Membranes & Diffusion ( last outline) Thurs 9 / 10 /13

1. Membranes & Diffusion (last outline) Thurs 9/10/13 • membranes • diffusion & facilitated diffusion • osmosis, active transport, endocytosis & exocytosis • Basic energy concepts • conservation, chemical energy, activation energy • enzymes • ATP - energy molecule • Redox reactions

2. Energy: Potential & Kinetic Energy • A handful of peanuts contains enough energy to boil a quart of water • It takes about 10 million ATP molecules per second to power an active muscle cell

3. About 75% of the energy generated by a car’s engine is lost as heat • You’d have to run about 14 miles to burn the calories from a pepperoni pizza

4. Thermodynamics: • 1st Law of Thermodynamics: • the law of • total amount of • energy can not be • energy is

5. 2nd Law of Thermodynamics: • The second law of thermodynamics states that energy cannot • Efficiency of • some energy escapes in the form of pg 100

6. Conservation of Energy Energy is defined as the capacity to perform work • Kinetic energy is the • Potential energy is

7. Waste products poor in chemical energy Fuel rich in chemical energy Heat energy Gasoline Combustion Kinetic energy of movement Oxygen Water (a) Energy conversion in a car Chemical Energy • Is a form of • Is found in • What drives our cellular metabolism

8. Energy Transformations: • Energy is stored (endergonic) • require an • driven by • ex: cellular respiration (energy from break down of food is stored in ATP) • Energy is released (exergonic) • ex: splitting ATP to release energy fig 6.3

9. Energy of Activation: • energy needed • energy needed to • biological reactions happen fig 6.5

10. Enzymes • biological catalysts • speed up

11. How Enzymes Work: • proteins or nucleic acids • enzymes LOWERS • enzyme shape fig 6.6

12. How Enzymes Work: • specificity • e.g., sucrase breaks down sucrose! • used over and over • optimal conditions • e.g., see figures 6.8 & 6.9

13. Biochemical Pathways: • series of chemical reactions where the product of one reaction • frequently embedded in a membrane where the enzyme assembly

14. Regulation of enzymatic activity: • enzyme activity may be repressed by the presence of a repressor molecule which • enzyme activity may be “activated” by the binding of an activator;

15. Enzyme Inhibitors • Competitive inhibitor • Noncompetitive inhibitor

16. Feedback Inhibition: • Chemical pathway with a series of enzymes that allows • End product • 1st reactant fig 6.10

17. ATP - adenosine triphosphate • ENERGY STORAGE MOLECULE! • ADP + Pi + energy  ATP • when bonds break -- • when bonds formed -- • ATP molecules Coupled reaction

18. Examples of work: • cellular work = metabolism “Cellular Work” active transport muscle contraction

19. Oxidative-Reduction • oxidation • oxygen has a • oxidation is the process of • an oxidized molecule • reduction • reduced atoms or • may gain more than just • energy is

20. Cycle of Energy: Cellular Respiration & Photosynthesis fig 6.11 • photosynthesis: • cellular respiration: