Biology 105 Chapter 7: Energy and Metabolism Pgs Chapter 7: Energy and Metabolism Pgs

Student Outcomes / Define Energy and how it is related to work and heat / Contrast potential, kinetic energy and the laws of thermodynamics / Distinguish between exergonic and endergonic reactions / Define Energy and how it is related to work and heat / Contrast potential, kinetic energy and the laws of thermodynamics / Distinguish between exergonic and endergonic reactions

Student Outcomes / Discuss entropy and enthalpy and how free energy affects both processes. / Discuss the role of ATP in energy metabolism of the cell. / Explain how enzymes are regulated and their functions in reactions. / Discuss entropy and enthalpy and how free energy affects both processes. / Discuss the role of ATP in energy metabolism of the cell. / Explain how enzymes are regulated and their functions in reactions.

Energy Energy - the capacity to do work Measured in Kilojoules (Kj) or Kilocalories, kcal Energy - the capacity to do work Measured in Kilojoules (Kj) or Kilocalories, kcal

Terms of Energy Potential Energy - capacity to do work Kinetic Energy - Energy of motion Chemical Energy - Potential energy stored in chemical bonds Mechanical Energy - Performing work by moving matter (muscles) Potential Energy - capacity to do work Kinetic Energy - Energy of motion Chemical Energy - Potential energy stored in chemical bonds Mechanical Energy - Performing work by moving matter (muscles)

Thermodynamics / The study of energy / Closed system - no energy exchange with its surroundings / Open system - energy exchange with surroundings / The study of energy / Closed system - no energy exchange with its surroundings / Open system - energy exchange with surroundings

Laws of thermodynamics / 1st Law / Energy is neither created nor destroyed, it just changes form / Organisms cannot create their own energy to do work, they must capture energy from the environment and transform it to a useable form / 1st Law / Energy is neither created nor destroyed, it just changes form / Organisms cannot create their own energy to do work, they must capture energy from the environment and transform it to a useable form

Laws of Thermodynamics 2nd law As energy is converted from one form to another, some energy is lost as HEAT to the surroundings. Measured as Entropy 2nd law As energy is converted from one form to another, some energy is lost as HEAT to the surroundings. Measured as Entropy

Metabolism / All the chemical reactions in a cell / Two Types / Anabolism - complex molecules are synthesized from simpler substances, Ex: organic compounds / Catabolism - complex molecules are broken down into smaller substances. / All the chemical reactions in a cell / Two Types / Anabolism - complex molecules are synthesized from simpler substances, Ex: organic compounds / Catabolism - complex molecules are broken down into smaller substances.

Energy to do work / H=G+TS / H=Enthalpy (potential energy) / G=Free energy / T=Temperature (absolute-Kelvin) / S=Entropy (unuseable energy) / ∆G = change in free energy / H=G+TS / H=Enthalpy (potential energy) / G=Free energy / T=Temperature (absolute-Kelvin) / S=Entropy (unuseable energy) / ∆G = change in free energy

Exergonic Reactions / Release energy-less free energy in the products than in the reactants, downhill slope on a graph. / ∆G= a negative number / Usually spontaneous and catabolic / Release energy-less free energy in the products than in the reactants, downhill slope on a graph. / ∆G= a negative number / Usually spontaneous and catabolic

Endergonic reaction / Gain in free energy - More energy in the products than in the reactants. ∆G = a positive value / For every Endergonic reaction - driven by an exergonic reaction / Anabolic reactions / Gain in free energy - More energy in the products than in the reactants. ∆G = a positive value / For every Endergonic reaction - driven by an exergonic reaction / Anabolic reactions

ATP / Adenosine Triphosphate - Chemical compound of energy in all living things. / ATP has three parts: adenine (nitrogenous base), ribose (5 carbon sugar) and three phosphates / Adenosine Triphosphate - Chemical compound of energy in all living things. / ATP has three parts: adenine (nitrogenous base), ribose (5 carbon sugar) and three phosphates

ATP A cell continually spends its ATP and it must be continually replaced. The energy is stored in the phosphate bonds ∆G (free energy) is app. -32 kJ/mol or -7.6 kcal/mol (Energy released by the phosphate bond breaking) A cell continually spends its ATP and it must be continually replaced. The energy is stored in the phosphate bonds ∆G (free energy) is app. -32 kJ/mol or -7.6 kcal/mol (Energy released by the phosphate bond breaking)

ATP synthesis / ATP - ADP - AMP / 10 times the amount of ATP vs ADP in a typical cell. / ATP - ADP - AMP / 10 times the amount of ATP vs ADP in a typical cell.

ATP Fun Facts / Estimated 10 million molecules of ATP are made from ADP every second in every cell / Adult human at rest uses about 45 kg of ATP each day / ATP present in the body is less than 1g / Estimated 10 million molecules of ATP are made from ADP every second in every cell / Adult human at rest uses about 45 kg of ATP each day / ATP present in the body is less than 1g

Redox Reactions / Oxidation - chemical process where a substance loses electrons / Reduction - a substance gains electrons. / When a substance is oxidized it gives up energy and the opposite is true / NAD+ becomes NADH / Oxidation - chemical process where a substance loses electrons / Reduction - a substance gains electrons. / When a substance is oxidized it gives up energy and the opposite is true / NAD+ becomes NADH

Enzymes / Biological catalysts - increase the speed of a chemical reaction without being consumed by the reaction. / Most are proteins / Very specific to their job. Have a specific pH and temperature they function at. Will denature if too strong of pH or too high temperature. / Biological catalysts - increase the speed of a chemical reaction without being consumed by the reaction. / Most are proteins / Very specific to their job. Have a specific pH and temperature they function at. Will denature if too strong of pH or too high temperature.

Enzymes / Example Hydrogen Peroxide H 2 O 2 is a poisonous substance to cells. It breaks down slowly / One molecule of the enzyme Catalase will decompose 40 million molecules of hydrogen peroxide per second. / Example Hydrogen Peroxide H 2 O 2 is a poisonous substance to cells. It breaks down slowly / One molecule of the enzyme Catalase will decompose 40 million molecules of hydrogen peroxide per second.

Activation Energy / Energy needed for a reaction to occur / Needed to break the existing bonds and begin the reaction. / Enzymes lower the Activation Energy needed / Energy needed for a reaction to occur / Needed to break the existing bonds and begin the reaction. / Enzymes lower the Activation Energy needed

Substrates / Enzymes form a ‘complex’ with the substrate at an ‘active site’ (connect at a groove that matches enzyme to substrate)

Enzyme examples / Sucrase / Pepsin / Trypsin / Catalase / Sucrase / Pepsin / Trypsin / Catalase

Enzyme Regulation / Cells regulate enzymes / Feedback inhibition / A-----B-----C-----D / As the concentration of Product D increases, it inhibits (stops) the Enzyme that acts on Reactant A. / Cells regulate enzymes / Feedback inhibition / A-----B-----C-----D / As the concentration of Product D increases, it inhibits (stops) the Enzyme that acts on Reactant A.

Reversible inhibition / Competitive inhibition / The inhibitor competes with the substrate for binding to the active site of the enzyme / Noncompetitive inhibition / The inhibitor competes with the substrate for binding at the non active site. / Competitive inhibition / The inhibitor competes with the substrate for binding to the active site of the enzyme / Noncompetitive inhibition / The inhibitor competes with the substrate for binding at the non active site.

Irreversible inhibition / An inhibitor permanently inactivates or destroys the enzyme / EX: cyanide affects cytochrome oxidase / Sulfa drugs - prevent microorganisms from synthesizing folic acid. / Penicillin inhibit the enzyme transpeptidase needed for cell wall construction. / An inhibitor permanently inactivates or destroys the enzyme / EX: cyanide affects cytochrome oxidase / Sulfa drugs - prevent microorganisms from synthesizing folic acid. / Penicillin inhibit the enzyme transpeptidase needed for cell wall construction.