Chapter 7 Cellular Respiration PDF

Okay, here is the converted document in a structured markdown format. # NUR ATIKAH KHADIJAH BINTI MOHD ALI # CHAPTER 7 ## CELLULAR RESPIRATION ### Learning Outcomes ### Students should be able to: **(a)** describe the structure and metabolism of ATP. **(b)** explain the glycolysis, pyruvate oxida...

Okay, here is the converted document in a structured markdown format. # NUR ATIKAH KHADIJAH BINTI MOHD ALI # CHAPTER 7 ## CELLULAR RESPIRATION ### Learning Outcomes ### Students should be able to: **(a)** describe the structure and metabolism of ATP. **(b)** explain the glycolysis, pyruvate oxidation, and citric acid cycle. **(c)** explain the electron transport chain and chemiosmosis. **(d)** explain the terms substrate level and oxidative phosphorylation. **(e)** calculate the total amount of ATP released at the various stages of cellular respiration. **(f)** describe the pathways involved in fermentation. (LAB 5 RESPIRATION) **(g)** compare and contrast aerobic respiration and fermentation. (LAB 5 RESPIRATION) **(h)** describe carbohydrate, fat and protein metabolism as well as relate them to glycolysis and citric acid cycle. **(i)** apply the knowledge gained in this section in new situations or to solve related problems. ## CHAPTER 7 ### CELLULAR RESPIRATION $In: O_2, Out: CO_2$ gas exchange. **7.1 THE ATP MOLECULE** * ATP (adenosine triphosphate)= Nucleotide with unstable phosphate bonds that cell hydrolyzes for energy to drive endergonic reactions. * Consists of adenine base, ribose sugar and chain of three phosphate groups. * When terminal phosphate bond is hydrolyzed, a phosphate group is removed producing ADP (adenosine diphosphate). $ATP + H_2O \rightarrow ADP + P_i + energy$ (exergonic process) * general equation: (more energy) (exergonic) $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_20 +(release energy)$ *(a) The structure of ATP* *(b) The hydrolysis of ATP* *How ATP performs work* *Exergonic hydrolysis of ATP coupled with endergonic processes - phosphate group transferred to another molecule. *Phosphate transfer is enzymatically controlled. *Molecule receiving phosphate (phosphorylate/activated intermediate) becomes reactive. *The regeneration of ATP* * ATP is continually regenerated by cell. * Rapid Process: $10^7$ molecules used and regenerated/sec/cell. * Reaction: endergonic. $ADP + P_i \rightarrow ATP$ $∆G = + 31 kj/mol (+7.3 kcal/mol)$ * Energy to drive the endergonic regeneration of ATP comes from an (exergonic process of cellular respiration.) ### 2 ways regeneration of ATP: a) **Substrate level phosphorylation** - Synthesis of ATP by direct transfer of (a phosphate group from an organic substrate to ADP by an enzyme) b) **Oxidative phosphorylation** * The production of ATP using energy derived from the redox reactions of an electron chain (ETC.) * Produces almost 90% of ATP generated by respiration. * ETC is a collection of molecules embedded in the inner membrane of mitochondria in eukaryote. **7.2 AEROBIC RESPIRATION oxidation of glucose** *Preview of cellular respiration* (See Figure 10.5 Campbell 12th edition, page 241) Stages of respiration: i. Glycolysis ii. Pyruvate oxidation iii. Citric Acid cycle/Krebs cycle iv. Oxidative phosphorylation ### 7.1 Glycolysis Occurs in the cytoplasm in the absence or presence of oxygen Glycolysis means "sugar splitting". Glucose splits into 2 molecules of glyceraldehyde 3-phosphate (G3P) Sugars oxidized and rearranged to form two molecules of pyruvate Two phases of glycolysis: (use energy) $Glucose \rightarrow 2G3P 2 \rightarrow Pyruvate$ ### 1. Energy investment phase * Cell invests ATP * phosphorylating glucose * Requires 2 ATP per glucose. * In a series of chemical reactions, 1 molecule of glucose converted to 2 molecules of glyceraldehyde 3-phosphate (G3P) ### 2. Energy payoff phase * In a series of chemical reactions 2 molecules of glyceraldehyde 3-phosphate (G3P) is converted to pyruvate * Produced 4ATP and 2NADH per glucose * ATP produced by substrate-level phosphorylation * $NAD^+ $reduced to NADH by electrons released by oxidation of glucose. $NAD^+ + 2H^+ +2 \overline{e} \rightarrow NADH + H^+$ * NADH carries 2 electro Net yield from glycolysis = 2 ATP and 2 NADH per glucose. No $CO_2$ produced during glycolysis. Glycolysis occurs in presence/absence of $O_2$ Overall reaction showing all reactants and products resulting from glycolysis. * [ ] 1x Glucose * [ ] 2 x ATP * [ ] 2 x ADP * [ ] 2 x Glyceraldehyde 3-phosphate * [ ] 2 x NAD+ * [ ] 2 x NADH * [ ] 4 x ADP * [ ] 4 x ATP * [ ] 2 x Pyruvate **2.2 Pyruvate oxidation** (See Figure 10.9, Pearson 12th ed, page 243) 3/4 of original energy, in glucose, is still present in the 2 molecules of pyruvate. If $O_2$ is present, pyruvate in eukaryote cells enters mitochondrion where oxidation to $CO_2$ is completed. after pyruvate enters via active transport, it is converted to Involve multienzyme complex that catalyzes three reactions: *remaining the *2 ATP left *(1) carboxyl group removed as $CO_2$, decarboxytation *(2) remaining 2C fragment oxidized to acetate *(3) An enzyme transfers 2 electrons to NAD+ to form NADH *(4) Acetate combines with coenzyme A ,very reactive acetyl CoA Acetyl CoA enters citric acid cycle for further oxidation #### 7.2.3 The Citric Acid Cycle (See Figure 10.11, Pearson 12th ed, page 245) Also known as Krebs cycle, tricarboxylic acid cycle. Occurs in in mitochondria matrix. Acetyl group of acetyl CoA combines with OAA, forming citrate. Citrate regenerated back to OAA ***For each acetyl CoA produces: .*** * $2CO_2$ * $3NADH$ * $1 FAD_2$ * $1 ATP$ by substrate level phosphorylation #### The Citric Acid Cycle : **Q:** What will happen to FADH2 and NADH produced in citric acid cycle? most of the energy of the original glucose molecule is in the dorm of high energy electrons in NADH and FADH2. Their energy will be used to synthesized additional atp via oxidative phosphorylation. #### 7.2.4 Oxidative phosphorylation (Electron Transport Chain and Chemiosmosis) (See Figure 10.12 and 10.13, Pearson 12th, page 246-247) * During oxidative phosphorylation chemiosmosis, couples electron transport to synthesise ATP. * 4 out of 32 ATP are produced by substrate level phosphorylation. * Glycolysis 2 ATP. * Citric acid cycle - 2 ATP. *Electron Transport Chain* another protein molecule* . * Involve protein complex I through IV embeded in cristae * Each protein complex consist series of electrons carrier NADH delivers two electrons and two protons (H+) to the first protein complex (I). * The electron carriers will reduce and oxidize as it accepts and transfers electron (redox) * as an election passes through an election carrier, energy is released from the electron. * The released energy, is used to pump Proton (H+) at complex protein complex I, III, and IV from matrix into intermembrane spaces After passing, through three protein complexes elections, combine with one oxygen atom and two H+ to form water. $2H^+ + 2e + \frac{1}{2}O_2 \rightarrow H_2O$ FADH2 delivered election to Protein complex I Election to Protein complex III and IV. Only complex III and IV pump protons into intermembrane space. The last election carries passes it's election to oxygen ( final election acceptor). $2H^+ + 2e + \frac{1}{2}O_2 \rightarrow H_2O$ * Election carried by FADH2, produces less energy for ATP synthesis. #### Chemiosmosis: Energy-Coupling Mechanism * The transport of H+ across the membrane produces a concentration gradient. * Higher concentration of H+ in intermembrane space compared to H+ concentration in the metrix of mitochondria. The H+ gradients the results, is a proton-motive force. * The gradient is used to make ATP. * Cristae membrane impermeable to H+ accepted there are ATP synthesies, at protons pass through it, passage, drives the phosphorylation of ADP to form ATP, Chemiosmosis. * 1 NADH generous proton motive force for the synthesise of 2.5 ATP. * 1 FADH2 generous proton motive force for the synthesise of 1.5 ATP *Electron transport chain* ##### 7.3 Calculations of Total ATP Production by Cellular Respiration *(refer to Figure 10.16, Campbell 10th Edition, page 251)* aerobic respiration of one gulose molecule could generate: i. 28 / 26 ATP from oxidative phosphorylation ii 4 ATP from subsrate Level phosphorylation. a complete oxidation ox one molecule it glucose via aerobic respiration produces a total yeild of 32 / 30 ATP. ConversionsNADH * In cytoplasm produces 1.5 and 2.5 ATP BY oxidative phosphorylation, depending on shuttle system used to transport electrons from cytosol, into mitochondrial: * if electrons are passed to FAD e.g brain cells muscle cells - 1.5ATP * if electrons are passed to NAD+ eng Liver cells $Heart cells = 2.5 *ATPSHOW, the calculation of ATP for one and molecule, glucoses **total yeilds** | Pathway | Substrate - Level Phosphorylation | Oxidative Phosphorylation | | :-------------- | :---------------------------------- | :------------------------------ | | Glycolysis | 2 | 28/ 26 (Brain) 1.523 (liver) 2.5 | | Pyruvate | | 2 NADH = 5 ATP | | Krebs cycle | 2 | 6 NADH = 15ATP | | 2 FADH2 = 3 ATP | | | | Total | 4 ATP | 26/28 ATP | *Maximun per glucose and 2 ATP* *## 7.4 FREMENTATION (en the Lab)* Refer to Figure 10.16 Compele, 12th Edition, page 250 #### 7.5- Methanalies of Fat Type of metabolism **7.5.1 Catabonism, depends on exercise** * carbohydrades, fats and protiens, can and be USED for fuel for cellur respiration ###### Carbohydrates: * Polysaccharides ( starch glycogen hydrolized to glucose, monomers that inter glycolysis. * Hexose sugars galactose fructose - modified to and Undergo, Glycosis * protein: Proteins digested to and dividual Amon acids, Group removed