Cellular Respiration 1

The process by which glucose is converted is into carbon dioxide, water, and ENERGY + O 2 CO 2 + H 2 O + Energy

Comparing Combustion to Respiration

Review of Terminology Oxidation- loss of electrons - gain of oxygen - loss of hydrogen Reduction- gain of electrons - loss of oxygen - gain of hydroven

Review of Terminology Oxidation- loss of electrons - gain of oxygen - loss of hydrogen - ON more positive Reduction- gain of electrons - loss of oxygen - gain of hydrogen - ON less positive REDOX reaction

Review of Terminology aerobic- with O 2 anaerobic- without O 2

Stage One - Glycolysis Anaerobic 1 mol glucose  2 mol pyruvate C 6 H 12 O 6 + 2NAD +  2 C 3 H 3 O NADH + 4H + + energy

Stage One - Glycolysis Anaerobic 1 mol glucose  2 mol pyruvate C 6 H 12 O 6 + 2NAD +  2 C 3 H 3 O NADH + 4H + + energy oxidation reduction

NAD + and NADH

Glycolysis

Stage Two – Aerobic or Anaerobic Respiration Aerobic or Anaerobic respiration follows depending on whether O 2 is available or not. Pyruvate O2O2 CO 2 + H 2 O aerobic respiration No O 2 lactic acid anaerobic respiration Ethanol anaerobic respiration

Aerobic Respiration Redox Reaction: 2 C 3 H 3 O NADH + 4H + + 6O 2  6CO 2 + 6H 2 O + 2NAD + pyruvate

Overall Reaction Adding together the rxns for Stage One and Stage Two gives the overall reaction …. Stage One C 6 H 12 O 6 + 2NAD +  2 C 3 H 3 O NADH + 4H + + energy Stage Two 2 C 3 H 3 O NADH + 4H + + 6O 2  6CO 2 + 6H 2 O + 2NAD + C 6 H 12 O O 2  6 CO H 2 O ∆ H = kJ/mol equivalent to 36 ATP

The Half Reactions The overall redox rxn for aerobic respiration is made up the following two half rxns: oxidation half reaction (C gets oxidized) C 6 H 12 O H 2 O  6CO H e reduction half reaction (O gets reduced) 6O H e  12H 2 O C 6 H 12 O O 2  6 CO H 2 O

Aerobic Pathway for Pyruvate

The Role of Fe and Cu Fe and Cu in cytochromes are involved in moving the electrons produced in the oxidation step to the reduction step this occurs in the Electron Transport Chain coupled to the oxidation step is a reduction involving Fe or Cu: Fe 3+ + e  Fe 2+ or Cu 2+ + e  Cu + coupled to the reduction step is an oxidation involving Fe or Cu: Fe 2+  Fe 3+ + e or Cu +  Cu 2+ + e

Energy Output Goal – release the energy from glucose to fuel cell processes -ATP is an energy storage molecule like a battery -The conversion of ATP  ADP releases stored energy (30.5 kJ/mol)

Energy Output Exothermic Endothermic

Energy Tally

Anaerobic Respiration occurs during strenuous exercise when enough O 2 is not available for aerobic respiration lactic acid is produced which causes muscle cramping the overall redox reaction is: C 3 H 3 O NADH + H +  C 3 H 5 O NAD + + energy as 2 ATP Pyruvate Lactate The two half rxns that make up this redox rxn are:

Anaerobic Respiration occurs during strenuous exercise when enough O 2 is not available for aerobic respiration lactic acid is produced which causes muscle cramping the overall redox reaction is: C 3 H 3 O NADH + H +  C 3 H 5 O NAD + + energy as 2 ATP Pyruvate Lactate oxidation half reaction NADH + H +  NAD e + 2 H + reduction half reaction C 3 H 3 O e + 2H +  C 3 H 5 O 3 -

Anaerobic Respiration Eventually O 2 will again be available and the lactic acid will get oxidized to make CO 2 and H 2 O by this overall redox reaction: C 3 H 6 O O 2  3 CO H 2 O + energy Lactic acid conjugate acid for lactate ion

Fermentation a form of anaerobic respiration that occurs in yeast pyruvate is converted in ethanol 2 C 3 H 3 O NADH + 4H +  2 CH 3 CH 2 OH + 2CO 2 + 2NAD + adding the glycolyis reaction and this reaction gives the overall fermentation reaction: C 6 H 12 O 6  2 CH 3 CH 2 OH + 2 CO 2

Two Anaerobic Pathways

Summary of the Aerobic and Anaerobic Pathways

Transport Processes in Cellular Respiration 1) Electron Transport Chain cellular respiration involves redox reactions the Electron Transport Chain involves the movement of e’s in these redox reactions at the same time ADP gets released as ATP (energy out) Cytochromes are Fe and Cu containing protein molecules that can shuttle around e’s (see aerobic respiration above)

A Cytochrome Molecule

Transport Processes in Cellular Respiration 2) O 2 Transport in the Blood Haemoglobin is an oxygen transport protein it consists of 4 heme groups:

Haemoglobin O 2 gets moved through the blood by forming a dative bond with the iron in the heme group CO and CN - preferentially form dative bonds with the Fe in the heme group blocking the site from oxygen  carbon monoxide poisoning or cyanide poisoning

Videos How NAD works Glycolysis ATP