Cellular Respiration

How do living things get energy? Living things get the ENERGY they need from the breakdown of glucose (sugar) ATP=Energy

Question: In what kinds organisms does cellular respiration take place?

Cellular respiration take place in Plants and Animals Plants – Autotrophs: self-producers. Animals - Heterotrophs: consumers.

Cellular Energy All organisms need a source of energy. Heterotrophs use the organic compounds in food for energy sources. Before energy in complex carbohydrates can be used by cells, it must be broken down into simple sugars like glucose. This breakdown of glucose is done by our digestive system.

Mitochondria Organelle where cellular respiration takes place. Inner membrane space Matrix Cristae Outer membrane Inner membrane

Cellular Respiration

Cellular Respiration C6H12O6 + 6O2  6CO2 + 6H2O + energy The process that releases energy (ATP) by breaking down food molecules in the presence of oxygen. Requires food molecules ex: Glucose (sugar) and Oxygen. Gives off carbon dioxide, water, and Energy. C6H12O6 + 6O2  6CO2 + 6H2O + energy glucose ATP

Summary All our cells need energy ATP is the energy that the cells use for all life processes. The cell makes ATP by breaking down a sugar called glucose. Glucose is the energy of the body. ATP is the energy of the cell

Steps in cellular respiration Step one: is always Glycolysis. Glyco = sugar : lysis= breaking/ split Glycolysis is splitting glucose Step two: depends on whether oxygen is present or not.

Step One Glycolysis Glycolysis is the process in which one molecule of glucose (6 Carbons) is broken “in half”, producing two molecules of pyruvic acid, a 3-carbon compound. Occurs in CYTOPLASM of cell. Video Clip

Glycolysis 2 ATP needed to begin glycolysis. 4 ATP produced when its done. NET gain 2 ATP. (4 – 2 = 2) NADH is an electron carrier. Glycolysis starts w/ ONE GLUCOSE Ends with TWO PYRUVIC ACID Video clip

Step Two Oxygen Present or not? (No) If oxygen is not present (anaerobic) Step two is Fermentation (Yes) If Oxygen is PRESENT (aerobic) step two is the Krebs Cycle & Electron Transport Chain

Fermentation (without oxygen) Chemical Pathways Glucose Krebs cycle Electron transport Glycolysis Alcohol or lactic acid Fermentation (without oxygen)

Oxygen is not present. Fermentation: Two types of fermentation 1. Alcoholic Fermentation Used by Yeast and a few other microorganisms. Produces alcohol and carbon dioxide from the three carbon pyruvic acid. 2. Lactic Acid Fermentation Used by Bacteria and human muscle cells. Produces lactic acid from the three carbon pyruvic acid.

Oxygen is present Krebs Cycle- Step 2 Electron Transport Chain- Step 3 Occurs in mitochondria (matrix) 2 molecules of ATP is generated per glucose. CO2 is produced and released. Electron Transport Chain- Step 3 Takes place in mitochondria (inner membrane). 32 molecules of ATP are produced per glucose molecule.

Krebs Cycle (Step 2 oxygen) When oxygen is present such as in muscles, step two in cellular respiration is the Krebs Cycle Occurs in mitochondria Pyruvic acid is changed in a series of reactions. These reactions produce high-energy electron carriers to be used in the electron transport chain NAD+ and FAD+ are the high energy electron carriers H+ is the electron that needs to be carried. They turn into NADH and FADH2 when carrying electrons and provide the energy to drive the Electron Transport Chain. 2 molecules of ATP is generated per glucose. CO2 is produced and released.

Electron Transport Chain (Step 3 Oxygen) Takes place in mitochondria (inner membrane). Series of proteins accept high energy electron pairs from NADH and FADH2. NADH and FADH2 (Energy taxi dropping off energy) Oxygen bonds with 2 hydrogens (final electron acceptor) to form H20 32 molecules of ATP are produced per glucose molecule.

ATP TOTAL ATP YIELD 02 ATP –Glycolysis 02 ATP Krebs 32 ATP - ETC 36 ATP - TOTAL Net ATP

In Mitochondria with oxygen present In Cytoplasm NADH and FADH2 Krebs Cycle Electron Transport Glycolysis 2 ATP 2 ATP 32 ATP

Electrons carried in NADH in NADH and FADH2 Pyruvic acid Glucose Glycolysis Cytoplasm Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria. Mitochondrion 2 2 32

ADP  ATP Energy Released Video Clip

Summary Step one is always glycolysis. Step two depends on whether or not oxygen is present. If it is not, then step two is fermentation, (anaerobic respiration) If it is, then step two is the Krebs Cycle and step 3 is the electron transport chain. In the process, organic glucose is converted to inorganic CO2

If oxygen is present, its called Aerobic respiration, and 36 ATP are created. During anaerobic respiration or fermentation, 2 ATP are created. ATP is the universal energy molecule, meaning that all living organism use it as an energy source. Notice that much more ATP is made when oxygen is present.

How does glucose get into the body? Through the foods you eat. You eat a piece of bread, which is made of large carbohydrate molecules. Your body breaks the large carbs into tiny sugars during digestion. It starts with the saliva in the mouth, then in the stomach and finally as the food passes through intestines. When the carbs reach the large intestines, they are broken down so small that they get absorbed in the blood. The small sugars are monosaccharides Glucose is one of these monosaccharides. The red blood cells then carry the small sugars to the cells that need them.

Identify the cellular process that most likely produced the CO2 in the body cell Explain why carbon dioxide moves into red blood cells by diffusion rather than active transport.