1	CELLULAR RESPIRATION USING ATP
2	RESPIRATION VS CELLULAR RESPIRATION Respiration is ‘breathing’ – the exchange of gases in the lungs. Cellular respiration is the aerobic harvesting of energy from food molecules that occurs in all cells. The lungs take up O₂ into the bloodstream and it is carried to all body cells. The mitochondria in each cell use the O₂ to generate ATP from food (glucose) which will be used by the cell for energy to run all the processes occurring in the cell.
3	CELLULAR RESPIRATION The primary function of cellular respiration is to produce energy molecules – ATP. C₆H₁₂O₆ + 6O₂ à 6CO₂ + 6H₂0 + ATP This process breaks the bonds in glucose releasing the energy holding the atoms together and transferring the energy to the bonds holding the PO₄ ions to the ATP
4	CELLULAR RESPIRATION The energy available to a cell is contained in the specific arrangement of electrons in the chemical bonds that hold together an organic molecule like glucose. Glucose loses hydrogen atoms as it is converted to CO₂ And O₂ gains hydrogen atoms in being converted to H₂O.
5	CELLULAR RESPIRATION These hydrogen transfers represent electron transfers. Because of O₂ high electronegativity, it pulls the hydrogen electrons away from the glucose and bonds with it to form H₂O.
6	CELLULAR RESPIRATION The processes are continuous but can be divided into 3 stages: 1. Glycolysis begins the break down of glucose into 2 pyruvic acid molecules and occurs in the cytoplasm. 2. Krebs cycle takes place in the mitochondria completes the breakdown of pyruvic acid to CO₂ 3.The electron transport chain moves the electrons thru carrier molecules to form ATP.
7	GLYCOLYSIS This stage starts with glucose and ends with pyruvic acid. The intermediate compounds that are formed cause 2 ATP to form. See Pg 97 for complete listing of intermediates.
8	CELLULAR RESPIRATION
9	KREBS CYCLE The citric acid cycle is also known as the Krebs cycle after Sir Hans Adolph Krebs (1900-1981), who proposed the key elements of this pathway in 1937 and was awarded the Nobel Prize in Medicine for its discovery in 1953. The citric acid cycle takes place within the mitochondria in eukaryotes, and within the cytoplasm in prokaryotes.
10	KREBS CYCLE Pyruvic acid diffuses through the cytoplasm into the mitochondria, where 3 things happen immediately. 1. pyruvic acid is oxidized while a molecule of NAD⁺ is reduced to NADH 2. a carbon atom is remove and released in CO₂ 3. a compound called coenzyme A joins with the 2-carbon fragment remaining from pyruvic acid to form a molecule called acetyl coenzyme A.
11	KREBS CYCLE The 2-carbon acetyl part of acetyl Co A is what actually participated is the Krebs cycle. The CoA splits off and is recycled. The steps of the Krebs cycle strips the acetyl CoA of electrons forming 2 CO₂for each acetyl. At the end of the Krebs cycle, 4 ATP, 10 NADH and 2 FADH₂ have been formed. See page 99 for detail of the Krebs cycle.
12	ELECTRON TRANSPORT CHAIN This is the final stage of cellular respiration where more ATP is synthesized. The spatial arrangement of membrane proteins make it possible for the mitochondrion to use chemical energy to create an H⁺ gradient and then use the energy stored in that gradient to drive ATP synthesis.
13	ELECTRON TRANSPORT CHAIN The folds (cristae) of the membrane increases the surface area providing space for many copies of the ETC many ATP synthase complexes. This allows a mitochondrion to produce many ATP simultaneously. See pg 100 for the ETC.
14	Cellular Respiration Yields Theoretically, the maximum yield from a complete breakdown of one glucose molecule is 38 ATP. This is about 40% of the potential energy stored in glucose.
15	ANAEROBIC RESPIRATION This type of respiration is performed by organisms without mitochondria, such as bacteria and yeasts. These organisms survive without oxygen on the 2 ATP produced by glycolysis.
16	ALCOHOLIC FERMENTATION This is a form of respiration used by yeasts. They convert the pyruvic acid to CO₂ and ethanol by employing several enzymes. The ethanol is a poison to the yeasts so they excrete it.
17	LACTIC ACID FERMENTATION This process is used by many kinds of cells when O₂is not available. Lactic acid is produced when NADH from glycolysis is oxidized. 2 ATP are formed but no CO₂.
18	FOOD AS FUEL Since we don’t consume glucose in its pure form to feed the cellular respiration process, we must convert the foods we eat into glucose or pyruvic acid. Most polysaccharides are hydrolyzed in our digestive system to glucose and enter glycolysis. Most fats are converted to glycerol and fatty acids which are then converted to G3P, pyruvic acid or Acetyl CoA.
19	FOOD AS FUEL Proteins are digested to their component amino acids and used to make more proteins or may be converted to pyruvic acid or one of the Krebs cycle’s organic acids.
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