Slide 1 / 165 Respiration & Photosynthesis Slide 2 / 165 Energy and Life Usually, energy flows into ecosystems as light from the sun and leaves as heat. Photosynthesis uses the energy in sunlight to generate oxygen and glucose; while trapping carbon. Cellular respiration uses that glucose to generate ATP, which supplies useable energy for cells while releasing carbon and absorbing oxygen. Cells use ATP to generate. The overall effect is for solar energy to be transformed to energy that is used by life; and then finally heat. Much of that heat is then radiated away from Earth as infrared radiation. Slide 3 / 165 Energy and Life O O O C Solar N Fe Energy O HEAT Abiotic Chemicals (CO2, O2, N, minerals) HEAT HEAT Producers decomposers (plants) (bacteria, fungi) HEAT consumers (herbivores, carnivores) HEAT
Slide 4 / 165 The Production of ATP Catabolic Pathways Recall that catabolism is that aspect of metabolism involved in breaking down molecules to release energy. Cellular respiration is a catabolic pathway that consumes oxygen and organic molecules and yields ATP. Carbohydrates, fats, and proteins can all fuel cellular respiration. We'll look first at the simplest case, the breakdown of the sugar - glucose. Slide 5 / 165 The Production of ATP Catabolic Pathways The breakdown of organic molecules is exergonic , it releases energy. Catabolic pathways yield energy by oxidizing organic fuels. This is the balanced chemical reaction, when O 2 is available , for the combustion of glucose to provide energy to cells: C 6 H 12 O 6 + 6O 2 ⇒ 6CO 2 + 6H 2 O + ATP Slide 6 / 165 Combustion Reactions The shuttle boosters use the rapid combustion of fuel to power 4.4 billion pounds away from Earth. While the chemical process of cellular respiration is similar to this powerful reaction, cells must use a much more carefully-controlled process to get useable energy from the combustion of glucose.
Slide 7 / 165 Cellular Respiration There are two types of cellular respiration: · Anaerobic - which occurs without the use of oxygen · Aerobic - which requires the use of oxygen Both forms share the same first step: Glycolysis So let's talk about that first, then we can discuss the two types of respiration that follow from that first stage But before doing that we have to learn about two molecules that are essential to respiration Slide 8 / 165 NAD + and FAD The molecules NAD + and FAD are used to store, and later release, energy during respiration; they are key to respiration. Each molecules has two forms, each form stores a different amount of energy. So moving between those two forms either stores chemical potential energy or releases it. Here are the reactions: NAD + + 2H + + 2e - + Energy NADH + H + FAD + 2H + + 2e - + Energy FADH 2 The double arrows indicate that each reaction is reversible, they can proceed in either direction. When the reaction goes to the right, energy is stored. When it goes to the left, energy is released Slide 9 / 165 NAD + and FAD NAD + + 2H + + 2e - + Energy NADH + H + FAD + 2H + + 2e - + Energy FADH 2 The amount of energy that is useable when the reaction goes to the left, depends on the availability of O 2 . Without the presence of O 2 , the energy stored in NADH and FADH 2 cannot be used to make ATP. If O 2 is present , · 1 NADH stores enough energy to create about 3 ATPs · 1 FADH 2 stores enough energy to make about 2 ATPs
Slide 10 / 165 1 Anaerobic processes _____. A require the use of oxygen B do not require the use of oxygen C require the use of hydrogen D do not require the use of hydrogen Slide 11 / 165 2 Aerobic processes _____. A require the use of oxygen B do not require the use of oxygen C require the use of hydrogen D do not require the use of hydrogen Slide 12 / 165 NADH is converted to NAD + . During this process, _____. 3 A energy is released B energy is stored C no energy is stored or released
Slide 13 / 165 NAD + is converted to NADH. During this process, _____. 4 A energy is released B energy is stored C no energy is released or stored Slide 14 / 165 5 FAD is converted to FADH 2 . During this process, _____. A energy is released B energy is stored C no energy is released or stored Slide 15 / 165 6 FADH 2 is converted to FAD. During this process, _____. A energy is released B energy is stored C no energy is released or stored
Slide 16 / 165 Reduction and Oxidation NAD + + 2H + + 2e - + Energy NADH + H + FAD + 2H + + 2e - + Energy FADH 2 When we go from left to right we are adding electrons to a molecule. That is called reducing the molecule, or the process of reduction . Going from right to left, we are taking electrons from a molecule. That is called oxidizing the molecule, or the process of oxidation . Slide 17 / 165 Oxidation The reason for the term oxidation is that this is the effect that oxygen usually has: it takes electrons from a molecule, oxidizing the molecule The rusting of iron is an example of oxidation: oxygen is taking electrons from the metal, oxidizing it. 4 Fe + 3 O2 → 2 Fe2O3 Slide 18 / 165 Reduction and Oxydation LEO says GER Since it doesn't seem L osing right that adding E lectrons is electrons is called "reduction"; here's a O xidation way to remember these two terms. G aining E lectrons is R eduction
Slide 19 / 165 7 When a molecule is oxidized, electrons are removed from it. True False Slide 20 / 165 8 When a molecule is reduced, electrons are removed from it. True False Slide 21 / 165 Glycolysis This is the first stage of both anaerobic and aerobic respiration. It involves the breakdown of glucose , a 6 carbon sugar, into 2 molecules of pyruvate , a 3 carbon sugar. C 6 H 12 O 6 Glycolysis means the (Glucose) splitting of glucose 2 NAD + 2 ATP Gycolysis 2 NADH 4 ATP 2 C 3 H 4 O 3 (Pyruvate)
Slide 22 / 165 Glycolysis This is the first stage of both anaerobic and aerobic respiration. It involves the breakdown of glucose, a 6 carbon sugar, into 2 molecules of pyruvate, a 3 carbon sugar. Some ATP is needed C 6 H 12 O 6 to start the process, (Glucose) 2 NAD + 2 ATP but the net result is : Gycolysis 4 ATP 2 NADH 2 C 3 H 4 O 3 (Pyruvate) Slide 23 / 165 Glycolysis This is the first stage of both anaerobic and aerobic respiration. It involves the breakdown of glucose, a 6 carbon sugar, into 2 molecules of pyruvate, a 3 carbon sugar. C 6 H 12 O 6 Some ATP is needed to (Glucose) start the process, but the 2 NAD + 2 ATP net result is : Gycolysis a net of 2 ATPs are formed along with 2 4 ATP 2 NADH NADHs and the 2 pryuvates. 2 C 3 H 4 O 3 (Pyruvate) note: 2 ATP go into the reaction, 4 come out of the reaction - which gives the NET of 2 Slide 24 / 165 Fermentation Without O 2 , the energy stored in NADH 2 and pyruvate can't be used. The net energy gain of anaerobic respiration is just 2 ATPs. (Remember 2 were invested and 4 were produced, netting 2) However, the Pyruvate still needs to be cleared from the cell, and the NADH converted back to NAD+ to begin another cycle. The process of doing this is called fermentation .
Slide 25 / 165 9 The process of glylcolyis requires oxygen. True False Slide 26 / 165 Fermentation Fermentation breaks down the products of glycolysis so that glycolysis can be repeated with another glucose molecule. 2 C 3 H 4 O 3 (Pyruvate) 2 NADH Fermentation 2 NAD + OR Lactic Acid Ethanol Fermentation Fermentation 2 Lactic Acid CO 2 & 2 Ethanol Slide 27 / 165 Fermentation Fermentation breaks down the products of glycolysis so that glycolysis can be repeated with another glucose molecule. 1 glucose molecule had yielded 2 C 3 H 4 O 3 (Pyruvate) 2 ATPs, 2 Pyruvates and 2 2 NADH NADHs. That is the input to the Fermentation fermentation stage of anaerobic respiration. 2 NAD + OR Lactic Acid Ethanol Fermentation Fermentation 2 Lactic Acid CO 2 & 2 Ethanol
Slide 28 / 165 Fermentation Fermentation breaks down the products of glycolysis so that glycolysis can be repeated with another glucose molecule. 2 C 3 H 4 O 3 (Pyruvate) 1 glucose molecule had yielded 2 NADH 2 ATPs, 2 Pyruvates and 2 NADHs. That is the input to the Fermentation fermentation stage of anaerobic 2 NAD + respiration. OR Lactic Acid Ethanol Fermentation Fermentation The pyruvates and NADHs are fermented into 2 NAD + and 2 Lactic Acid either Lactic Acid or CO 2 & 2 Ethanol Slide 29 / 165 Fermentation Fermentation breaks down the products of glycolysis so that glycolysis can be repeated with another glucose molecule. 2 C 3 H 4 O 3 (Pyruvate) 1 glucose molecule had yielded 2 NADH 2 ATPs, 2 Pyruvates and 2 NADHs. That is the input to the Fermentation fermentation stage of anaerobic 2 NAD + respiration. OR Lactic Acid Ethanol Fermentation Fermentation The pyruvates and NADHs are fermented into 2 NAD + and 2 Lactic Acid either Lactic Acid or CO 2 & Ethanol. CO 2 & 2 Ethanol Slide 30 / 165 Anaerobic Respiration The result of the combined steps of glycolysis and fermentation is: · The input is 1 Glucose + 2 ATP molecules · The output is 4 ATP molecules (for a net gain of 2 ATP's) In addition, · Lactic Acid fermentation results in lactic acid · Ethanol fermentation results in ethanol and CO 2
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