b. Some yeasts and bacteria use alcohol fermentation to release energy and carbon dioxide.
  9. 9. Chapter 3: Section 3 (Energy For Life) D. Comparing Photosynthesis and Respiration 1. Both involve complex sets of reactions. 2. Both occur in specific organelles, involve energy, and require enzymes. 3. The end products of photosynthesis are the starting blocks for respiration. a. In many ways photosynthesis is the opposite of respiration.