lect 12 - Microbial Energetics Learning goals Learn about...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Microbial Energetics Learning goals Learn about biomolecules used by microbes to generate energy Learn about electron potential of molecules Understand the biophysical nature that allows electron flow to push protons across a membrane Learn how a proton gradient is converted into ATP by the action of ATPase Overview Microbial diversity = metabolic diversity Atrazine degradation Fe/Mn oxidation W. C. Ghiorsee Ann. Rev. Microbiol. 1984.38:515-50 Fe 2+ (dissolved iron in water) + H + + 1/4O 2 Fe 3+ + 1/2H 2 O Fe3+ + 3H2O i Fe(OH)3 (insoluble precipitant) +3H+ http://www.umaine.edu/WaterResearch/FieldGuide/inthewater.h Leptothrix discophora Methanogenic CO 2 + 4H 2 CH 4 + i CH4 is made in your favorite pond Dr. Ralph S. Wolfe Definitions Metabolism : the sum total of all reactions which occur in a cell. Two types: catabolism, anabolism. Catabolism : degradation of substrates to generate energy and reducing power. Anabolism : synthesis of complex molecules; consumes energy and reducing power. Thermodynamics Energy can neither be created nor destroyed Phototrophs harness light energy into ATP and NADH Chemotrophs transfer energy from chemicals to ATP Basic concepts Systems tend to become disordered (higher entropy) Life is a constant struggle against high entropy Living systems are ordered. Cells use energy to maintain order The second law (entropy) All reactions can be described by the following equation. H = G + T S H (enthalpy) is the total energy of a reaction. S (entropy) is the amount of energy that is lost disordering the system and is not available for work G is the amount of free energy available to do work Gibbs free energy ( G) G = H - T S An increase in entropy (S) disorders the system, giving a negative G. This is a favorable reaction (starch breakdown ) A decrease in entropy (S) results in an ordering of a system and a positive G. ( peptidoglycan synthesis ) Rearrange the equation Where R is the gas constant T is the temperature Keq is the equilibrium constant of the reaction An example reaction Equilibrium is important Changing concentration Changing the concentration of substrates (A and B) or products (C or D) affects the reaction Increasing A and B will drive a reaction Decreasing C and D will drive a reaction Reactants in motion Two substrates One product Redox couple: Oxidation-reduction reactions (redox reactions) Another way of looking at it: X Y 2e- (oxidation) 2e- (reduction) oxidant + 2e- = reductant For example: FAD+/FADH2 Redox...
View Full Document

Page1 / 58

lect 12 - Microbial Energetics Learning goals Learn about...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online