Transcript Slide 1
Biology The Working Cell: Energy From Food Sunlight Powers Life There are 2 main types of organisms: 1. Autotrophs are organisms that make their own food from CO2 and an energy source such as sunlight. Ex Plants, algae, and some bacteria. • Autotrophs are the producers b/c they produce their own food & food for other organisms (they do NOT produce their own energy). http://www.google.com/imgres There are 2 types of autotrophs: • Photoautotrophs: organisms that use sunlight (photosynthesis) to produce their own food (plants, algae, and some bacteria). http://ashraf.shafaki.googlepages.co m/palm-tree.jpg/palm-tree-full.jpg http://gas2.org/files/2008/03/algae2.jpg http://www.clcbio.com/scienceimages/cya nobacteria.png • Chemoautotrophs: organisms that use inorganic chemicals/compounds (chemosynthesis) to produce their own food (bacteria). http://jk169.k12.sd.us/images/Escherichia _coli1355024.300a%5B1%5D.jpg Heterotrophs are organisms that cannot produce their own and must consume (eat other organisms); therefore they are consumers. Ex animals, fungi, and many unicellular organisms. http://worldanimalfoundation.homestead. com/000802_c824_0023_csls.jpg http://faculty.mccfl.edu/rizkf/OCE100 1/OCEnotes/shark2.jpg • All organisms perform some type of cellular respiration – Conversion of sugar & O2 into usable chemical energy (ATP) – By-products are CO2 & H2O http://www.tomatosphere.org/teacher-resources/teachers-guide/grades-8-10/images/photosynthesis-respiration.jpg Energy Terms: • Kinetic energy: energy of motion • Potential energy: stored energy • Thermal energy: random molecular motion; when transferred produces heat • Chemical energy: form of potential energy (macromolecules & ATP) • Calorie: amount of energy needed to raise the temp of 1 g of H2O by 1˚C; kilocalories = 1,000 cal • Cellular respiration is a slow ‘burn’ where heat is produced. ATP • Life depends on energy. Compounds that store energy: ATP, NADPH, NADH, & FADH2. • ATP= adenosine triphosphate is the energy currency of the cell (cash of the cell; main energy of the cell for chemical reactions) • Every time a bond holding a phosphate group (PO3) is broken energy is released; therefore every time ATP losses a PO3, energy is released. • ATP can be used for ALL types of cellular work. ATP is constantly needed b/c cells are constantly working. ATP is continuously broken down and recycled very rapidly (used and remade). Energy for chemical reactions Energy from chemical reactions http://library.thinkquest.org/C006669/media/Biol/img/atp_cycle.gif Cellular Respiration • Cellular Respiration is the process of breaking down glucose molecules through a series of steps to release energy. – This produces ATP. – Occurs in the mitochondria • This can occur in the presence of O2 (aerobic respiration) or without O2 (anaerobic respiration). • Aerobic respiration produces 36 ATP molecules whereas anaerobic respiration produces only 2 ATP. The overall equation of cellular respiration: C6H12O6 + 6 O2 6CO2 + 6H2O + energy • Metabolism: all of the cell’s chemical reactions http://www.google.com/imgres Mitochondria (Sing. Mitochondrion) •Double membrane (outer & inner); both involved in cellular respiration •Cristae: folds of inner membrane (increasing surface area) •Matrix: space within the inner membrane http://www.cartage.org.lb/en/themes/sciences/zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Mitochondria/mitochondria.jpg There are 3 Phases of Aerobic Respiration: 1. Glycolysis: • Whether the organism is aerobic or anaerobic, that organism will undergo glycolysis. This is always the 1st step! • Glucose is converted to pyruvate (a 3-C compound) and 2 ATP are released. • This occurs in the cytoplasm • This occurs in 10 steps; 2 phases • The final results are: 2 NADH, 2 ATP, and 2 pyruvate 2. Krebs Cycle: • This is a.k.a. the citric acid cycle • Pyruvate is converted into acetyl-CoA and CO2 is released • Acetyl-CoA enters the Krebs cycle • This occurs in the mitochondria (matrix) • 2 ATP, NADH, and FADH2 are released. • For every glucose molecule, 2 pyruvate are produced. • 1 ATP is made for each pyruvate; therefore a total of 2 ATP are made. 3. Electron Transport: • Both NADH and FADH2 enter the electron transport • This occurs in the mitochondria (cristae) • This is the only part that REQUIRES OXYGEN. • Prior to this ONLY 4 ATP have been made, yet a total of 36 ATP can be made during aerobic respiration. That means 32 ATP can be made here. This is the cash cow of cellular respiration! • Energy is transferred from NADH and FADH2 to ATP. • Water is produced as a by-product as well as heat. http://fig.cox.miami.edu/~cmallery/150/makeatp/c9x6cell-respiration.jpg Anaerobic Respiration (w/o O2): • Fermentation is the extraction of energy from pyruvate without O2. • Alcohol fermentation is the conversion of pyruvate to CO2 and ethanol (yeast, a unicellular fungi, performs this). • Lactic acid fermentation is the conversion of pyruvate to lactic acid during strenuous exercise when there isn’t enough O2 (animal muscle cells perform this). – This is why muscles become fatigued and sore after strenuous exercising. • Calories are the amount of heat energy needed to raise the temperature of 1 gram of water 1 degree C. – This is the energy contained in food substances. http://www.google.com/imgres THE END! • • This slide show was developed by Dana Halloran, Cardinal Mooney High School, Sarasota, FL. • • • Used with her personal permission, adapted and amended by Rosa Whiting, Manatee School for the Arts, Palmetto, FL.