Presentation on theme: "LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert."— Presentation transcript:
Figure 8.2 A diver has more potential energy on the platform than in the water. Diving converts potential energy to kinetic energy. Climbing up converts the kinetic energy of muscle movement to potential energy. A diver has less potential energy in the water than on the platform.
Figure 8.5 More free energy (higher G) Less stable Greater work capacity In a spontaneous change The free energy of the system decreases ( G 0) The system becomes more stable The released free energy can be harnessed to do work Less free energy (lower G) More stable Less work capacity (a) Gravitational motion (b) Diffusion(c) Chemical reaction
Figure 8.6 (a) Exergonic reaction: energy released, spontaneous (b) Endergonic reaction: energy required, nonspontaneous Reactants Energy Products Progress of the reaction Amount of energy released ( G 0) Reactants Energy Products Amount of energy required ( G 0) Progress of the reaction Free energy
Figure 8.9 Glutamic acid Ammonia Glutamine (b) Conversion reaction coupled with ATP hydrolysis Glutamic acid conversion to glutamine (a) (c) Free-energy change for coupled reaction Glutamic acid Glutamine Phosphorylated intermediate Glu NH 3 NH 2 Glu G Glu = +3.4 kcal/mol ATP ADP NH 3 Glu P P i ADP Glu NH 2 G Glu = +3.4 kcal/mol Glu NH 3 NH 2 ATP G ATP = 7.3 kcal/mol G Glu = +3.4 kcal/mol + G ATP = 7.3 kcal/mol Net G = 3.9 kcal/mol 1 2
Figure 8.10 Transport protein Solute ATP P P i ADP P i ADP ATP Solute transported Vesicle Cytoskeletal track Motor proteinProtein and vesicle moved (b) Mechanical work: ATP binds noncovalently to motor proteins and then is hydrolyzed. (a) Transport work: ATP phosphorylates transport proteins.
Figure 8.13 Course of reaction without enzyme E A without enzyme E A with enzyme is lower Course of reaction with enzyme Reactants Products G is unaffected by enzyme Progress of the reaction Free energy
Figure Substrates Substrates enter active site. Enzyme-substrate complex Enzyme Products Substrates are held in active site by weak interactions. Active site can lower E A and speed up a reaction. Active site is available for two new substrate molecules. Products are released. Substrates are converted to products
Figure 8.16 Optimal temperature for typical human enzyme (37°C) Optimal temperature for enzyme of thermophilic (heat-tolerant) bacteria (77°C) Temperature (°C) (a) Optimal temperature for two enzymes Rate of reaction pH (b) Optimal pH for two enzymes Optimal pH for pepsin (stomach enzyme) Optimal pH for trypsin (intestinal enzyme)
Figure 8.19 Regulatory site (one of four) (a) Allosteric activators and inhibitors Allosteric enzyme with four subunits Active site (one of four) Active form Activator Stabilized active form Oscillation Non- functional active site Inactive form Inhibitor Stabilized inactive form Inactive form Substrate Stabilized active form (b) Cooperativity: another type of allosteric activation
Figure 8.21 Active site available Isoleucine used up by cell Feedback inhibition Active site of enzyme 1 is no longer able to catalyze the conversion of threonine to intermediate A; pathway is switched off. Isoleucine binds to allosteric site. Initial substrate (threonine) Threonine in active site Enzyme 1 (threonine deaminase) Intermediate A Intermediate B Intermediate C Intermediate D Enzyme 2 Enzyme 3 Enzyme 4 Enzyme 5 End product (isoleucine)
Figure 8.22 Mitochondria The matrix contains enzymes in solution that are involved in one stage of cellular respiration. Enzymes for another stage of cellular respiration are embedded in the inner membrane. 1 m