1. Conservation of Energy Energy is defined as the capacity to cause change. Kinetic energy is the energy of motion. Potential energy is stored energy. It is energy that an object has because of its –location or –structure.

2. Figure 5.1 Climbing converts kinetic energy to potential energy. Greatest potential energy Diving converts potential energy to kinetic energy. Least potential energy

3. Conservation of Energy –Energy cannot be created or destroyed. –Energy can be converted from one form to another. Conservation of Energy © 2013 Pearson Education, Inc.

4. Entropy Every energy conversion releases some energy in the form of heat. Energy conversions, therefore, are not 100% efficient. This inefficiency increases the “entropy,” or “disorder” of the universe. © 2013 Pearson Education, Inc.

5. Chemical Energy Molecules store potential energy in the covalent bonds between their atoms. Organic (carbon-containing) compounds are relatively rich in such chemical energy. © 2013 Pearson Education, Inc.

6. Chemical Energy Chemical energy can be released in a chemical reaction, often by breaking covalent bonds. Living cells and automobile engines use the same basic process to make chemical energy do work. © 2013 Pearson Education, Inc.

7. Figure 5.2 Fuel rich in chemical energy Energy conversion Waste products poor in chemical energy Oxygen Carbon dioxide Energy conversion in a car Energy for cellular work Energy conversion in a cell Heat energy Heat energy Carbon dioxide Oxygen Combustion Cellular respiration Kinetic energy of movement ATP Octane (from gasoline) Glucose (from food) Water

8. Cellular respiration is –the process of breaking bonds in glucose and other nutrient molecules in order to… –Convert the energy stored in those bonds to a form the cell can use to perform work (ATP). Chemical Energy © 2013 Pearson Education, Inc.

9. Humans convert about 34% of the energy in food to useful work, such as the contraction of muscles. About 66% of the energy released by the breakdown of fuel molecules generates body heat. Chemical Energy © 2013 Pearson Education, Inc.

10. Food Calories A calorie is the amount of energy that can raise the temperature of one gram of water by 1 degree Celsius. Food Calories are kilocalories, equal to 1,000 calories. The energy of calories in food is utilized to fuel many daily activities. © 2013 Pearson Education, Inc.

11. ATP AND CELLULAR WORK Chemical energy is –released by the breakdown of organic molecules during cellular respiration and –used to generate molecules of ATP. ATP –acts like an energy shuttle, –stores energy obtained from food, and –releases it later as needed. © 2013 Pearson Education, Inc.

12. The Structure of ATP ATP (adenosine triphosphate) –Consists of: –Adenine (a nitrogenous base) –Ribose sugar –3 Phosphate Groups –When ATP is broken down to ADP and a phosphate group (P), energy is released. © 2013 Pearson Education, Inc.

13. Figure 5.4 Triphosphate Diphosphate Adenosine Energy ATPADP P PP P P P Phosphate (transferred to another molecule)

14. ATP ADP P P (a) Motor protein performing mechanical work (moving a muscle fiber) Protein moved Motor protein The energy obtained by breaking down ATP helps cells perform mechanical work.

15. ATP ADP P P P (b) Transport protein performing transport work (importing a solute) Solute Solute transported Transport protein The energy obtained by breaking down ATP helps cells perform transport work.

16. Figure 5.5c ATP ADP P P P X XY Y (c) Chemical reactants performing chemical work (promoting a chemical reaction) Product made Reactants The energy obtained by breaking down ATP helps cells perform chemical work.

17. The ATP Cycle Each cell in our body requires 1 x 10 6 ATP molecules per second! © 2013 Pearson Education, Inc. Cellular respiration: chemical energy harvested from fuel molecules Energy for cellular work ATP ADP P

18. ENZYMES Metabolism is the total of all chemical reactions in an organism. Most metabolic reactions require the assistance of enzymes, which proteins that speed up chemical reactions. © 2013 Pearson Education, Inc.

19. Figure 5.8c Ribbon model showing the polypeptide chains of the enzyme lactase

20. Figure 5.7a (a) Without enzyme Reactant Products Activation energy barrier Energy

21. Figure 5.7b (b) With enzyme Reactant Products Activation energy barrier reduced by enzyme Enzyme Energy

22. Figure 5.7 (a) Without enzyme (b) With enzyme Reactant Products Activation energy barrier Activation energy barrier reduced by enzyme Enzyme Energy

23. Figure 5.9-1 Active site Enzyme (sucrase) Ready for substrate 1

24. Figure 5.9-2 Active site Enzyme (sucrase) Ready for substrate Substrate (sucrose) Substrate binding 1 2

25. Figure 5.9-3 Active site Enzyme (sucrase) Ready for substrate Substrate (sucrose) Substrate binding Catalysis H2OH2O 1 2 3

26. Figure 5.9-4 Active site Enzyme (sucrase) Ready for substrate Substrate (sucrose) Substrate binding Catalysis H2OH2O Fructose Glucose Product released 4 1 2 3