Cellular Respiration
Cellular Respiration Cellular respiration breaks down glucose molecules to release ATP This is an aerobic process- it requires oxygen Takes place in the mitochondria Breaking down food to produce energy is a two-part process: Glycolysis (anaerobic- doesn’t need oxygen) in the cytoplasm Respiration- aerobic, takes place in the mitochondria
Cellular Respiration Cellular respiration is basically the opposite of photosynthesis Photosynthesis requires CO2 and water to produce oxygen and sugar Cellular respiration requires sugar and oxygen to produce CO2 and water
Glycolysis Takes place in the cytoplasm Does not require oxygen A 6-carbon glucose is split into two 3-carbon molecules using up two molecules of ATP. A series of reactions produces two NADH molecules and four ATP molecules. The 3-carbon molecules are rearranged to form molecules called pyruvate, which enters cellular respiration.
Cellular Respiration Two parts: Krebs cycle- in the mitochondrial matrix Electron transport chain- in the membrane
Krebs Cycle Pyruvate molecule is broken down Krebs cycle turns twice and produces 6 CO2 waste given off 2 ATP 8 molecules of NADH and 2 FADH2 to electron transport chain (next step)
Krebs Cycle
Electron Transport Chain Electrons from NADH and FADH2 enter the electron transport chain. Energy from the electrons is used to pump H+ ions across mitochondrial membrane. They build up inside the membrane. H+ ions flow through a protein channel called ATP synthase, producing ATP from ADP. Water is formed and given off as a waste product.
Electron Transport Chain 2. H+ ions transported across membrane 3. ATP is produced by H+ ions flowing through ATP synthase 4. Water is formed 1. Electrons removed from NADH and FADH2
Products of Glycolysis and Respiration CO2 molecules Water molecules Up to 38 ATP molecules 2 from glycolysis 2 from Krebs cycle 34 from electron transport chain
Fermentation Cellular respiration requires oxygen What happens if cells run out of oxygen? Instead of continuing on to cellular respiration after glycolysis, the cell will go through the process of fermentation.
Fermentation Fermentation can be either lactic acid or ethanol (alcohol) Fermentation does not produce ATP, but it allows glycolysis to continue Glycolysis provides a small amount of energy