Thermodynamics and ATP

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

(a) First law of thermodynamics (b) Second law of thermodynamics Figure 8.3 Heat Chemical energy Figure 8.3 The two laws of thermodynamics. (a) First law of thermodynamics (b) Second law of thermodynamics

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

WHAT IS THE ΔG IN THESE EVENTS? Figure 8.5b WHAT IS THE ΔG IN THESE EVENTS? Figure 8.5 The relationship of free energy to stability, work capacity, and spontaneous change. (a) Gravitational motion (b) Diffusion (c) Chemical reaction

Amount of energy released (G  0) Figure 8.6a (a) Exergonic reaction: energy released, spontaneous Reactants Amount of energy released (G  0) Energy Free energy Products Figure 8.6 Free energy changes (G) in exergonic and endergonic reactions. Progress of the reaction

Amount of energy required (G  0) Figure 8.6b (b) Endergonic reaction: energy required, nonspontaneous Products Amount of energy required (G  0) Energy Free energy Reactants Figure 8.6 Free energy changes (G) in exergonic and endergonic reactions. Progress of the reaction

(a) The structure of ATP Figure 8.8a Adenine Phosphate groups Ribose Figure 8.8 The structure and hydrolysis of adenosine triphosphate (ATP). (a) The structure of ATP

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

Phosphorylated intermediate Figure 8.9 Glutamic acid conversion to glutamine (a) NH3 NH2 GGlu = +3.4 kcal/mol Glu Glu Glutamic acid Ammonia Glutamine (b) Conversion reaction coupled with ATP hydrolysis NH3 1 P 2 ADP NH2 ADP ATP P i Glu Glu Glu Glutamic acid Phosphorylated intermediate Glutamine GGlu = +3.4 kcal/mol (c) Free-energy change for coupled reaction Figure 8.9 How ATP drives chemical work: Energy coupling using ATP hydrolysis. NH3 NH2 ATP ADP P i Glu Glu GGlu = +3.4 kcal/mol GATP = 7.3 kcal/mol + GATP = 7.3 kcal/mol Net G = 3.9 kcal/mol

Protein and vesicle moved Figure 8.10 Transport protein Solute ATP ADP P i P P i Solute transported (a) Transport work: ATP phosphorylates transport proteins. Vesicle Cytoskeletal track Figure 8.10 How ATP drives transport and mechanical work. ATP ADP P i ATP Motor protein Protein and vesicle moved (b) Mechanical work: ATP binds noncovalently to motor proteins and then is hydrolyzed.

Energy from catabolism (exergonic, energy-releasing processes) Figure 8.11 ATP H2O Energy from catabolism (exergonic, energy-releasing processes) Energy for cellular work (endergonic, energy-consuming processes) Figure 8.11 The ATP cycle. ADP P i

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?

ATP Synthase permeable to H+ H+ flow down concentration gradient catalytic head rod rotor 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 Pi to ADP: ADP + Pi  ATP ADP P + ATP But… How is the proton (H+) gradient formed?