1. Energy, Enzymes, and Biological Reactions Ch. 4; 4.1-4.3

2. All You Need is Energy All living things require energy – Move, grow, reproduce, consume, think, react, etc… – Thousands of energy requiring chemical reactions are occurring right now Metabolism  the total amount of materials and energy used by a living thing What factors effect metabolism? – Body size – Amount of activity – Diet – Rate of growth

3. How Do We Measure Energy? Energy itself cannot be measured – We measure energy through its interaction with objects/forces around us Energy  the capacity to do work Forms of energy? – Mechanical – Chemical – Radiant – Electrical

4. Types of Energy What are the two types of energy? – Kinetic and Potential Kinetic  energy in motion – Ball rolling down a hill – Electricity – heat Potential  stored energy – Ball on top of a hill – Chemical bonds How do these terms describe a roller coaster?

5. Systems and Surroundings Thermodynamics  study of energy flow between a system and its surroundings Types of systems: 1)Isolated  no exchange of matter or energy 2)Closed  only exchange energy 3)Open  exchange both matter and energy

6. 1 st Law of Thermodynamics Energy cannot be created or destroyed; it can only be transferred – The total amount of energy in a system/surroundings remains constant Where does the energy we use come from? – The Sun What conversions are needed to get you to read this slide: – At each step energy is lost has heat (K) The movement of heat and the kinetic energy inside organic molecules determine if reactions occur in living things – Reactants have more energy than their products nuclear(P)  radiant(K)  chemical(P)  chemical(K)  mechanical(K)

7. 2 nd Law of Thermodynamics The total disorder (entropy) of a system and its surrounds always increases Living things increase in order as they grow – Cells  Tissue  Organs Do living things violate this law? – No. Taking into account of the surroundings, the waste produced by living things has a higher entropy than the order inside the system

8. Spontaneous Reactions 1 st and 2 nd law determine if a reaction is spontaneous Two trends: 1)Negative enthalpy (-ΔH) – Exothermic; products have less energy than reactants – Endothermic; (+ΔH); reactants have less energy than products 2) Negative entropy (-ΔS) – Products have less order than the reactants Why are a combustion reaction (exothermic) and melting ice (endothermic) both spontaneous?

9. Free Energy determines Spontaneity ΔG= ΔH-TΔS G= energy released H= enthalpy T= temp (Kelvin) S= entropy – If there is a large enough –ΔH or enough disorder, large –ΔS, the ΔG will be negative -ΔG= Release of free energy Combustion reaction: - ΔH is large enough Melting ice: - ΔS is large enough

10. Biology Reactions over Time Chemical reaction can run till completion (run out of reactants) Biological reactions always slow as they research a chemical equilibrium point Forward rate = Reverse rate ΔG=0, the reaction stops; no longer spontaneous Does this occur in a living thing? – No. Living things consume new reactants and use products in other reactions – ΔG=0=death for living things

11. Metabolic Pathways Biological reactions are divided into two groups 1)Exergonic reactions (-ΔG) 2)Endergonic reactions (+ΔG) Mixing of these types create reaction series  metabolic pathways – Catabolic  breakdown molecules to release energy through catabolic reactions – Anabolic  build energy storage molecules through anabolic reactions (biosynthetic reactions) Can you give me an example of both of these pathways?

12. How is this free energy getting around? Adenosine triphosphate (ATP) – 5-C sugar (ribose) – Adenine nitrogenous base – 3 phosphate groups Strong negative charges between P-groups make molecule unstable and releases -7.3 kcal/mol when 3 rd P is removed (hydrolyzed) Where does that energy go? How much is lost as heat?

13. Energy Coupling 3 rd P-group is transferred from ATP to the reactant molecule (phosphorylation) Phosphorylated molecules use the energy to power their reaction Glutamic acid  Glutamine -Adding an ammonia; ΔG= +3.4 kcal/mol; endergonic -First add a P-group from ATP; Glutamic acid + P  Glutamyl phosphate -7.3 kcal/mol + 3.4 kcal/molreaction is -3.9 kcal/mol exergonic

14. ATP of Everyone: ATP/ADP Cycle 50 trillion cells in an adult Millions of molecules, enzymes, pathways, etc.. all using 10 million molecules of ATP every second About 75kg of ATP per day Complex systems living on a demand for energy to replace our ATP How much ATP are you using?

15. Homework Finish reading Ch. 4 Ch. 4 vocab list Go to this site: http://www.freedieting.com/tools/calorie_calculator.htm Calculate your daily Calorie in take. Of this energy only 40% can be used as ATP in the body. How many moles of ATP do you need a day? How many grams of ATP is that? What happened to the other 60%? Show work in your notebook 1 ATP  7300 calories ATP  507 g/mol