An Organism’s Metabolism Matter and Energy

Chapter 6: An organism’s metabolism matter and energy ● Metabolism breaks down your food but also about building up. It is everything going on in your body, all your enzymes reaction, all the ATP being converted to ADP (and vice versa) is your metabolism. ● Metabolism is the totality of the organism’s chemical reaction. ● Emergent means bigger than some of its parts. Metabolism is a bigger thing than its reactions. Metabolism is an emergent property of life that arises from interactions between molecules within the cell. ● Balance of the anabolistic and catabolistic reactions in a biological system. ● Anabolic builds up, catabolic builds/breaks down. ● Anabolic pathways consume energy to build complex molecules from simpler ones. - Synthesis of amino acids is an example. ● Catabolic pathways releases energy by breaking down complex molecules - Cellular respiration is an example, it breaks down glucose and other organic fuels to carbon dioxide water. What is metabolism? a. A balance of anabolistic and catabolistic reactions in the body. b. the totality of an organism's chemical reactions. c. an emergent property of life that arises from interactions between molecules within the cell. d. all of these choices answer the question correctly. What is the currency of energy in biological systems? ● To make something you have to have the parts. The first thing in the process is the eating of food, breaking down said food such as a burger, everything you would get from that burger, it breaks the burger down into its components and gives you energy. ● So then what is this energy? What form does it take? ATP, the electrons. So it is electrons being carried by ATP ● What is the ultimate source of energy? Electrons. Not ATP, they are just the shuttle for the electrons. ● Now you have the parts, you can make something out of it. The parts/energy came from the burger, and it is being stored in ATP, now you have the ability to make a baby. ● Most things are multiple steps, called metabolic pathways. You have to get to D, but have to go through A, B, and C first. Each step is a separate reaction and ends with a product, where the product becomes the reactant for the next reactant. There is an enzyme that catalyzes each step. Metabolic pathways begin with a specific molecule and end with a product. Glycolysis ● This is the first set of reactions of cellular respiration called glycolysis. ● Starts with glucose, six carbon molecules, sugar, goes through a series of metabolic pathways, until it winds up being converted into two three carbon molecules called pyruvate. With every beginning glucose molecule, you end up with 2 pyruvates, start with six and end up with 2 sets of three carbons. ● Each one of these is glucose being converted into something, that thing being converted to something else, and so on. This is an example of a metabolic pathway, glycolysis. ● Reactions and products, each one has an enzyme that orchestrates it, most of the time it tells you what it does, such as phosphofructokinase means it phosphorylates something else. ● How does the ATP shuttle the electrons, what part is the energy? Phosphate is rich in electrons, and it gets added to something (kinase). ● Side product: not a reactant, it occurred because this happened and influenced the side product. It is not in the reaction but happens because of the reaction. - You can identify side products by tracking changes in energy carriers (like ATP, ADP, NADH) and released molecules (such as protons, Pi) that result from the transformation of the main reactants. ● At the beginning, ATP is used. At the end, ATP is created. We know this because the ATP went down by looking at the side products. The ATP phosporylated glucose, then it happens again, and again, so on. ● The reaction of glycolysis is catabolistic in the beginning, and anabolistic at the end as far as ATP is concerned. ● In each one, it winds up smaller than it started with so in total, it is a catabolistic reaction. Laws of Thermodynamics ● First Law of Thermodynamics - energy cannot be created or destroyed. ● Energy can only be converted from one form to another ● For example: sunlight energy >>>>> chemical energy ● Photosynthesis ● Second Law of Thermodynamics: disorder is more likely than order entropy: disorder in the universe ● The 2nd Law of Thermodynamics states that entropy is always increasing. Flow of Energy ● Most forms of energy can be converted to heat energy. ● Heat energy is measured in kilocalories. ● One calorie = the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere ● 1 kilocalorie (kcal) = 1000 calories Where does biological energy come from? ● Potential energy stored in chemical bonds can be transferred from one molecule to another ● Oxidation is the loss of electrons ● Reduction is the gain of electrons (because you get a negative, it is the gain of energy) ● Redox reactions are coupled to each other ● From the image below, molecule A is oxidized and B is reduced.