2 Main Idea: Living organisms break down organic molecules (food) in the presence of oxygen during cellular respiration to get energy.C6H12O6 + 6O2 -> 6CO2 +6H2O + EnergyKnow this equation! What are the reactants and what are the products?
3 2 Main Parts: Anaerobic (without oxygen) Glycolysis Lactic Acid FermentationAlcohol FermentationAerobic (with oxygen)Krebs CycleElectron Transport
4 Let’s start with Glycolysis What is glycolysis?Breakdown of glucose in the cell’s cytoplasmPage 229 in your book- Figure 8.12Glucose is broken down into 2 three-carbon molecules. (2 ATP are used)NAD+ becomes NADH (electron carrier)2 three-carbon molecules become 2 pyruvate and 4 ATP are produced.
5 What are the net products of glycolysis? 2 Pyruvate2 ATPWhy not 4 ATP?Because 2 ATP are used to start the reaction so only a net of 2 ATP are produced.
6 Krebs CyclePyruvate converted to CO2 in the mitochondrial matrix. ATP, NADH, and FADH2 are produced.Page 230 Figure 8.13Acetyl CoA formedAcetyl CoA moves to mitochondrial matrix and combines with a 4-carbon compound: Citric Acid madeCitric Acid Broken downAcetyl CoA and citric acid are generated and the cycle begins again.
9 RememberFor every glucose molecule there is 2 turns of the Krebs cycle.What is the net yield of products of the Krebs cycle?6 CO22 ATP8 NADH2 FADH2
10 Electron Transport Final Step in breakdown of glucose Happens in the mitochondrial membranePage 230 figure 8.14NADH and FADH2 release electrons & H+ becoming NAD+ and FADH+ is pumped into the intermembrane space across the inner membraneH+ diffuses back across membrane into matrix (chemiosmosis)O2 is the final electron receptorProtons and e- are transferred to oxygen to form H2O
11 In Eukaryotes 1 molecule of glucose gives us 36 ATP From what cycles are these ATP produced and how many are produced in each cycle?Glycolysis 2 ATPKrebs 2 ATPElectron Transport 32 ATPATP is used to provide energy for the cell
12 In Prokaryotes cellular respiration No Mitochondria so there are differencesElectron transport happens in the cellular membraneBecause we don’t have to move pyruvate to the mitochondria in prokaryotes 2 ATP are “saved”.Net total ATP = 38Why are 2 more ATP produced in prokaryotic cellular respiration than in eukaryotic cellular respiration?
13 Anaerobic Respiration Without oxygenGlycolysisLactic Acid FermentationAlcohol Fermentation
14 Fermentation Occurs in the cell’s cytoplasm It regenerates ATP and produces small amount of ATPLactic Acid FermentationPyruvate converted to lactic acid with help of enzymesSkeletal muscles produce lactic acid when O2 supply is lowSome microorganisms produce lactic acid -> used in cheese, yogurt, sour creamAlcohol Fermentation: pyruvate converted to ethyl alcohol and CO2