1. Ground Rules of Metabolism

2.  Catalase is an enzyme that helps the body break down toxic substances in alcoholic drinks

3.  The liver plays a central role in alcohol metabolism  Consumption of too much alcohol, as in binge drinking, can lead to alcoholic hepatitis or alcoholic cirrhosis

4.  Capacity to do work  Forms of energy  Potential energy  Kinetic energy  Chemical energy

5.  The total amount of energy in the universe remains constant  Energy can undergo conversions from one form to another, but it cannot be created or destroyed

6. ENERGY LOST With each conversion, there is a one-way flow of a bit of energy back to the environment. Nutrients cycle between producers and consumers. ENERGY GAINED Sunlight energy reaches environments on Earth. Producers of nearly all ecosystems secure some and convert it to stored forms of energy. They and all other organisms convert stored energy to forms that can drive cellular work. ENERGY LOST Energy continually flows from the sun. producers consumers NUTRIENT CYCLING Fig. 6-4, p.74

7.  No energy conversion is ever 100 percent efficient  The total amount of energy is flowing from high-energy forms to forms lower in energy

8. http://www.youtube.com/watch?v=DPjMPeU5 OeM http://www.youtube.com/watch?v=JBmykor- 2kU

9.  Measure of degree of disorder in a system  The world of life can resist the flow toward maximum entropy only because it is resupplied with energy from the sun

10.  Energy carriers  Enzymes  Cofactors  Transport proteins  Reactants  Intermediates  Products

11.  Cells “earn” ATP in exergonic reactions  Cells “spend” ATP in endergonic reactions base sugar three phosphate groups Fig. 6-6a, p.96

12.  Energy input required  Product has more energy than starting substances glucose, a high energy product ENERGY IN low energy starting substances 6 + 6O 2 6 66

13.  Energy is released  Products have less energy than starting substance glucose, a high energy starting substance + 6O 2 66 low energy products ENERGY OUT

14. reactions that release energy reactions that require energy cellular work (e.g., synthesis, breakdown, or rearrangement of substances; contraction of muscle cells; active transport across a cell membrane) ATP ADP + P i ATP Fig. 6-7a, p.75 ATP/ADP Cycle

15.  Enzymes are catalytic molecules  They speed the rate at which reactions approach equilibrium

16. 1) Enzymes do not make anything happen that could not happen on its own. They just make it happen much faster. 2) Reactions do not alter or use up enzyme molecules.

17. 3) The same enzyme usually works for both the forward and reverse reactions. 4) Each type of enzyme recognizes and binds to only certain substrates.

18. http://www.youtube.com/watch?v=ok9esggzN 18

19.  For a reaction to occur, an energy barrier must be surmounted  Enzymes make the energy barrier smaller activation energy without enzyme activation energy with enzyme energy released by the reaction products starting substance

20. Fig. 6-10b, p.97 Hydrogen peroxide (H 2 O 2 ) enters a catalase. It is the substrate for a reaction aided by an iron molecule in a heme group (red). A hydrogen of the peroxide is attracted to histidine, an amino acid projecting into the cavity. One oxygen binds the iron. This binding destabilizes the peroxide bond which breaks. Water (H 2 O) forms. In a later reaction, another H 2 O 2 will pull the oxygen from iron, which will then be free to act again. How Catalase Works

21.  Substrate molecules are brought together  Substrates are oriented in ways that favor reaction  Active sites may promote acid-base reactions  Active sites may shut out water

22.  Competitive—competes with the substrate for the ACTIVE SITE  Noncompetitive (AKA allosteric)—inhibitor bonds to allosteric site (away from active site)

23. allosteric inhibitor allosteric binding site vacant; active site can bind substrate active site altered, can’t bind substrate

24. allosteric activator vacant allosteric binding site active site altered, can bind substrate active site cannot bind substrate enzyme active site

25.  When a substrate binds to the active site of one of the enzyme’s subunits causing the same effect on all of the enzyme’s subunits  This can “prime” an enzyme to start accepting more and more substrate

26. enzyme 2enzyme 3enzyme 4 enzyme 5 enzyme 1 SUBSTRATE END PRODUCT (tryptophan) A cellular change, caused by a specific activity, shuts down the activity that brought it about

27.  Positive---Ex: contractions & childbirth  Negative—AKA antagonistic Ex: fever

28. Temperature pH Salt concentration Allosteric regulators Coenzymes and cofactors

29.  Small increase in temperature increases molecular collisions, reaction rates  High temperatures disrupt bonds and destroy the shape of active site

30. Fig. 6-13, p.81 Effect of Temperature

31. Fig. 6-14a, p.81

32.  Cofactors  Coenzymes NAD +, NADP +, FAD Accept electrons and hydrogen ions; transfer them within cell Derived from vitamins  Metal ions Ferrous iron in cytochromes

33.  Defined as enzyme- mediated sequences of reactions in cells  Biosynthetic (anabolic) – ex: photosynthesis  Degradative (catabolic) – ex: aerobic respiration

34.  Cells release energy efficiently by electron transfers, or oxidation-reduction reactions (“redox” reactions)  One molecule gives up electrons (is oxidized) and another gains them (is reduced)  Hydrogen atoms are commonly released at the same time, thus becoming H +

35.  Arrangement of enzymes, coenzymes, at cell membrane  As one molecule is oxidized, next is reduced  Function in aerobic respiration and photosynthesis

36.  An outcome of enzyme-mediated reactions that release energy as fluorescent light

37. Fig. 6-19, p.103 Bioluminescent Bacteria

39. http://www.youtube.com/watch?v=NzxgpsW_r JI