Biology 4A-3 Cellular Respiration

Start-Up Get out your homework With a partner, complete the following chart for the term Cellular Respiration Objectives:  Define Cellular Respiration  Differentiate between aerobic and anaerobic respiration  Summarize the major events in glycolysis, the citric acid cycle, and the electron transport chain  Compare and contrast alcoholic and lactic acid fermentation Term Written Definition Visual Representation

Cellular Respiration The breaking down of a food substance into usable cellular energy in the form of ATP Cellular respiration can be aerobic (requiring oxygen) or anaerobic (not requiring oxygen) Most cells perform aerobic respiration

Glycolysis Takes place in the cytoplasm It does not require oxygen so the process is ___________?

Glycolysis- The Steps Step 1: 2 molecules of ATP are used to attach 2 phosphate groups onto the glucose molecule. The new molecule is broken down into 2-3 carbon molecules of PGAL

Glycolysis- The Steps Step 2: Each PGAL molecule releases electrons and hydrogen ions to an electron carrier molecule and each PGAL molecule has a phosphate attached to it, forming a new 3-carbon compound

Glycolysis- The Steps Step 3: The phosphate groups added in steps 1 and 2 are removed and added to a molecule of ADP, forming a total of 4 ATP molecules

The Citric Acid Cycle Read A closer Look on Page 107

Electron Transport Chain Step 1 and 2: Electron and hydrogen carrier molecules release their high energy electrons to an accepter molecule, which passes electrons through the chain Some of the energy released is used to pump hydrogen ions in the outside of the membrane

Electron Transport Chain Step 3: at the end of the chain, the electron are released into the mitochondria, where they combine with hydrogen and oxygen to form water

Electron Transport Chain Step 4: chemiosmosis- the H ions pass through a molecule of ATP synthase, releasing energy that powers the reproduction of ATP from ADP and phosphate

Electron Transport Chain Step 5: the electrons from step 3 and the incoming hydrogen ions from step 4 combine with oxygen to form water

Alcoholic Fermentation The pruvic acid molecule is changed to a molecule of ethyl alcohol in a two step process Step 1: Pruvic Acid gives off a carbon dioxide molecule, converting it to a 2-carbon compound Step 2: the 2-Carbon compound takes the hydrogen ions and electrons to form ethyl alcohol

Lactic Acid Fermentation Has only one step  Pyruvic acid takes the hydrogen and electrons from the NADH produced during glycolysis, freeing the transfer molecule to be used again in glycolysis to produce ATP

Need To Know