Chapter 6 Cellular Respiration Part 2 2024 PDF

CHAPTER 6 PART II THE PROCESS OF CELLULAR RESPIRATION CELLULAR RESPIRATION: Dr. Samhan HARVESTING CHEMICAL ENERGY 1  Respiration involves three stages: 1. Glycolysis: Oxidizing gl...

CHAPTER 6 PART II THE PROCESS OF CELLULAR RESPIRATION CELLULAR RESPIRATION: Dr. Samhan HARVESTING CHEMICAL ENERGY 1  Respiration involves three stages: 1. Glycolysis: Oxidizing glucose to pyruvate and produces about 5% of ATP in the cytoplasm 2. Krebs cycle: THE PROCESS Completes the oxidation of glucose and produces about 5% of ATP, in OF CELLULAR the mitochondrial matrix RESPIRATION 3. Electron transport chain: To synthesis ATP and produces about 90% of ATP, inner mitochondrial membrane Cellular respiration generates upto 38 ATP molecule for each sugar molecule it oxidizes CELLULAR RESPIRATION STAGES  Respiration occurs in three metabolic stages: glycolysis, the Krebs cycle, and the electron transport chain and oxidative phosphorylation Glycolysis: Occurs in the cytoplasm, breaks glucose into 2 STAGES OF molecules of pyruvate CELLULAR Citric Acid Cycle: Takes place in RESPIRATION the mitochondria, oxidizes acetyl- CoA to produce NADH, FADH2, and ATP Oxidative Phosphorylation: Involves the electron transport chain (ETC) and generating the majority of ATP  Glycolysis: The carbon backbone of glucose is broken down and partially oxidized during glycolysis A glucose molecule (6 carbons) GLYCOLYSIS is split into two molecules of pyruvate (3 carbons each) Two ATP are required, and 4 ATP are produced Net gain of 2 ATP in addition to 2 NADH CELLULAR RESPIRATION STAGES  Pyruvate is transported into the mitochondrial matrix Pre-Krebs cycle: Each pyruvate (3 carbons) is converted into CITRIC ACID acetyl-CoA (2 carbons) by losing one carbon as CO2 CYCLE (KREBS Produces 1 NADH & 1 CO2 per pyruvate CYCLE) For Each Acetyl-CoA: 2 CO2 (carbon dioxide) 3 NADH (electron carrier) 1 FADH2 (electron carrier) 1 ATP (produced by substrate-level phosphorylation)  Complete Oxidation: During the citric acid cycle, the COMPLETE carbon atoms of glucose are fully oxidized and released as CO2 OXIDATION Glucose is completely broken down OF GLUCOSE to CO2, and energy is stored in electron carriers (NADH and FADH2).  In the inner mitochondrial membrane cristae The energy in the electrons carried ELECTRON by NADH and FADH2 is used in the electron transport chain to power TRANSPORT ATP synthesis CHAIN (OXIDATIVE PHOSPHORYLATION)  Cytochrome proteins are essential for the process of oxidative phosphorylation ATP-synthase, in the cristae makes ATP Electrons from NADH or FADH2 ultimately pass to oxygen ELECTRON Chemiosmosis: TRANSPORT It is the oxidative phosphorylation that results in ATP production in the inner CHAIN membrane of mitochondria (OXIDATIVE PHOSPHORYLATION)  - Glycolysis occurs in the cytosol and breaks glucose into two pyruvates - Krebs Cycle takes place within the mitochondrial matrix and breaks a pyruvate into CO2 and SUMMARY OF produce some ATP and NADH CELLULAR RESPIRATION - Electron Transport Chain accepts e- from NADH and passes them from one protein molecule to another - At the end of the chain, e- combine with both H+ and O2 to form H2O and release energy  Glycolysis: 2 ATP Citric Acid Cycle: NET ATP YIELD 2 ATP FROM GLUCOSE Oxidative Phosphorylation: OXIDATION 26-28 ATP Total: 30-32 ATP per glucose molecule SUMMARY OF CELL RESPIRATION  Chemiosmosis: a process in which oxidative phosphorylation takes place at the end of the ETC to produce 90% of ATP via ATP-synthase ATP-synthase: an enzyme presents in the inner mitochondrial membrane and used in making ATP by using H+ DEFINITIONS NAD+: Nicotinamide adenine dinucleotide, which is a co-enzyme that helps electron transfer during redox reactions in cellular respiration FAD: Flavin adenine dinucleotide, which is an electron acceptor that helps electron transfer in cellular respiration. 10/5/2024 COURSE NAME AND NO. – ‫اسم ورقم المقرر‬ 15  Fermentation: Occurs without oxygen, relies only on glycolysis, producing 2 ATP and either lactic acid or ethanol FERMENTATION AND Anaerobic Respiration: ANAEROBIC Uses an electron transport chain RESPIRATION with a final electron acceptor other than oxygen (e.g., sulfate or nitrate), generating more ATP than fermentation but less than aerobic respiration  Pyruvate (from glycolysis) is converted into ethanol and CO2 in two steps: FATE OF Pyruvate is decarboxylated to form PYRUVATE IN acetaldehyde and releases CO2 ALCOHOL Acetaldehyde is reduced by NADH FERMENTATION to ethanol This occurs in yeast and some bacteria when oxygen is absent  Pyruvate is reduced directly by NADH to form lactate, regenerating NAD+ Occurs in muscle cells during FATE OF muscular exercise when oxygen is PYRUVATE IN limited (anerobic respiration), and in LACTIC ACID certain bacteria FERMENTATION No CO2 is produced Clinical Example: Lactic acid buildup can cause muscle fatigue and soreness  Alcohol Fermentation: Produces ethanol and CO2, occurs in yeast and some bacteria ALCOHOL AND Lactic Acid Fermentation: Produces LACTIC ACID lactate, occurs in muscle cells and FERMENTATION some bacteria. Both regenerate NAD+ to allow glycolysis to continue producing ATP in anaerobic conditions.  Fermentation: Produces only 2 ATP per glucose molecule through glycolysis ATP YIELD IN Much less efficient than cellular respiration, which yields 30-32 FERMENTATION ATP per glucose Key Concept: Fermentation is a short-term solution for energy needs when oxygen is unavailable  A. Fats - Have more energy per gram than carbohydrates or proteins (~2x as much) - Fatty acid chains are oxidized and FAT AND broken into smaller 2 carbon chains PROTEIN - The 2 carbon chains are converted BREAKDOWN into acetyl CoA to enter the Kreb’s cycle B. Proteins - Excess amino acids are converted by enzymes into intermediated of glycolysis and Krebs cycle REFERENCES THANK YOU