Cellular Respiration PDF

Cellular Respiration  What is Cellular Respiration? Cellular Respiration can be considered the opposite process of photosynthesis It is the transformation of food energy into chemical energy in the form of ATP Plants and animals go through the same process of cellular respiration ...

Cellular Respiration  What is Cellular Respiration? Cellular Respiration can be considered the opposite process of photosynthesis It is the transformation of food energy into chemical energy in the form of ATP Plants and animals go through the same process of cellular respiration  Photosynthesis vs Cellular Respiration Photosynthesis Respiration Produces food (glucose) Consumes food (glucose) Stores energy Releases energy (ATP) Consumes CO2 Produces CO2 Releases O2 Consumes O2 Light dependent Light independent – Occurs only in plants – Occurs in all living organisms  Reaction Formula Glucose combined Six carbon dioxide with six oxygen molecules and six water molecules molecules, and ATP molecules.  The Two Types of Cellular Respiration Anaerobic Aerobic Occurs when oxygen is not present Occurs in the presence of oxygen (O2) – When O2 is not available, fermentation The process is continued in the occurs in the cytoplasm mitochondria of the cell Results in a) Krebs Cycle – Ethanol and CO2 b) Electron Transport Chain Yeast, beer, and bread – Lactic acid Muscle cells Check Point!  What is the opposite process of Respiration? Remember in photosynthesis that plant cells consume CO2 and produce O2, while at the basic level respiration consumes O2 and produces CO2 __________________________ respiration requires oxygen. If oxygen is not required, the respiration process is called ____________________________. The fermentation process is characteristic of ___________________________ respiration. Glycolysis Occurs in the cytoplasm First step in both aerobic and anaerobic respiration  Oxidation In respiration glucose is oxidized, and energy is released in the form of adenosine triphosphate Oxidation is combining any molecule with a molecule of oxygen (O2). ADP is then further oxidized into the pyruvate  Energy Currency Adenosine triphosphate, otherwise known as ATP is considered to be the major energy source of the cell Energy is released from the conversion of ATP to adenosine diphosphate or ADP ATP is the immediate source of energy in a cell – the more ATP that is produced, the more energy a cell has.  Breakdown of Pyruvate A series of reactions break down the glucose molecule into pyruvate – Pyruvate = two 3-carbon molecules This process yields 2 ATP molecules for each molecule of glucose broken down and 2 NADH molecules  NADH the Electron Carrier NADH is a reduced form of NAD+ –Meaning that the Hydrogen (H+) electron was released NAD+ functions as an electron carrier from one step to the next in the respiration process Where in the cell are we? Check Point!  True or False? Glycolysis only happens during anaerobic respiration Glycolysis occurs during both the anaerobic and aerobic respiration processes  True or False? The breakdown of pyruvate during the glycolysis process yields 2 ATP and 4 NADH molecules Only 2 NADH molecules are produced during glycolysis  Aerobic Respiration is a three step process 1.Glycolysis 2.Krebs cycle 3.Electron Transport Krebs Cycle Oxygen required = aerobic process Occurs in the mitochondria  “Prep” Stage During glycolysis, pyruvate is formed and 2 CO2 molecules are formed as waste products In the preparatory phase of the Krebs cycle the pyruvate is “prepped” into a usable form, known as Acetyl-CoA Acetyl-CoA is produced through the oxidation of pyruvate  Krebs Cycle The cycle is completed or “turned” twice per original glucose molecule 2 ATP molecules and 4 CO2 molecules are gained for each original glucose molecule in the cycle Electron Transport Chain Third step in aerobic respiration Occurs in membrane of mitochondria Electron Transport Chain Electrons that have become “excited” are brought to the ETC by carriers such as NADH and FADH2 This releases the energy that cells need to make the most of their ATP so that it does not go to waste. When the hydrogen ions flow back through the mitochondrial membrane, the energy is released.  Electron Transport Chain: A Closer Look Aerobic Respiration Summary Electron Prep Krebs Glycolysis Cycle Transport stage Chain Check Point! The first step in both aerobic and anaerobic respiration is _________________. The Krebs cycle and the electron transport chain are steps only in ___________ respiration. Acetyl-CoA is produced in the _______ stage of aerobic respiration from the pyruvate molecule. Fermentation Anaerobic respiration process It is the extraction of energy from pyruvate in the absence of oxygen.  Aerobic Respiration vs Fermentation Aerobic Respiration Fermentation – Requires the presence of – Takes place without oxygen and yields more oxygen and yield 2 ATP ATP molecules molecules – Involves changing of gases – Allows some organisms to with other organisms live in place where there is little or no oxygen – Speed in producing ATP molecules – By products: yeast, alcohol  Two types of Fermentation Alcoholic fermentation Lactic acid fermentation – Carried out by yeast and – Carried out by muscles some bacteria when O2 is not absorbed – Results in ethanol and fast enough CO2 Also occurs in the bacteria The trapped CO2 is what found in yogurt causes bread to rise – Results in lactic acid Remember that… Both begin with glycolysis Remember that in anaerobic processes, the pyruvate does not go through the Krebs cycle or through the electron transport chain  ATP Production During anaerobic respiration, only 2 molecules of ATP are produced during the first and essentially only step; glycolysis. The low ATP yield of glucose in fermentation occurs because the glucose molecule is not completely broken down, or metabolized. Fermentation does not breakdown glucose to its full energy potential, but does provide a quick burst of necessary energy when oxygen cannot reach the cells fast enough  ALCOHOLIC FERMENTATION Alcoholic fermentation is an important economic resource. Bakers use the alcoholic fermentation of yeast to make breads. As yeasts break down the carbohydrates in dough, CO2 is produced and trapped in the dough. The bubbles of trapped CO2 cause the dough to rise and are visible as the small holes in baked bread. As the dough bakes, the yeasts die, and the alcohol evaporates. Alcoholic fermentation is also used to make wine, beer, and the ethanol that is added to gasoline to make gasohol.  Lactic Acid The partial breakdown of glucose in muscle cells results in lactic acid. If the blood cells cannot remove lactic acid build up quickly enough from the muscle cells it causes muscle fatigue – Lactate is removed by the oxygen cells found in the blood – Have you ever been sore after playing a football game or from climbing stairs the day before? Check Point! Oxygen is ________ during anaerobic respiration __________, _____, and ___________ are products of anaerobic respiration Aerobic respiration produces ______ ATP molecules than anaerobic respiration