Cellular Respiration Harvesting Energy From Food Chapter 7

ATP provides the energy for cellular work ATP: (adenosine triphosphate) main energy source that cells use for most of their work An ATP molecule contains potential energy, much like a compressed spring. When a phosphate group is pulled away during a chemical reaction, energy is released.

The ATP Cycle ATP is constantly recycled in your cells. A working muscle cell recycles all of its ATP molecules about once each minute. That's 10 million ATP molecules spent and regenerated per second!

Overall Equation for Cellular Respiration In cellular respiration, the atoms in glucose and oxygen are rearranged, forming carbon dioxide and water. The cell uses the energy released to produce ATP.

Cellular respiration breaks down organic molecules to yield energy. Energy stored in organic compounds is released in a series of enzymes controlled reactions. Similar to burning but…

In Eukaryotic Cells, the reaction of Aerobic Respiration occur Inside MITOCHONDRIA.

Structure of Mitochondria Mitochondria are found in almost all eukaryotic cells. Its structure is key to its role in cellular respiration. Its complex folding pattern of membranes and spaces allows for many sites where reactions can occur.

Respiration involves glycolysis, the Krebs cycle, and electron transport Step 1 Step 2 Step 3 2 2 32- 34

GLYCOLYSIS The first stage in breaking down a glucose molecule, called glycolysis (splitting sugar), takes place outside the mitochondria in the cytoplasm of the cell. releases a small amount of energy. It is the first step in cellular respiration. If oxygen isn’t present a different pathway is followed

Stage I: Glycolysis The first stage in breaking down a glucose molecule, called glycolysis (splitting sugar), takes place outside the mitochondria in the cytoplasm of the cell.

Stage 2: The Krebs Cycle The Krebs cycle finishes the breakdown of pyruvic acid molecules to carbon dioxide, releasing more energy in the process. The enzymes for the Krebs cycle are dissolved in the fluid matrix within a mitchondrion's inner membrane.

Kreb’s Cycle: Where does this occur? Identify the products. Kreb’s Cycle movie

Stage 3: Electron Transport Chain and ATP Synthase Action The final stage occurs in the inner membranes of mitochondria. This stage has two parts: an electron transport chain and ATP production by ATP synthase

The Pathway of Electron Transport  The inner mitochondrial membrane couples electron transport to ATP synthesis. The Pathway of Electron Transport This energy change is used to “pump” hydrogen to the inner membrane space creating a gradient which can power cell processes. .

Chemiosmosis couples the electron transport chain to ATP synthesis

Chemiosmosis: The Energy-Coupling Mechanism ATP synthase protein complex functions as a mill, powered by the flow of hydrogen ions. This complex resides in mitochondrial and chloroplast membranes of eukaryotes and in the plasma membranes of prokaryotes.. The gradient of hydrogen ions “pushes” the ATP synthesis.

Animation of ATP synthesis in Mitochondria Copyright 1997. Thomas M. Terry, The University of Connecticut

Cellular respiration generates many ATP molecules for each sugar molecule it oxidizes During respiration, most energy flows in this sequence: Glucose NADH  electron transport chain  protonmotive force  ATP

Harvesting Energy without Oxygen Fermentation in Human Muscle Cells When your lungs and bloodstream can't supply oxygen fast enough to meet your muscles' need for ATP. Your muscle cells use fermentation, to make ATP without using oxygen. How does the energy production of Lactic Acid fermentation compare to aerobic respiration?

Lactic Acid fermentation occurs in animal cells deficient in oxygen Lactic Acid Fermentation movie

Fermentation in Microorganisms Yeast (a microscopic fungus) is capable of both cellular respiration and fermentation. Fermentation in yeast produces ethyl alcohol. The carbon dioxide that is released during fermentation creates bubbles and pockets that make bread rise. The alcohol evaporates during baking.

Fermentation enables some cells to produce ATP without the help of oxygen. Alcoholic fermentation occurs in yeast. Alcoholic Fermentation movie

Pyruvate as a key juncture in catabolism Pyruvate as a key juncture in catabolism. Glycolysis is common to fermentation and respiration. How does the net gain of ATP compare in aerobic vs. fermentation?

The catabolism of various food molecules The catabolism of various food molecules. Carbohydrates, fats, and proteins can all be used as fuel for cellular respiration.

WITH OXYGEN Cellular respiration is the process _________________________________________________________________________________ It is composed of Glycolysis _______________________