E2P1 Cell Metabolism PPT - student PDF

Cellular Metabolism and Metabolic Pathways E2P1 Lecture Material for Exam 2  Terminology Catabolism – break down of large molecules o Anabolism – building large molecules o Substrate = reactant = beginning Product = ending  Structure of ATP Molecule A...

Cellular Metabolism and Metabolic Pathways E2P1 Lecture Material for Exam 2  Terminology Catabolism – break down of large molecules o Anabolism – building large molecules o Substrate = reactant = beginning Product = ending  Structure of ATP Molecule Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions.  Terminology 2 Oxidation – loss of electron – Reduction – gain of electron – Redox reaction - transfer of electron o Facilitated by high energy enzymes NADH and FADH2 Oxidative phosphorylation – conversion of NADH and FADH2 into ATP  Figure 24.4 Cellular Respiration Cellular respiration oxidizes glucose molecules through glycolysis, the Krebs cycle, and oxidative phosphorylation to produce ATP.  Glycolysis Catabolizes Carbohydrates Figure 3.41 *Do NOT memorize structures* Glycolysis Location: Cytosol Glucose (6C) ➞ 10 reactions ➞ 2 pyruvates (3C) – Note: pyruvic acid = pyruvate  Glycolysis Catabolizes Campbell Essential Biology with Physiology 4th Ed. Fig 6.7 Carbohydrates Glycolysis Location: Cytosol Glucose (6C) ➞ 10 reactions ➞ 2 pyruvates (3C) – Note: pyruvic acid = pyruvate Substrate Level Phosphorylation Produces ATP Directly Campbell Biology 9th Ed. Figure 9.7 Substrate-level phosphorylation Phosphate transferred directly from substrate to ADP to form ATP Mass Action Determines Pyruvate Fate Sprinters Marathoners aerobic anaerobic Anaerobic (low O2) Aerobic (high O2) – Fermentation – Kreb’s, Electron Transport (cytosol) (mitochondria)  Anaerobic Glycolysis Relies on Regeneration of NAD+ Anaerobic Glycolysis Regenerates NAD+ so reactions can persist Small, but ATP yield No O2 requirement The energy stored in (but still occurs in lactate is still used by presence of O2) the body  Anaerobic Glycolysis Relies on Regeneration of NAD+ Anaerobic Glycolysis 2 pyruvate + 2 NADH 2 lactate + 2 NAD+  Glycolysis Overview During the energy-consuming phase of glycolysis, two ATPs are consumed, transferring two phosphates to the glucose molecule. The glucose molecule then splits into two three-carbon compounds, each containing a phosphate. During the second phase, an additional phosphate is added to each of the three-carbon compounds. The energy for this endergonic reaction is provided by the removal (oxidation) of two electrons from each three-carbon compound. During the energy-releasing phase, the phosphates are removed from both three-carbon compounds and used to produce four ATP molecules. Anaerobic Glycolysis Summary (One Glucose) Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect Anaerob 2 4 0 0 0 4 2 0 ic ATP used: # of ATP broken down (input) glycolys is ATP direct: # ATP via substrate level phosphorylation NADH net: # NADH produced - # NADH used FADH2 net: # FADH2 produced - # FADH2 used ATP indirect: # ATP via oxidative phosphorylation (3 x #NADH) + (2 x #FADH2) via electron transport chain ATP total: ATP direct + ATP indirect ATP net: ATP total – ATP used CO2 net: CO2 produced Mass Action Determines Pyruvate Fate Sprinters Marathoners aerobic anaerobic Campbell Biology 9th Ed. Figure 9.18 Anaerobic (low O2) Aerobic (high O2) – Fermentation – Kreb’s, Electron Transport (cytosol) (mitochondria)  Under Aerobic Conditions Pyruvate Enters the Mitochondria Aerobic carbohydrate metabolism: 1. Glycolysis 2. Pyruvate activation 3. Kreb’s Cycle 4. Electron Transport Campbell Essential Biology with Physiology 4 th Ed. Ch Chain (ETC)  Under Aerobic Conditions Pyruvate Enters the Mitochondria Aerobic carbohydrateGlycolysis (aerobic conditions metabolism: 1. Glycolysis 2. Pyruvate activation 3. Kreb’s Cycle 4. Electron Transport Chain (ETC) Campbell Essential Biology with Physiology 4th Ed. Fig Electrons on Cytoplasmic Carriers Must Be “Shuttled” Into the Mitochondria FADH2 NADH Silverthorn 5th Ed *NADH* Cytoplasmic NADH has varied energy equivalents – Depends on active vs. passive transport  Electrons Must Enter Mitochondria Heart/Liver: Mitochondrial shuttles: Heart/Liver: Malate-aspartate shuttle – no energy loss – 3 ATP/NADH Skeletal Muscle: Skeletal Muscle: Glycerol-phosphate shuttle – energy loss – 2 ATP/NADH Under Aerobic Conditions Pyruvate Enters the Mitochondria Aerobic carbohydrate metabolism: 1. Glycolysis 2. Pyruvate activation 3. Kreb’s Cycle Campbell Biology 9th Ed. Figure 9.10 4. Electron Transport Chain (ETC) Under Aerobic Conditions Pyruvate Enters the Mitochondria Aerobic carbohydrate metabolism: 1. Glycolysis 2. Pyruvate activation 3. Kreb’s Cycle 4. Electron Transport Chain (ETC) *Do NOT memorize structures*  Electron Carriers Link Glycolysis and the Kreb’s Cycle to Oxidative Phosphorylation Campbell Biology 9th Ed. Figure 9.6 The electron transport chain produces ATP from high energy electrons via oxidative phosphorylation The Electron Transport Chain Produces ATP by Oxidative Phosphorylation Electrons transferred to electron transport chain – Energy released during transfer pumps H+ into FADH2 NADH intermembrane space Chemiosmosis: H+ gradient used to make ATP (ATP synthase) Silverthorn 5th Ed. – NADH = 3 ATP – FADH2 = 2 ATP Oxygen is required as the ultimate electron acceptor: ‘oxidative phosphorylation’ Complete Oxidation of Glucose  Complete Oxidation of Glucose Glycolysis (Aerobic): Heart/Liver Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect glycolys 2 4 2 0 6 10 8 0 is ATP used: # of ATP broken down (input) ATP direct: # ATP via substrate level phosphorylation NADH net: # NADH produced - # NADH used FADH2 net: # FADH2 produced - # FADH2 used ATP indirect: # ATP via oxidative phosphorylation ((3 x #NADH) + (2 x #FADH2) via electron transport chain) ATP total: ATP direct + ATP indirect ATP net: ATP total – ATP used CO2 net: CO2 produced Complete Oxidation of Glucose Glycolysis (Aerobic): Skeletal Muscle Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect glycolys 2 4 0 *Cytosolic 2* 4 NADH 8 converted to6 FADH2 0 is ATP used: # of ATP broken down (input) ATP direct: # ATP via substrate level phosphorylation NADH net: # NADH produced - # NADH used FADH2 net: # FADH2 produced - # FADH2 used ATP indirect: # ATP via oxidative phosphorylation ((3 x #NADH) + (2 x #FADH2) via electron transport chain) ATP total: ATP direct + ATP indirect ATP net: ATP total – ATP used CO2 net: CO2 produced Complete Oxidation of Glucose Pyruvate Activation Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect activati 0 0 2 0 6 6 6 2 on ATP used: # of ATP broken down (input) ATP direct: # ATP via substrate level phosphorylation NADH net: # NADH produced - # NADH used FADH2 net: # FADH2 produced - # FADH2 used ATP indirect: # ATP via oxidative phosphorylation ((3 x #NADH) + (2 x #FADH2) via electron transport chain) ATP total: ATP direct + ATP indirect ATP net: ATP total – ATP used CO2 net: CO2 produced Complete Oxidation of Glucose Kreb’s Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect Kreb’s 0 2 6 2 22 24 24 4 ATP used: # of ATP broken down (input) ATP direct: # ATP via substrate level phosphorylation NADH net: # NADH produced - # NADH used FADH2 net: # FADH2 produced - # FADH2 used ATP indirect: # ATP via oxidative phosphorylation ((3 x #NADH) + (2 x #FADH2) via electron transport chain) ATP total: ATP direct + ATP indirect ATP net: ATP total – ATP used CO2 net: CO2 produced Summary of Glucose Oxidation Heart/Liver Process ATP ATP NADH FADH ATP ATP ATP CO2 used direct net 2 indire total net net net ct glycolysi 2 4 2 0 6 10 8 0 s activatio 0 0 2 0 6 6 6 2 n 1.Kreb’s Glycolysis: 0 2 6 2 22 24 24 4 total 1glucose 2 +6 10 2pyruvate 2ATP ➞ 2 34 40 + 2NADH + 4ATP 38 6 2. Pyruvate Activation: 2pyruvate + 2NAD+ ➞ 2Acetyl CoA + 2CO2 + 2NADH 3. Kreb’s: 2Acetyl CoA + 6NAD++ 2FAD + 2ADP ➞ 4CO2 + 6NADH + Summary of Glucose Oxidation Skeletal Muscle Proces ATP ATP NAD FADH ATP ATP ATP CO2 s used direc H 2 indir total net net t net net ect glycolys 2 4 0 2* 4 8 6 0 is activati 0 0 2 0 6 6 6 2 on 1.Kreb’s Glycolysis: 0 2 6 *Cytosolic 2 NADH 22 converted 24 to FADH42 24 total 1glucose 2 + 62ATP ➞ 8 2pyruvate 4* 32+ 4ATP 38 + 2NADH 36 6 2. Pyruvate Activation: 2pyruvate + 2NAD+ ➞ 2Acetyl CoA + 2CO2 + 2NADH 3. Kreb’s: 2Acetyl CoA + 6NAD++ 2FAD + 2ADP ➞ 4CO2 + 6NADH +  Metabolic Timeline What happens after we eat? What happens between meals? What happens when we skip a meal?  Metabolic Timeline What happens after we eat? 0-4 hours; anabolic phase Pancreas releases insulin to get glucose into cells Liver: extra glucose→glycogen; AA→ketones Muscle: glucose→glycogen; AA repair tissue Adipose: store extra fats  Absorptive State During the absorptive state, the body digests food and absorbs the nutrients.  Metabolic Timeline What happens between meals? 4-16 hours; catabolic phase Initially rely on glycogen Liver: release glucose; ketones→ATP Muscle: release glucose; AA→ketones→ATP Adipose: release stored lipids  Postabsorptive State During the postabsorptive state, the body must rely on stored glycogen for energy.  Metabolic Timeline What happens when we skip a meal? 16 hours+; starvation Fat-burning Glycolysis stops in cells that can use other alternate sources Fatty acids and triglycerides are used to create ketones What Happens When There Is No Glucose? Glucose is the primary energy souce – Adequate levels must be maintained Sources of glucose: – Glycogen (primary) Glycogenolysis: Breakdown of glycogen Glycogenesis: Synthesis of glycogen – Gluconeogenesis Glucose from glycolytic intermediates (run glycolysis backwards) – Lactate – Glycolysis intermediates – Glucogenic amino acids – Glycerol from triglycerides (minor) Silverthorn 5th Ed. Figure 4.1 Protein Catabolism Produces Toxic Intermediates Protein Catabolism: 1. Proteolysis: polymer ➞ monomers – Enzyme: proteases – Polypeptide (protein) ➞ amino acids 2. Deamination – Amino Acid ➞ NH3 + organic (keto) acid – NH3 ➞ NH4+ (ammonium; toxic) – NH4+ ➞ urea (liver) ➞ excreted 3. Energy Production – Glycolysis and/or Kreb’s Glucogenic: glycolysis Ketogenic: Kreb’s – Oxidative phosphorylation Siverthorn 5th Ed. Fats Are the Most Efficient Energy Storage Molecule Lipids are calorically dense – 9kcal/g – Carbons are more reduced – Less weight of hydration 10,000kcals stored as fat – enough to run 100 miles (or sleep for months)  Important Metabolic Hormones Cortisol – – gluconeogenesis – break down fats and proteins to increase blood glucose Glucagon – – breaks down glycogen in liver to increase blood glucose Epinephrine – – stimulates gluconeogenesis Insulin – – helps cells take glucose from blood and store it as glycogen in liver – anabolic