3. Cellular Respiration vs. Photosynthesis Organelles Mitochondria Eukaryotic cells Structure is key Two membranes Space between membranes Matrix makes up inner membrane Lots of enzymes found here for chemical reactions Complex folding=many sites for reactions to take place Maximizes ATP production Chloroplast More about this one later…
4. Energy Heat (thermal) Light (solar) Electrical What carries energy? Electrons (little energy packets) Negatively charged particle Involved in making bonds between atoms Electromagnetic spectrum
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6. How is Energy Transferred? Think food chain! First Law of Thermodynamics aka the Law of Conservation of Energy E cannot be created or destroyed, only transferred (converted)
7. Kinetic vs. Potential Energy of motion Anything moving or in motion Ex. Climbing stairs Leg muscles working Stored energy due to an objects position or arrangement As you climb up, you are getting higher, more gravitational pull, increase potential E
8. Two Types of Kinetic Energy Directed kinetic energy Ex. Your body as it moves down slide Random kinetic energy of molecular motion Thermal energy Ex. When your body collides with water. Air and water molecules are forced to move and collide at random, transferring energy
9. Thermal Energy Created from Random molecular motion “Heat” is thermal energy that is transferred from warmer object to cooler object
10. So exactly what happens as you go down the slide? As you climb up the slideKinetic E When you reach top of slidepotential E As you slide downdirected kinetic E When you hit water and stopRandom kinetic E of molecular motion
11. You cannot retrieve thermal energy, so you must get new source of energy to climb back up the slide What do you do?
12. Eat food! Food is composed of organic compounds Carbohydrates Fats Proteins All rich in E These organic compounds contain a form of potential energy we call CHEMICAL ENERGY
13. Organic compounds Potential to do work is in the arrangement of atoms in the molecules Amount of potential energy depends on the structure of the molecules When you break a bond, you release E Energy now available for muscles to do work Structures of… Proteins Carbohydrates Fats
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15. Cells and Cars use Combustion Cells Glucose Oxygen Energy to do work Transport, mechanical, chemical Releases carbon dioxide and water Cars Hydrocarbons (in gasoline) Oxygen Energy to do mechanical work Releases carbon dioxide and water
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17. calorie Amount of energy required to raise the temperature of 1 g of water 1*C Very tiny Not practical to measure energy in food Express in kilocalories (kcal), or Calories, what is on the nutrition label KHDmdcm
18. Burning food… Changes chemical energy to thermal energy (releases heat) Measure increase of water temperature and definition of calorie to find out how much chemical energy is in food
19. Practice problem If a peanut is burned and the temperature of 1 kilogram of water is raised by 8*C, how many calories are in the peanut? How many Calories (kcal)? How many calories?
20. Find the amount of calories in each food and which provides the most energy1 2 3
