Bio 178 Lecture 15 Cellular Respiration http://biology.clc.uc.edu/courses/bio104/cellresp.htm

? Reading Quiz Material Chapter 9 Questions on P 184 Chapter 9 Quizzes on Text Website (www.mhhe.com/raven7)

Outline Cellular Respiration Glucose catabolism

ATP Synthase

Glucose Catabolism Methods for Making ATP 1. Substrate-Level Phosphorylation ADP + Pi  ATP Pi comes from a phosphate-bearing intermediate molecule. Example - Glycolysis. 2. Aerobic Respiration ATP synthase makes ATP using energy provided by electron transfer. O2 = final electron acceptor.

Substrate-Level Phosphorylation

Aerobic Respiration

Processes Involved in Eukaryotic Respiration 1. Glycolysis Sugar splitting anaerobic process. Location Cytoplasm Energetic Products 2 ATP net & 2 NADH net produced by substrate level phosphorylation. 2. Aerobic Respiration Pyruvate oxidation Krebs cycle Electron transport chain

Glycolysis 1. Glucose Priming 2. Cleavage 3. Energy Harvesting Glucose + 2 ADP + 2 Pi + 2 NAD+  2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O 10 enzyme catalyzed steps can be divided up into 3 major stages: 1. Glucose Priming Glucose is prepared for cleavage using 2 ATP. 2. Cleavage Fructose 1,6-bisphosphate (6C)  2 X 3C molecules. 3. Energy Harvesting The 2 X 3C molecules are converted into 2 pyruvate (3C), releasing 2 NADH and 4 ATP by substrate-level phosphorylation.

Principle Stages of Glycolysis

Glycolysis Pathway

Glycolysis Pathway

Glycolysis (Cntd.) Bookkeeping NAD+ Regeneration 1. ATP 4 ATP - 2 ATP = 2 ATPnet 2. NADH 2 NADH NAD+ Regeneration Glycolysis depletes cellular NAD+ stores. The cell uses 2 methods to recycle NAD+ (transfer electrons and H+): Aerobic respiration Fermentation

Pyruvate Fate

Allows glycolysis to continue in the continued presence of glucose. Fermentation Allows glycolysis to continue in the continued presence of glucose. 2 types: Ethanol - Yeast 2 Pyruvate (3C)  2 Acetaldhyde (2C) + 2 CO2  2 Ethanol (2C) (+ 2 NAD+) Toxic to yeast at 12% Lactic Acid - Animals 2 Pyruvate (3C)  2 Lactate (3C) (+ 2 NAD+) When lactate is produced faster than it is removed  Muscle fatigue

Fermentation

Acetyl-CoA Production Function Oxidation of pyruvate to produce NADH Acetyl-CoA used either in fat synthesis or ATP generation Overall Reaction Pyruvate (3C) + CoA + NAD+  Acetyl-CoA (2C) + CO2 + NADH Catalyzed by pyruvate dehydrogenase Coenzyme A is a cofactor Location Pyruvate is shuffled into the mitochondrion. Acetyl co-A is made in the mitochondrial matrix.