BMB 251 1st Edition Lecture 4 Outline of Last Lecture I. Four main building blocks of Lifea. Fatty Acidsb. Carbsc. Amino Acidsd. NucleotidesII. Proteasome III. MetabolismOutline of Current Lecture IV. Nonspontaneous reactionsV. Free Energy (∆ G)VI. Electron carrier moleculesVII. GlycolysisVIII. Citric acid cycleIX. Electron transport chain/Oxidative phosphoylationCurrent Lecture- Nonspontaneous reactions are driven by coupling them to spontaneous reactions though the use of activated energy transporters (ATP, NAD, NADP), making the overall reaction spontaneous o Photosynthesis: converts light energy into chemical energyo Cellular respiration: goes through glycolysis, citric acid cycle and finally oxidative phosphorylation (electron transport chain) in order to convert glucose (food energy) intoATP for cellular reactions- Cells need a continuous supply of molecules to obtain their raw materials and energy (need monomers)o Catabolic pathways break down molecules to generate these monomers and chemical energyo Anabolic pathways consume the monomers and energy to synthesize molecules that are needed by the cell- Each step within a chemical reaction within the cell requires a specific enzyme whose one and only job is to help with that specific step of a metabolic pathway-whether it be further breaking down or building up the molecule - Most of these reactions of a subunit monomer being converted into a macromolecule are usually carried out through condensation synthesis, where a water molecule is released; this is not a spontaneous reaction and requires an input of energy. Therefore, these macromolecules are then broken down into their subunits via hydrolysis, where water is added back in the molecule; this is an exergonic reaction, has a -∆ G, and is spontaneous/highly favorableThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- The ∆ G of a chemical reaction determines whether the reaction is spontaneous or not o -∆ G = spontaneous reaction that is favorable in the environmento +∆ G = nonspontaneous reaction that is unfavorable and requires an input of energyto occuro∆ G=0: reaction is at equilibrium, no net change- Activated carrier molecules involved that are involved in reaction coupling:o ATP: most important carrier; it is the most commonly used and most abundanto NAD+ and NADP+: used in context of redox reactions carrier molecules of electronso Acetyl-CoA: another carrier (but of chemical energy) throughout the cell**coupled reactions do not need carrier molecules because the reactions use each other’s energy**other reactions need carrier molecules to use their stored potential energy for initiating reactions- Reduction of carbon is energetically unfavorable; it is a nonspontaneous reaction, gaining electrons and doing “uphill work” which requires an input of energy. On the other hand, the oxidation of carbon, or loss of electrons as - energy, is spontaneous; the energy can also be taken out by burning methane.- Major metabolic pathways that yield energy carriers and building blocks in animal cells:o Glycolysis Starts in cytosol Begins by oxidizing the carbon in glucose A small number of ATP is made here (2 net gain, 4 total produced) and pyruvates, which move on to the citric acid cycle Anaerobic because no oxygen is used in this processo Citric acid cycle: Moves across and into the mitochondrial membrane There is no ATP generated here, but GTP (very similar) is created and used directly after being made o Oxidative phosphorylation (Electron transport chain) ETC is the aerobic part of cellular respiration where oxygen is made into water and ADP is made into ATP through oxidative phosphorylation Takes a ton of energy to complete this process, but net gain of ATP is very large so the cell makes a net gain of energy to go do more
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