Thermodynamics and ATP

Figure 8.UN01 Enzyme 1 Enzyme 2 Enzyme 3 Reaction 1 Reaction 2Reaction 3 ProductStarting molecule A B C D

Figure 8.3 (a) First law of thermodynamics (b) Second law of thermodynamics Chemical energy Heat

Gibbs Free Energy  ΔG = ΔH – TΔS  ΔH is change in enthalpy or total energy  ΔS is change in entropy  In a spontaneous process the ΔG is always negative.  System must either give up enthalpy OR  Have a positive TΔS  If ΔG is positive or Zero the process is NOT SPONTANEOUS videos/2011/9/14/gibbs-free-energy.html

Figure 8.5b (a) Gravitational motion (b) Diffusion(c) Chemical reaction WHAT IS THE ΔG IN THESE EVENTS?

Figure 8.6a (a) Exergonic reaction: energy released, spontaneous Reactants Energy Products Progress of the reaction Amount of energy released (  G  0) Free energy

Figure 8.6b (b) Endergonic reaction: energy required, nonspontaneous Reactants Energy Products Amount of energy required (  G  0) Progress of the reaction Free energy

Figure 8.8a (a) The structure of ATP Phosphate groups Adenine Ribose

Figure 8.8b Adenosine triphosphate (ATP) Energy Inorganic phosphate Adenosine diphosphate (ADP) (b) The hydrolysis of ATP

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 8.11 Energy from catabolism (exergonic, energy-releasing processes) Energy for cellular work (endergonic, energy-consuming processes) ATP ADPP i H2OH2O

How is ATP Made in a Cell? Substrate Level Phosphorylation

Chemiosmosis Start with a mitochondrion or chloroplast Trap H + in the intermembrane space

Chemiosmosis Start with a mitochondrion or chloroplast Trap H + in the intermembrane space How can this lead to ATP production?

H+H+ catalytic head rod rotor H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ATP But… How is the proton (H + ) gradient formed? ADP P +  Enzyme channel in mitochondrial membrane  permeable to H +  H + flow down concentration gradient  flow like water over water wheel  flowing H+ cause change in shape of ATP synthase enzyme  powers bonding of P i to ADP: ADP + P i  ATP ATP Synthase