Cellular Respiration PDF

Cellular Respiration OBJECTIVE: Describe how organisms use the aerobic and anaerobic pathway to obtain and utilize energy.  Cellular respiration consists of a series of catabolic reactions that aim to produce ATP from the breakdown of glucose. Adenosine triphosphate or ATP serv...

Cellular Respiration OBJECTIVE: Describe how organisms use the aerobic and anaerobic pathway to obtain and utilize energy.  Cellular respiration consists of a series of catabolic reactions that aim to produce ATP from the breakdown of glucose. Adenosine triphosphate or ATP serves as the primary energy currency of cells. This molecule allows the energy captured in cellular respiration to be transferred to different parts of the cell to power vital reactions.  In cellular respiration, glucose is oxidized, yielding carbon dioxide, while oxygen gets reduced, making it an electron acceptor. ENERGY PATHWAYS FOR CELLULAR RESPIRATION  There are two energy pathways for cellular respiration among animals: aerobic pathway and the anaerobic pathway. Oxygen has a role to play in the aerobic pathway No or little oxygen is needed in the anaerobic pathway.  There are two energy pathways for cellular respiration among animals: aerobic pathway and the anaerobic pathway.  Cells produce energy in the presence Aerobic of oxygen. This metabolism is called Cellular respiration. Cells undergo a series of metabolic reactions with little or no oxygen Anaerobic present. It is also the energy pathway for cells that do not contain mitochondria. AEROBIC PATHWAY The aerobic pathway has three (3) stages. 1. Glycolysis 2. Krebs Cycle 3. Electron transport chain (ETC)  Glycolysis Glycolysis begins by breaking down glucose into pyruvate. This take place in the cytosol in the presence of oxygen and outside the cell’s mitochondria.  Glycolysis Pyruvate is then transferred to mitochondria where it enters the Krebs Cycle. When glucose is broken down into pyruvate, the by-products are 2 adenosine triphosphate molecules (ATP), carbon dioxide, and water. ATP transports chemical energy within cells to support cell metabolism.  KREBS CYCLE The Krebs Cycle is the second stage of cellular respiration. It begins when pyruvate molecules enter the inner matrix of the cell’s mitochondria. The end products are CO2, ATP molecules, NADH, FADH2, and high energy electrons carried by NADH and FADH2.  ELECTRON TRANSPORT CHAIN The electron transport chain is the third stage. High energy electrons captured in the Krebs cycle join with oxygen and hydrogen. This produces 34 of the 38 ATP produced by a complete aerobic metabolism.  ELECTRON TRANSPORT CHAIN Hence, the last stage of the aerobic pathway brings the largest energy output for the cell. (Keep in mind: ATP is the molecule which directly provides energy to cells for its cellular functions.) Glycolysis gives 2 ATP, Krebs Cycle another 2 ATP, and the electron energy chain gives 34 ATP. ANAEROBIC PATHWAYS 1. Glycolysis 2. Fermentation  FERMENTATION During fermentation, enzymes work on pyruvate in the absence of oxygen. Enzymes that speed fermentation are found in the cell’s cytoplasm. The anaerobic pathway produces only 2 ATP molecules and they come solely from glycolysis.  FERMENTATION Fermentation does not produce ATP molecules. It recycles the electron carrier molecules (NADH, and FADH2) needed for glycolysis. Fermentation strips NADH and FADH2 of electrons and hydrogen atoms, making them available for a new round of glycolysis.  TYPES OF FERMENTATION Used by animals and certain Lactic Acid bacteria. The by-product is Fermentation lactic acid and NAD+. Microorganisms like yeast take the alcohol fermentation Alcohol pathway to harvest energy. Fermentation The by-product of this reaction is ethyl alcohol and NAD+. ANAEROBIC RESPIRATION AND FERMENTATION  What are the two energy pathways for cellular respiration? Quick What are the three (3) stages in Answers Aerobic pathway of metabolism and : give their by-products. What are the two (2) stages in Anaerobic pathway of metabolism and give their by-products. Thanks CREDITS: This presentation template was created by Slidesgo, and includes icons by Slidesgo Flaticon and infographics & images by Freepik Flaticon Freepik Please keep this slide for attribution