Cellular Respiration Harvesting Chemical Energy adapted from K. Foglia and K. Riedell

1. Cellular RespirationHarvesting Chemical Energy (adapted from K. Foglia and K. Riedell)

2. Harvesting stored energy Energy is stored in organic molecules carbohydrates, fats, proteins Heterotrophs eat these food digest organic molecules to get� raw materials for synthesis fuels for controlled release energy step-by-step enzyme-controlled reactions We eat to take in the fuels to make ATP which will then be used to help us build biomolecules and grow and move and� live! heterotrophs = �fed by others� vs. autotrophs = �self-feeders�We eat to take in the fuels to make ATP which will then be used to help us build biomolecules and grow and move and� live! heterotrophs = �fed by others� vs. autotrophs = �self-feeders�

3. Where do we get the energy from? Work of life is done by energy coupling use exergonic (catabolic) reactions to fuel endergonic (anabolic) reactions

4. ATP (Adenosine TriPhosphate) the cell�s renewable and reusable energy modified nucleotide nucleotide = adenine + ribose + Pi ? AMP AMP + Pi ? ADP ADP + Pi ? ATP adding phosphates is endergonic Marvel at the efficiency of biological systems! Build once = re-use over and over again. Start with a nucleotide and add phosphates to it to make this high energy molecule that drives the work of life. Let�s look at this molecule closer. Think about putting that Pi on the adenosine-ribose ==> EXERGONIC or ENDERGONIC?Marvel at the efficiency of biological systems! Build once = re-use over and over again. Start with a nucleotide and add phosphates to it to make this high energy molecule that drives the work of life. Let�s look at this molecule closer. Think about putting that Pi on the adenosine-ribose ==> EXERGONIC or ENDERGONIC?

5. LE 8-9

6. ATP / ADP cycle

7. LE 8-11

8. How does ATP transfer energy? ATP ? ADP releases energy (7.3 kcal/mole) Fuel other reactions Phosphorylation released Pi can transfer to other molecules destabilizing the other molecules enzyme that phosphorylates = �kinase� How does ATP transfer energy? By phosphorylating Think of the 3rd Pi as the bad boyfriend ATP tries to dump off on someone else = phosphorylating How does phosphorylating provide energy? Pi is very electronegative. Got lots of OXYGEN!! OXYGEN is very electronegative. Steals e�s from other atoms in the molecule it is bonded to. As e�s fall to electronegative atom, they release energy. Makes the other molecule �unhappy� = unstable. Starts looking for a better partner to bond to. Pi is again the bad boyfriend you want to dump. You�ve got to find someone else to give him away to. You give him away and then bond with someone new that makes you happier (monomers get together). Eventually the bad boyfriend gets dumped and goes off alone into the cytoplasm as a free agent = free Pi.How does ATP transfer energy? By phosphorylating Think of the 3rd Pi as the bad boyfriend ATP tries to dump off on someone else = phosphorylating How does phosphorylating provide energy? Pi is very electronegative. Got lots of OXYGEN!! OXYGEN is very electronegative. Steals e�s from other atoms in the molecule it is bonded to. As e�s fall to electronegative atom, they release energy. Makes the other molecule �unhappy� = unstable. Starts looking for a better partner to bond to. Pi is again the bad boyfriend you want to dump. You�ve got to find someone else to give him away to. You give him away and then bond with someone new that makes you happier (monomers get together). Eventually the bad boyfriend gets dumped and goes off alone into the cytoplasm as a free agent = free Pi.

9. Harvesting stored energy Ex: catabolism of glucose to produce ATP Movement of hydrogen atoms from glucose to waterMovement of hydrogen atoms from glucose to water

10. How do we harvest energy from fuels? Digest large molecules into smaller ones break bonds & move electrons from one molecule to another as electrons move they �carry energy� with them that energy is stored in another bond, released as heat or harvested to make ATP � They are called oxidation reactions because it reflects the fact that in biological systems oxygen, which attracts electrons strongly, is the most common electron acceptor. � Oxidation & reduction reactions always occur together therefore they are referred to as �redox reactions�. ��As electrons move from one atom to another they move farther away from the nucleus of the atom and therefore are at a higher potential energy state. The reduced form of a molecule has a higher level of energy than the oxidized form of a molecule. � The ability to store energy in molecules by transferring electrons to them is called reducing power, and is a basic property of living systems. � They are called oxidation reactions because it reflects the fact that in biological systems oxygen, which attracts electrons strongly, is the most common electron acceptor. � Oxidation & reduction reactions always occur together therefore they are referred to as �redox reactions�. ��As electrons move from one atom to another they move farther away from the nucleus of the atom and therefore are at a higher potential energy state. The reduced form of a molecule has a higher level of energy than the oxidized form of a molecule. � The ability to store energy in molecules by transferring electrons to them is called reducing power, and is a basic property of living systems.

11. How do we move electrons in biology? Moving electrons in living systems electrons cannot move alone in cells electrons move as part of H atom move H means move electrons Energy is transferred from one molecule to another via redox reactions. C6H12O6 has been oxidized fully == each of the carbons (C) has been cleaved off and all of the hydrogens (H) have been stripped off & transferred to oxygen (O) � the most electronegative atom in living systems. This converts O2 into H2O as it is reduced. The reduced form of a molecule has a higher energy state than the oxidized form. The ability of organisms to store energy in molecules by transferring electrons to them is referred to as reducing power. The reduced form of a molecule in a biological system is the molecule which has gained a H atom, hence NAD+ ? NADH once reduced. soon we will meet the electron carriers NAD & FADH = when they are reduced they now have energy stored in them that can be used to do work.Energy is transferred from one molecule to another via redox reactions. C6H12O6 has been oxidized fully == each of the carbons (C) has been cleaved off and all of the hydrogens (H) have been stripped off & transferred to oxygen (O) � the most electronegative atom in living systems. This converts O2 into H2O as it is reduced. The reduced form of a molecule has a higher energy state than the oxidized form. The ability of organisms to store energy in molecules by transferring electrons to them is referred to as reducing power. The reduced form of a molecule in a biological system is the molecule which has gained a H atom, hence NAD+ ? NADH once reduced. soon we will meet the electron carriers NAD & FADH = when they are reduced they now have energy stored in them that can be used to do work.

12. Oxidation & reduction Oxidation adding O removing H loss of electrons releases energy exergonic Reduction removing O adding H gain of electrons stores energy endergonic

13. Moving electrons in respiration Electron carriers move electrons by shuttling H atoms around NAD+ ? NADH (reduced) FAD+2 ? FADH2 (reduced) flavin adenine dinucleotide Nicotinamide adenine dinucleotide (NAD) � and its relative nicotinamide adenine dinucleotide phosphate (NADP) which you will meet in photosynthesis � are two of the most important coenzymes in the cell. In cells, most oxidations are accomplished by the removal of hydrogen atoms. Both of these coenzymes play crucial roles in this. Nicotinamide is also known as Vitamin B3 is believed to cause improvements in energy production due to its role as a precursor of NAD (nicotinamide adenosine dinucleotide), an important molecule involved in energy metabolism. Increasing nicotinamide concentrations increase the available NAD molecules that can take part in energy metabolism, thus increasing the amount of energy available in the cell. Vitamin B3 can be found in various meats, peanuts, and sunflower seeds. Nicotinamide is the biologically active form of niacin (also known as nicotinic acid). FAD is built from riboflavin � also known as Vitamin B2. Riboflavin is a water-soluble vitamin that is found naturally in organ meats (liver, kidney, and heart) and certain plants such as almonds, mushrooms, whole grain, soybeans, and green leafy vegetables. FAD is a coenzyme critical for the metabolism of carbohydrates, fats, and proteins into energy. Nicotinamide adenine dinucleotide (NAD) � and its relative nicotinamide adenine dinucleotide phosphate (NADP) which you will meet in photosynthesis � are two of the most important coenzymes in the cell. In cells, most oxidations are accomplished by the removal of hydrogen atoms. Both of these coenzymes play crucial roles in this. Nicotinamide is also known as Vitamin B3 is believed to cause improvements in energy production due to its role as a precursor of NAD (nicotinamide adenosine dinucleotide), an important molecule involved in energy metabolism. Increasing nicotinamide concentrations increase the available NAD molecules that can take part in energy metabolism, thus increasing the amount of energy available in the cell. Vitamin B3 can be found in various meats, peanuts, and sunflower seeds. Nicotinamide is the biologically active form of niacin (also known as nicotinic acid). FAD is built from riboflavin � also known as Vitamin B2. Riboflavin is a water-soluble vitamin that is found naturally in organ meats (liver, kidney, and heart) and certain plants such as almonds, mushrooms, whole grain, soybeans, and green leafy vegetables. FAD is a coenzyme critical for the metabolism of carbohydrates, fats, and proteins into energy.

14. Overview of cellular respiration 4 metabolic stages Anaerobic respiration 1. Glycolysis respiration without O2 in cytosol Aerobic respiration respiration using O2 in mitochondria Prestep 2a) Pyruvate oxidation 2. Krebs cycle 3. Electron transport chain