Download
1 / 22
220 likes | 221 Vues
Cellular Respiration and Photosynthesis. Cellular Respiration. . Definition : The controlled release of energy from organic compounds (like glucose) in cells to form ATP. Energy . Forms of energy are important to life and include chemical, radiant, and electrical.
E N D
Cellular Respiration . Definition: The controlled release of energy from organic compounds (like glucose) in cells to form ATP.
Energy • Forms of energy are important to life and include chemical, radiant, and electrical. • Energy can be transformed from one form to another. • Chemical energy is the energy found in the chemical bonds of molecules.
ATP • Adenosine Triphosphate. • Energy carrying molecule used by cells to fuel their cellular processes. • When phosphate bonds are broken, energy is released. • When phosphate bonds are formed, ATP is made (synthesized). • ATP is composed of: • Adenine base • Ribose sugar • 3 phosphate groups
The Mitochondria Has a smooth outer membrane and folded inner membrane. Folds in the membrane are called CRISTAE. Space inside the cristae is called the MATRIX. Site of aerobic cellular respiration. -Krebs cycle takes place in the matrix. -Electron Transport Chain takes place in the cristae.
ATP/ ADP Cycle ATP +P -P A phosphate group is added. The energy to do this is provided by glucose during cellular respiration. ENERGY IS ABSORBED! A phosphate group is ‘kicked off’ to release energy for cell processes (cell metabolic activities). ENERGY IS RELEASED! ADP
Energy Carrying Molecules During Cellular Respiration • NAD:Nicotinamide Adenine Dinucleotide • FAD:Flavine Adenine Dinucleotide • Both molecules carry energy in the form of H+ (hydrogen ions) from one step of the process to the next. • This is temporary… eventually the energy that they carry will be used to synthesize ATP!
Redox Reactions • Reactions that involve one substance losing electrons and another gaining electrons. • A)Reduction = the substance that gains electrons • B) Oxidation = the substance that loses electrons • C) Cellular Respiration involves many Redox reactions; NAD and FAD molecules are directly involved in these reactions.
Two Types of Cell Respiration AEROBIC ANAEROBIC • Produces energy in the form of ATP. • Oxygen is necessary. • 36 ATP are produced for every 1 glucose molecule. • Carbon dioxide is a waste product. • Occurs in the cytoplasm and mitochondria • Produces energy in the form of ATP. • Oxygen is not necessary. • 2 ATP are produced for every 1 glucose molecule. • Carbon dioxide a product in some • ethyl alcohol or lactic acid are waste products. • Occurs in just the cytoplasm.
Anaerobic Respiration • ATP production without oxygen present. Involves the first step of Aerobic Respiration (called glycolysis). • A) 2 ATP are inputed to split glucose into (2) 3-carbon compounds called PHOSPHOGLYCERALDEHYDE (PGAL). • B) NADH carries the energy along, eventually producing 4 ATP. • C) 2 Pyruvates are produced, a net gain of 2 NADH, (2) CO2, and a net gain of 2 ATP.
Anaerobic Respiration Cont. • D) In Yeast cells, the pyruvates eventually lose 1 more CO2 and produce ethyl alcohol. • E) Occurs in the cytoplasm; also called fermentation. • F) In Muscle Cells, the pyruvates are converted into lactic acid.
Aerobic Respiration • ATP production in the presence of oxygen. It is a four step process… • 1) Glycolysis • in the cytoplasm • yields a net gain of 2 ATP • 2) Transition Reaction • converts (2) Pyruvic Acid into (2) Acetyl CoA • Starts in the cytoplasm and continues into mitochondria. • 3) The Krebs Cycle (aka Citric Acid Cycle) • two turns per original glucose that entered glycolysis • occurs in the mitochondrial matrix • yields 2 ATP • 4) The Electron Transport Chain • occurs in the mitochondrial membrane or cristae • yields 32 ATP • relies on H+ concentration gradient
Glycolysis • 1. In the cytoplasm, 2 ATP are used (invested) to energize glucose, and split the molecule in two. • 2. (2) PGAL result. • 3. (2)H+ are taken from each PGAL to make (2)NADH. • 4. Each PGAL are rearranged into Pyruvate (pyruvic acid) with energy transferred to make 4ATP.
Step #2: Transition Reaction Each pyruvic acid from glycolysis diffuses into the matrix of the mitochondria and reacts with coenzyme A (CoA) to form Acetyl CoA (a 2-carbon compound). Carbon dioxide and NADH are also produced. Each of the Acetyl CoA will then enter the Krebs Cycle.
Step #3: The Krebs Cycle • Metabolic pathway that requires oxygen. • Also know as the Citric Acid Cycle. • Requires 2 turns of the cycle for each original glucose that entered glycolysis. • Acetyl CoA enters the Krebs Cycle and joins with Oxaloacetic Acid to make citric acid. • Along the cycle 3NADH2, 1FADH2, 2 Co2, and 1ATP are made (remember…. 2 turns!!!) • Oxaloacetic acid is regenerated, and electrons carriers migrate to the Electron Transport Chain.
Step #4: The Electron Transport Chain • H+ ions brought from the Krebs Cycle pass through the inner membrane proteins of the mitochondria. • The H+ build in concentration between the inner and outer membranes. • H+ diffuse from the space between the membranes and back through the inner membrane (cristae). The energy they bring (utilizing ATP synthase) produces ATP through attaching a 3rd phosphate to ADP. • Oxygen is the final electron (hydrogen)acceptor, forming water.
