METABOLISM…..what is yours?

1. METABOLISM…..what is yours? Calculate Basal Metabolic Rate (calories burned to stay alive each day) Adult Women:65.5 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years) Adult Men:66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age in years) Choose an active modifier 1.25 if you are lightly active. 1.40 if you exercise almost every day. 1.60 if you are a full time construction worker, or professional athlete. (BMR) x (Activity Modifier) = Active Metabolic Rate IF you WANT TO LOOSE WEIGHT, what do you HAVE to do?

2. Metabolism, energy, and life • METABOLISM…..total chemical reactions in an organism. • Anabolic pathway…..synthesizing complex molecules. • Ex: Synthesis of proteins • Catabolic pathway….release energy by breaking complex molecules down. • Ex: cellular respiration

4. ENERGY • Energy…capacity to do work. • Potential (stored) • Kinetic (moving) • Thermodynamics…..energy transformations study. • 1ST LAW….energy can’t be created or destroyed. • 2ND LAW….every energy transformation INCREASES the entrOPY of the universe. ENTROPY…a quantitative measure of DISORDER or randomness. ENTHALPY…a measure of energy ASSOCIATED with a system. • WHAT IS MEANT BY THIS SENTENCE? • By combining the first and second laws of thermodynamics, we can conclude that the QUANTITY of energy in the universe is constant, but its QUALITY is not.

5. Free Energy and Metabolism • Free Energy-the portion of a system’s energy that can perform work • Exergonic reactions-a net release of energy. • Endergonic reactions-absorbs free energy from the environment

6. ATP • Immediate source of cellular energy • Common to ALL living things • Made by each cell • 107 molecules used and regenerated/second/cell

7. Cells do not have enough energy! • Solved by use of enzymes

9. Environmental EFFECTS • pH and temperature-optimum for best results • Denature (high & low temp; 37 = optimum temp) • Cofactors • Bound tightly to active site • Bound loosely or reversely to substrate • If organic called coenzyme • Inhibitors • can be competitive (block substrates) • noncompetitive (doesn’t block enzyme but changes shape)

10. Regulation • Problem-enzymes work too well • Allosteric regulation • Allosteric site is a receptor site on part of an enzyme separate from the active site. • Feedback inhibition • There is a second binding site on the enzyme where the inhibitor binds, & inhibitor is not necessarily similar in structure to the substrate. • The absence or presence of the inhibitor at this second binding site activates or deactivates the enzyme. • The inhibitor is usually the product of a reaction farther on down the metabolic pathway.

11. Comparing FEEDBACK & INHIBITION • In competitive inhibition the inhibitor is similar in structure to the substrate and binds to the enzyme at the active site, preventing the substrate from binding. • In feedback inhibition, the inhibitor binds to the enzyme at a site away from the active site and acts by altering the shape of the enzyme in such a way that it is incapable of catalyzing the reaction. • Feedback inhibition is a natural part of the process by which an organism regulates the chemical reactions that take place in its cells. In that sense it is done on purpose. • Competitive inhibition usually involves inhibitors, commonly called poisons, that do not belong in the cell.  

12. Evolution of Energy converting processes • Substrate-levelphosphorylation: direct transfer of a phosphate from “food” to ADP • Chemiosmosis: establishment of a proton gradient and subsequent conversion of Proton Motive Force into ATP