Unit 2 Lesson 1_ Intro to Metabolism + Glycolysis (2024) PDF

Intro to Metabolism Energy = the capacity to do work or to change things Needed for… Growth, Development Movement, Metabolism Reproduction…To live! 1st Law of Thermodynamics Energy cannot be created or destroyed, but it can be changed from one form to another Energy Transformations Met...

Intro to Metabolism Energy = the capacity to do work or to change things Needed for… Growth, Development Movement, Metabolism Reproduction…To live! 1st Law of Thermodynamics Energy cannot be created or destroyed, but it can be changed from one form to another Energy Transformations Metabolism: The sum total of the chemical reactions that occur in a call, usually to transform matter and energy In all cells of all organisms, two types of metabolic reactions occur: Anabolic Reactions = “building up” Catabolic Reactions = “breaking down” Exergonic Reactions vs. Endergonic Reactions (Catabolism) (Anabolism) Products store less energy than Products store more energy the reactants, and excess than the reactants, and energy energy is released. must be supplied for the reaction to proceed Most spontaneous reactions require an initial input of energy, such as a spark, to begin them. This activation energy destabilizes the existing chemical bonds, allowing new products to form. In biological reactions, the amount of activation energy required can be reduced by the use of a biological catalyst - an enzyme (maaaany enzymes involved in metabolism) Adenosine Triphosphate (ATP) Primary source of free energy in all living cells Energy released by catabolic reactions is captured in the molecule ATP and used to power reactions The bonds between the negative phosphate groups in ATP contain a large amount of energy. Energy Dynamics of ATP: Dephosphorylation/Hydrolysis The hydrolysis of ATP to ADP (adenosine diphosphate) and Pi (inorganic phosphate) is a highly exergonic reaction. When bonds between phosphate groups are broken, energy is released. ○ approx. 34 kJ Called dephosphorylation, or hydrolysis  Energy Dynamics of ATP Phosphorylation, or dehydration synthesis/ condensation Dephosphorylation, or hydrolysis Energy Dynamics of ATP: Phosphorylation Substrate-level phosphorylation can be catalyzed by an enzyme (happens during beginning stages of CR.) This requires 31 kJ of energy to make the bond. Energy Dynamics of ATP: Phosphorylation Oxidative phosphorylation can occur during the final stage of cellular respiration (the electron transport chain). Uses redox reactions and specialized structures to generate energy to form the bond in ATP. REDOX REACTIONS REDOX REACTIONS Redox reactions commonly occur in electron carriers in CR Electron carriers are compounds that “pick up” electrons from energy-rich compounds and “donate” them to low-energy compounds (making one compound oxidized, and another reduced) Cellular Respiration  Big Picture: Cellular Respiration Cellular respiration is a set of metabolic steps that take place in a cell to break down glucose (energy found in food) and produces ATP (useable chemical energy in the body). Without cellular respiration we would have no useable energy! Cellular Respiration is an Exergonic Reaction C6H12O6 (s) + 6O2(g) 🡪 6CO2(g) + 6H2O(l) + energy  Mitochondria Found in all aerobic eukaryotic cells. Self replicating with its own DNA. Outer membrane isolates the mitochondria from the other cell organelles. The first stages of cellular respiration occur in the cytoplasm outside of the mitochondria, however, the stages with the highest ATP production occur on the inside General Summary General Summary  Total Energy Production From One Glucose Molecule From Respiration In the end the total energy production from each glucose molecule is 36 ATP. 1) Glycolysis: 4-2 ATP = 2 ATP (+ 2 NADH) 2) Krebs: 1 ATP per G3P = 2 ATP (+6 NADH, 4 FADH2) 3) Electron Transport Chain: 8 NADH x 3 ATP = 24 ATP 4 FADH2 x 2 ATP = 8 ATP 36 ATP Some sources say different amounts, but this is what we are sticking with in our course!!!  Practice Read p.90-93 (Cellular Respiration: The Big Picture) Answer p.93 #1-4 **Optional - Can also read Chapter 1.3 (p.58-67) for extra information on Intro to Metabolism/Energy Transformation/ATP Cellular Respiration: Step 1 - Glycolysis  Step 1: Glycolysis -Occurs in the cytoplasm. -Glucose (6C) is broken down into 2 pyruvate molecules (3C) which are needed for the next steps of CR -Very little energy is released → 2 ATP -Oxygen is not required for this reaction. (anaerobic.) Glycolysis has 10 reactions: - The first five reactions convert a molecule of glucose into https://www.youtube.com/watch?v=8Kn6BVGqKd8 two molecules of glyceraldehyde-3-phosphate (G3P). - The second five reactions convert each G3P into pyruvate. - Every step is catalyzed by a specific enzyme - we are not going to be concerned about the specific enzymes as much, however you do need to know all of the full names of the products for each reaction  ATP used ATP used NADH made NADH made ATP made ATP made ATP made ATP made Glycolysis (Reactions 1-3) 1: Phosphorylation of glucose by ATP to become glucose 6-phosphate (G6P) 2: Rearrangement of G6P into fructose 6-phosphate (F6P) *isomers 3: Phosphorylation of F6P by a second ATP to become fructose 1,6-bisphosphate(F1,6-BP) These reactions have used 2 ATP, produced 0. Glycolysis (Reactions 4-5) 4-5: F1,6-BP is split into two 3-carbon molecules: one glyceraldehyde 3-phosphate (G3P) and DHAP (which then gets converted into another G3P molecule - isomers) There are now 2 G3P molecules, each of which will proceed in the following reactions (6-10). DHAP → G3P Glycolysis (Reactions 6-7) *happening to 2 G3Ps 6: G3P is converted into 1,3-bisphosphoglycerate (BPG) through oxidation (loss of H) and phosphorylation. In this process, NAD+ is reduced into NADH through the addition of hydrogens. 7: One of the high-energy phosphates is lost from BPG, resulting in the phosphorylation of an ADP molecule into ATP, and 3-phosphoglycerate (3PG) formed. 2 NADH and 2 ATP have been formed (1 per G3P) Glycolysis (Reactions 8-10) *happening to 2 G3Ps 8: 3PG is rearranged into 2-phosphoglycerate (2PG) (isomers) 9: Removal of water from 3PG yields a phosphoenolpyruvate (PEP) molecule, still with a high energy phosphate bond 10: Removal of high-energy phosphate, phosphorylating ADP into ATP and leaving a pyruvate molecule 2 more ATP have been made through these last reactions (1 per G3P)  The Net Result from Glycolysis is …. 1 glucose molecule makes 2 pyruvate, 2 ATP and 2 NADH Substrate-level Phosphorylation Example: Reaction 1: Phosphorylation of Glucose by ATP Substrate-level Phosphorylation Example: Reaction 9 - Phosphorylation of ADP by PEP Coupled Redox Reaction Example: Reaction 6 - G3P to BPG NAD+ is reduced (gain of an H+ and 2 e-) (loss of hydrogen)  Glycolysis Videos https://www.youtube.com/watch?v=hDq1rhUkV-g&t=1s video has great detail, but remember you do not need to know the enzymes https://www.youtube.com/watch?v=SXScylUJ0y4 good basic summary of names - however, we do not use ‘PGAL’ we use ‘glyceraldehyde-3-phosphate’ (G3P)  Practice Read p.94-99 (review of phosphorylation, redox reactions and glycolysis) Answer p. 115 #1-6