Cellular Respiration Where the fuel is burned.

Mitochondria  Double membrane bound organelle.  Outer membrane encloses the entire structure.  Inner membrane encloses a fluid-filled matrix.  Folded cristae project into the matrix. Increases surface area  Small circular DNA.

Mitochondria  It is the site of cellular respiration,  a catabolic, “breaking down”,  Exergonic, “energy releasing”,  Aerobic: “oxygen requiring” process that uses energy extracted from glucose to produce ATP.

ATP  Energy is released from ATP when a phosphate group is removed.  ATP is changed to ADP.  ADP can then be “recharged” to ATP again.

Overall Reaction: C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + 36 ATP + Heat  Do the products and reactants look familiar?

Cellular Respiration Overview  Breakdown of glucose begins in the cytoplasm, the liquid matrix inside of all cells  At this point life diverges into two forms and two pathways  Anaerobic cellular respiration also called: fermentation  Aerobic cellular respiration, commonly just called cellular respiration.

Stages of Cellular Respiration Cellular Respiration can be broken down into three stages: 1.Glycolysis (splitting of sugar) 2.Kreb’s Cycle also known as the Citric Acid Cycle 3.Electron Transport Chain (ETC) also called chemiosmosis

Glycolysis  Occurs in the cytoplasm of all cells  Series of reactions which break the 6- carbon glucose molecule down into two 3- carbon molecules called pyruvate.  Process is an ancient one-all organisms from simple bacteria to humans perform it the same way.  Yields 2 ATP molecules for every one glucose molecule broken down  Yields 2 NADH per glucose molecule

Aerobic Cellular Respiration  Oxygen required = aerobic  2 more sets of reactions which occur in a specialized structure within the cell called the mitochondria  1. Kreb’s Cycle  2. Electron Transport Chain

Kreb’s Cycle

Kreb’s Cycle (Citric Acid Cycle)  Occurs in the mitochondrial matrix  Completes the breakdown of glucose  Takes the pyruvate (3-carbons) and breaks it down, the carbon and oxygen atoms end up in CO 2 and H 2 O  Hydrogens and electrons are stripped and loaded onto NAD + and FAD to produce NADH and FADH2  Production of only 2 more ATP but loads up the coenzymes with H + and electrons which move to the 3 rd stage

Kreb’s Cycle

Electron Transport Chain (ETC)  Occurs along the inner mitochondrial membrane.  Electron carriers loaded with electrons and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase).  As electrons drop down stairs, energy released to form a total of 32 ATP  Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water. Cleans up the area!!

Energy Tally  36 ATP for aerobic vs. 2 ATP for anaerobic  Glycolysis 2 ATP  Kreb’s 2 ATP  Electron Transport32 ATP 36 ATP 36 ATP  Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

ETC Kreb’s Cycle

Releasing chemical energy Use your “Releasing Chemical Energy” worksheet to answer questions from the video.

Kreb’s Cycle

Anaerobic Cellular Respiration: Fermentation  Some organisms thrive in environments with little or no oxygen  Marshes, bogs, gut of animals, sewage treatment ponds  No oxygen used = ‘an’aerobic  Results in no more ATP, final steps in these pathways serve ONLY to regenerate NAD+ so it can return to pick up more electrons and hydrogens in glycolysis.

Alcoholic Fermentation  Products: ethyl alcohol, carbon dioxide and the energy carrier NAD+  Release energy from food molecules by producing 2 ATP molecules.  Yeast: dough rises due to carbon dioxide.  Bacteria: present on grapes creates the alcohol found in wines.

Lactic Acid Fermentation  Product: lactic acid and the energy carrier NAD+  Rapid exercise. Body cannot get enough oxygen.  Run out of oxygen. Produce ATP by lactic acid fermentation causing sore muscles.  Unicellular organisms – lactic acid (waste)  Examples: cheese, yogurt, buttermilk

Photosynthesis / Cellular Respiration Use your “Energy and Chemistry of Life” worksheet to answer questions from the video.