Biology Midterm 2 Notes - Energy
Energy!
!
General! • cells require a constant supply of energy to generate and maintain biological order that keeps them alive! • they get this from chemical bond energy in food molecules, aka fuel for cells! • plants get sugars from CO2 through photosynthesis, where animals gain it from eating other organisms ! • cells that form the organism harvest useful energy from chemical bond energy locked in sugars, which are oxidized into CO2 and H2O ! • this energy is stored as harvest energy (release large amounts of energy when hydrolyzed in activated carrier molecules such as ATP and NADPH)!
!
The Breakdown and Utilization of Sugars and Fats! • living cells use enzymes to carry out the oxidation of sugars in a tightly controlled series of rxns! • animal cells make ATP in two ways! 1. Enzyme catalyzed rxns are directly coupled to the energetically unfavourable rxn ADP + Pi -> ATP! Most ATP synthesis occur in the mitochondria which involves activated carrier molecules which will in return drive ATP production! • Food molecules are broken down in three stages! 1. Digestion: the enzymatic break down of food molecules, which is on the outside of cells in a specialized organelle within cells called Lysosomes. Digestive enzymes reduce large polymeric units into monomeric subunits (proteins into amino acids, polysaccharides into sugars, fats into fatty acids and glycerol)! 2. Glycolysis: chain of reactions, where each molecule of glucose is converted into two smaller molecules of pyruvate. Two types of activated carrier molecules are produced: ATP and NADPH. Pyruvate transported from cytosol into mitochondrion’s large, matrix. Giant enzyme complex converts each pyruvate molecule into CO2 and Acetyl CoA (another carrier enzyme). ! 3. TCA cycle and Oxidative Phosphorylation (in Mitochondria): the acetyl group in acetyl CoA is ripped apart and transferred to a molecule called oxaloacetate to form citrate which then leads to the citric acid cycle. CO2 is oxidized and large amounts of NADH is generated. This is then transported to along a series of enzymes within the mitochondrial inner membrane called the electron transport chain. This process includes the release of energy which leads
into producing ATP and consuming molecular Oxygen. Most of the cells ATP is harnessed at this step. ! **Nearly half of energy that could be derived from oxidation of glucose or fatty acids to H2O and CO2 is captured and used to drive the energetically unfavourable reaction ADP + Pi -> ATP **!
!
• Glycolysis is a Central ATP-Producing Pathway! - glycolysis produces ATP without the involvement of Oxygen! - occurs in the cytosol of most cells and is the only anaerobic phase of cellular respiration! - during glycolysis, glucose molecule (6 Carbon atoms) is cleaved into two molecules of pyruvate (which contains 3 Carbon atoms)!
!
After Glycolysis the pyruvate produced must either undergo the rest of cellular respiration or fermentation. Fermentation allows ATP to be produced in the absence of Oxygen. ! ! ! 1. Alcoholic Fermentation: occurs in yeast and in plant cells if oxygen isn't ! ! ! available ! !
! ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! !
! ! !
2. Lactic Acid Fermentation: occurs in many bacterial cells in some animal ! cells as well (muscle cells). Lactic acid produced can be converted back into pyruvate when oxygen is available!
BPG= Bisphosphoglyceride Glycolysis is a process that involves 10 separate rxns each producing a different intermediate sugar and each catalyzed by a different enzyme! ! ATP Glucose!
1. phosphorylation by ATP produces molecule ! !an activated ! ! !
2. Rearranged to unstable isomer
!
ADP
! Glucose 6 Phosphate! ! ! Fructose 6 Phosphate! !
ATP
!
! Fructose 1,6 Diphosphate !
ADP
3. 2nd Phosphorylation
! !
4. Molecule splits into ! ! ! 2 G3P from DHAP
DHAP!!
!
!
!
G3P!
! !
! ! ! ! ! ! ! ! 6. Oxidation of G3P produces NADH ! ! ! ! (phosphorylation of !both G3P) ! ! ! ! ! !
2G3P!
2NAD+ 2NADH
! 2P
2BPG!
2ADP
!
! ! ! ! ! ! ! !8. Removal of water gives PEP !high energy bond ! ! ! ! ! !
! ! ! !
5. DHAP rearranged to form 2G3P
2ATP
2 3PG!
7. Substrate level phosphorylation, BPG gives up phosphate to form ATP
H 2O
2PEP!
2ADP 2ATP
!
!
!
!
Glycolysis Overview:! Input - glucose! ! 2ATP! ! 2 Phosphate Groups! ! 2 NAD+! ! 4 ADP!
2 Pyruvate!
!
9. 2nd Substrate level phosphorylation
Output - 2 Pyruvate! ! 2H2O! ! 4 ATP! ! 2 NADH (~3 ATP)! ! 2 ADP! !
**NET GAIN OF 5 ATP**!
! !
Glycolysis continued: ! • no molecular oxygen is involved in glycolysis! • oxidation occurs! • electrons are removed from some of the carbons derived from glucose by NAD+ producing NADH! • the synthesis of ATP in glycolysis is known as Substrate-level phosphorylation because it occurs by the transfer of a phosphate group directly from a substrate molecule (sugar intermediate) to ADP, remainder energy is stored in electrons within NADH!
!
Electron Carriers! • NAD+ : nicotinamide adenine dinucleotide (vitamin B3)! • FAD: flavin adenine dinucleotide (vitamin B2)! • NADP+: nicotinamide adenine dinucleotide phosphate!
! NAD(P)H! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
NAD+ + H+ +2e- NADH
Three ways to make ATP! 1. Substrate Level Phosphorylation! • generates a a few ATP during glycolysis!
! ! !
! 2. Oxidative Phosphorylation (aerobic Respiration)! • electrons harvest are used to pump H+ ions across a membrane (proton pump)! • protons can back up and run ATP synthase !
! ! !
! !
3. Photophosphorylation! • occurs in chloroplasts! • cyclic and non cyclic phosphorylation !
!
Reduction-Oxidation (redox) reactions! • electrons, most chemical potential energy in cells, they are mobile, LEO or GER is also potential! !
! !
Reduction and Oxidation of the Coenzyme NAD+! • when high energy molecules bind to enyzme, it gives up H+ (becomes oxidized, less energy)! • NAD+ accepts H+ and becomes reduced (more energy)! • the reduced energy carriers carry electrons to electron transport chain!
!
Transition Reaction/ Pyruvate Oxidation:! • occurs in mitochondrial matrix! • if oxygen is only available! • connects glycolysis to krebs cycle! • pyruvate is oxidized and one molecule of CO2 is lost!
! !
What is coenzyme A?! • derived from pantothenic acid, nucleotide derivative! • an organophosphate! • a thiol!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
Krebs Cycle = TCA (tricarboxylic acid) cycle = Citric Acid Cycle! ! Acetyl CoA (2C)
Citrate (6C) Oxaloacetate (4C)
Isocitrate (6C)
NAD
Malate (4C)
CO2 (into atmosphere)
NAD+
H2O
NAD+
NADH
Alpha-Ketoglutarate (5C) CO2 (into atmosphere) NAD+
Fumerate (4C) Succinyl CoA (4C)
Succinate (4C) FADH
!
!
! !
FAD
**2x per glucose (twice)**!
lol
! ! = oxidative phosphorylation! ! !
**Need two turns for each molecule of glucose !**!
! ! ! Memorizing Aid: ! ! Can I Kick Some Soccer Balls From My Office! !
ADP + P
ATP
NADH
What does the TCA cycle accomplish?! • 2 carbon acyl units are fully oxidized to yield (2 molecules of CO2, 2C of blucose fully oxidized)! • 1 GTP = 1 ATP (substrate level phosphorylation)! • molecule required to restart the cycle is regenerated !
!
What happens if there is no Oxygen?! • there is no oxygen to accept final e- in ETC! • oxidative phosphorylation backs up ! • all NADH and FADH2 are in reduced form! • TCA cycle shuts down!
!
Acetyl-CoA as a Central Hub in Energy Metabolism! • Where do acyl groups come from to form acetyl CoA? ! -oxidation of pyruvate, breakdown of proteins and breakdown of fats and other lipids! • what can the cell do with acetyl CoA? ! -Oxidize and make ATP, fat synthesis! • Which process predominates? ! -Lots of ATP in cell (oxidative pathway inhibited-> cell makes fatty acids -> stores fat)! -Low ATP -> oxidative pathway predominates !
! ! ! !
Other Fuel Molecules:! • Proteins: become amino acids, deaminated and fed into TCA cycle! • Fats: become fatty acids + glycerol and broken down into 2C units which are then broken down into acetyl CoA (B-oxidation)!
! **for ATP production, cells first use CHOs, then fats, and finally proteins**! !
Glycolysis and TCA cycle (KEY POINTS)! • since a pathway is made possible by enzyme catalyzed reactions: we can regulate the FLUX through the pathway by regulating the activity of the enzymes in the pathway and glycolysis and TCA are regulated at several points by substrate availability and feedback (product inhibition)!
!
Regulation of Metabolic Pathways!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
• During feedback inhibition (negative inhibition and positive inhibition), the concentration of the end product dictate the activity of the enzyme! • when an enzyme in a pathway is inhibited by a product of that pathway it is known as feedback inhibition!
Key points in Glycolysis and TCA: !
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
- NADH, ATP, Acetyl CoA
- ATP
- ATP, NADH +ADP
- NADH, ATP, succinyl CoA
Regulation of Glycolysis! • phosphofructokinase is an allosteric enzyme in glycolysis and high levels of ATP inhibit this enzyme ! • phosphofructokinase has two binding sites for ATP! - ATP binds to regulatory site! - enzyme changes shape -> reduced activity!
! ! ! ! !
Active site
Regulatory/ allosteric site
! ! !
! !
! fructose-1,6! bisphosphate ! at active site ! ! What we want to do:! ! !C H O +' 6O2' ! 6 12 6'
ADP at active site
6CO2' +' 6H2O'+'ATP'
What we have so far:!
C6H12O6'
!
6CO2' +''a'few'ATP'+'lots'of'NADH'
What we do is… ! • Take the NADH and FADH generated from the krebs cycle and unleash them into the matrix side where they enter the inner mitochrondrial membrane! • This is generally known as a redox reaction - Electron Transport Chain (ETC) because it transfers e- to series of membrane associated proteins that shuttle electrons !
! ! ! ! ! ! ! ! !
Electron Transport Chain (ETC)! • series of e- embedded in inner mitochondrial membrane! • NADH delivers e- to top chain, O2 catches at the bottom! • O2 joins with H to form water! • results- for every 2 e- one O2 molecule is reduced to two molecules of water! • the ULTIMATE electron acceptor in ETC is Oxygen!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
It generates ATP…! • via a process known as chemiosmosis ! - harnessing electrochemical gradient of H+ ions across a membrane to make ATP! - Theory: most ATP in respiring cells come from electrochemical gradient across inner mitochondrial membrane, generated using energy from NADH, FADH2, derived from breakdown of fuel molecules! - they also have the ability to re-establish equilibrium and electrical charge (neutrality = allows pyruvate to move in and out which alleviates potential energy resulting in smaller pH)!
! ! ! ! ! ! ! ! ! ! ! !
ATP Synthase! ! membrane potential (DeltaV) and pH gradient (DeltapH) which is used by ATP Synthase to generate ATP
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! ! ! ! ! !
channel allows proton to enter into ATPase
bind to rotor subunit, which turns protons and moves in circular motion
catalytic subunit
! !
SUMMARY ! OF ! EVERYTHING!
contains all binding factors
Product yields from Glucose Oxidation!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
-1.5 ATP per FADH2! -2.5 ATP per NADH!
!
Oxidative Phosphorylation Summary! • NADH and FADH2 are passed along a series of proteins in the inner mitochondria membrane (ETC)! • ultimately the destination of the electrons is to reduce O2 to H2O! • the return of protons to the matrix drives the formation of ATP and consumes O2! • if there is no oxygen present there will be NO OXYGEN to accept final e- transfer, oxidative phosphorylation backs up and beings to process all NADH and FADH2 in reduced form and eventually the TCA cycle shuts down! **if no oxygen is present, that means ATP source shuts down **!
! Only organisms with low energy needs can cope !! !
Anaerobic lifestyle, it must find another way to UNLOAD NADH, this is through fermentation, this is very inefficient! Aerobic has 2 ATP molecules per glucose molecules whereas, there are 30 produced in Cellular Respiration!
! ! ! ! !
Aerobic Respiration!
Fermentation
Aerobic Respiration!
Fermentation
SIMILARITIES!
make energy by breaking down glucose, both release energy
make energy by breaking down glucose, both release energy
DIFFERENCES
oxygen is present
no oxygen present
! ! ! !
Pathway!
Substrate Level Phosphorylation
Oxidative Phosphorylation
Total ATP
Glycolysis
2ATP! !
2NADH = 3ATP
5 ATP
Transition!
———————!
2NADH = 5 ATP!
5 ATP
Krebs!
2 ATP!
6 NADH = 15 ATP! 2 FADH2= 3 ATP! 2 GTP = 2 ATP
20 ATP
TOTAL
4 ATP
28 ATP
30 ATP
! ! ! ! Energy Generation in Chloroplasts! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! Independent and Dependant Reactions!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!
!
!
PHOTOSYNTHESIS!
Capture Light Enerrgy! ! Light Reactions! Dark Reaction! ! ! ! ! ! (Photophosphorylation)!! ! ! Produce Carbohydrates! ! ! ! ! ! ! Reduced Energized! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! G3P! ! ! ! Water Split (photolysis)! ! ! Energized ! Must G3P Glucose, ! starch and used to ! ! ! Oxygen is Realized! ! ! ! ETC! cellulose regenerate ! ! ! ! ! ! ! ! ! ! ! ! ! ! Chemiosmosis! RuBP
! !
!
!
!
!
!
!
!
Produce ATP
!
General! • cells require a constant supply of energy to generate and maintain biological order that keeps them alive! • they get this from chemical bond energy in food molecules, aka fuel for cells! • plants get sugars from CO2 through photosynthesis, where animals gain it from eating other organisms ! • cells that form the organism harvest useful energy from chemical bond energy locked in sugars, which are oxidized into CO2 and H2O ! • this energy is stored as harvest energy (release large amounts of energy when hydrolyzed in activated carrier molecules such as ATP and NADPH)!
!
The Breakdown and Utilization of Sugars and Fats! • living cells use enzymes to carry out the oxidation of sugars in a tightly controlled series of rxns! • animal cells make ATP in two ways! 1. Enzyme catalyzed rxns are directly coupled to the energetically unfavourable rxn ADP + Pi -> ATP! Most ATP synthesis occur in the mitochondria which involves activated carrier molecules which will in return drive ATP production! • Food molecules are broken down in three stages! 1. Digestion: the enzymatic break down of food molecules, which is on the outside of cells in a specialized organelle within cells called Lysosomes. Digestive enzymes reduce large polymeric units into monomeric subunits (proteins into amino acids, polysaccharides into sugars, fats into fatty acids and glycerol)! 2. Glycolysis: chain of reactions, where each molecule of glucose is converted into two smaller molecules of pyruvate. Two types of activated carrier molecules are produced: ATP and NADPH. Pyruvate transported from cytosol into mitochondrion’s large, matrix. Giant enzyme complex converts each pyruvate molecule into CO2 and Acetyl CoA (another carrier enzyme). ! 3. TCA cycle and Oxidative Phosphorylation (in Mitochondria): the acetyl group in acetyl CoA is ripped apart and transferred to a molecule called oxaloacetate to form citrate which then leads to the citric acid cycle. CO2 is oxidized and large amounts of NADH is generated. This is then transported to along a series of enzymes within the mitochondrial inner membrane called the electron transport chain. This process includes the release of energy which leads
into producing ATP and consuming molecular Oxygen. Most of the cells ATP is harnessed at this step. ! **Nearly half of energy that could be derived from oxidation of glucose or fatty acids to H2O and CO2 is captured and used to drive the energetically unfavourable reaction ADP + Pi -> ATP **!
!
• Glycolysis is a Central ATP-Producing Pathway! - glycolysis produces ATP without the involvement of Oxygen! - occurs in the cytosol of most cells and is the only anaerobic phase of cellular respiration! - during glycolysis, glucose molecule (6 Carbon atoms) is cleaved into two molecules of pyruvate (which contains 3 Carbon atoms)!
!
After Glycolysis the pyruvate produced must either undergo the rest of cellular respiration or fermentation. Fermentation allows ATP to be produced in the absence of Oxygen. ! ! ! 1. Alcoholic Fermentation: occurs in yeast and in plant cells if oxygen isn't ! ! ! available ! !
! ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! !
! ! !
2. Lactic Acid Fermentation: occurs in many bacterial cells in some animal ! cells as well (muscle cells). Lactic acid produced can be converted back into pyruvate when oxygen is available!
BPG= Bisphosphoglyceride Glycolysis is a process that involves 10 separate rxns each producing a different intermediate sugar and each catalyzed by a different enzyme! ! ATP Glucose!
1. phosphorylation by ATP produces molecule ! !an activated ! ! !
2. Rearranged to unstable isomer
!
ADP
! Glucose 6 Phosphate! ! ! Fructose 6 Phosphate! !
ATP
!
! Fructose 1,6 Diphosphate !
ADP
3. 2nd Phosphorylation
! !
4. Molecule splits into ! ! ! 2 G3P from DHAP
DHAP!!
!
!
!
G3P!
! !
! ! ! ! ! ! ! ! 6. Oxidation of G3P produces NADH ! ! ! ! (phosphorylation of !both G3P) ! ! ! ! ! !
2G3P!
2NAD+ 2NADH
! 2P
2BPG!
2ADP
!
! ! ! ! ! ! ! !8. Removal of water gives PEP !high energy bond ! ! ! ! ! !
! ! ! !
5. DHAP rearranged to form 2G3P
2ATP
2 3PG!
7. Substrate level phosphorylation, BPG gives up phosphate to form ATP
H 2O
2PEP!
2ADP 2ATP
!
!
!
!
Glycolysis Overview:! Input - glucose! ! 2ATP! ! 2 Phosphate Groups! ! 2 NAD+! ! 4 ADP!
2 Pyruvate!
!
9. 2nd Substrate level phosphorylation
Output - 2 Pyruvate! ! 2H2O! ! 4 ATP! ! 2 NADH (~3 ATP)! ! 2 ADP! !
**NET GAIN OF 5 ATP**!
! !
Glycolysis continued: ! • no molecular oxygen is involved in glycolysis! • oxidation occurs! • electrons are removed from some of the carbons derived from glucose by NAD+ producing NADH! • the synthesis of ATP in glycolysis is known as Substrate-level phosphorylation because it occurs by the transfer of a phosphate group directly from a substrate molecule (sugar intermediate) to ADP, remainder energy is stored in electrons within NADH!
!
Electron Carriers! • NAD+ : nicotinamide adenine dinucleotide (vitamin B3)! • FAD: flavin adenine dinucleotide (vitamin B2)! • NADP+: nicotinamide adenine dinucleotide phosphate!
! NAD(P)H! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
NAD+ + H+ +2e- NADH
Three ways to make ATP! 1. Substrate Level Phosphorylation! • generates a a few ATP during glycolysis!
! ! !
! 2. Oxidative Phosphorylation (aerobic Respiration)! • electrons harvest are used to pump H+ ions across a membrane (proton pump)! • protons can back up and run ATP synthase !
! ! !
! !
3. Photophosphorylation! • occurs in chloroplasts! • cyclic and non cyclic phosphorylation !
!
Reduction-Oxidation (redox) reactions! • electrons, most chemical potential energy in cells, they are mobile, LEO or GER is also potential! !
! !
Reduction and Oxidation of the Coenzyme NAD+! • when high energy molecules bind to enyzme, it gives up H+ (becomes oxidized, less energy)! • NAD+ accepts H+ and becomes reduced (more energy)! • the reduced energy carriers carry electrons to electron transport chain!
!
Transition Reaction/ Pyruvate Oxidation:! • occurs in mitochondrial matrix! • if oxygen is only available! • connects glycolysis to krebs cycle! • pyruvate is oxidized and one molecule of CO2 is lost!
! !
What is coenzyme A?! • derived from pantothenic acid, nucleotide derivative! • an organophosphate! • a thiol!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
Krebs Cycle = TCA (tricarboxylic acid) cycle = Citric Acid Cycle! ! Acetyl CoA (2C)
Citrate (6C) Oxaloacetate (4C)
Isocitrate (6C)
NAD
Malate (4C)
CO2 (into atmosphere)
NAD+
H2O
NAD+
NADH
Alpha-Ketoglutarate (5C) CO2 (into atmosphere) NAD+
Fumerate (4C) Succinyl CoA (4C)
Succinate (4C) FADH
!
!
! !
FAD
**2x per glucose (twice)**!
lol
! ! = oxidative phosphorylation! ! !
**Need two turns for each molecule of glucose !**!
! ! ! Memorizing Aid: ! ! Can I Kick Some Soccer Balls From My Office! !
ADP + P
ATP
NADH
What does the TCA cycle accomplish?! • 2 carbon acyl units are fully oxidized to yield (2 molecules of CO2, 2C of blucose fully oxidized)! • 1 GTP = 1 ATP (substrate level phosphorylation)! • molecule required to restart the cycle is regenerated !
!
What happens if there is no Oxygen?! • there is no oxygen to accept final e- in ETC! • oxidative phosphorylation backs up ! • all NADH and FADH2 are in reduced form! • TCA cycle shuts down!
!
Acetyl-CoA as a Central Hub in Energy Metabolism! • Where do acyl groups come from to form acetyl CoA? ! -oxidation of pyruvate, breakdown of proteins and breakdown of fats and other lipids! • what can the cell do with acetyl CoA? ! -Oxidize and make ATP, fat synthesis! • Which process predominates? ! -Lots of ATP in cell (oxidative pathway inhibited-> cell makes fatty acids -> stores fat)! -Low ATP -> oxidative pathway predominates !
! ! ! !
Other Fuel Molecules:! • Proteins: become amino acids, deaminated and fed into TCA cycle! • Fats: become fatty acids + glycerol and broken down into 2C units which are then broken down into acetyl CoA (B-oxidation)!
! **for ATP production, cells first use CHOs, then fats, and finally proteins**! !
Glycolysis and TCA cycle (KEY POINTS)! • since a pathway is made possible by enzyme catalyzed reactions: we can regulate the FLUX through the pathway by regulating the activity of the enzymes in the pathway and glycolysis and TCA are regulated at several points by substrate availability and feedback (product inhibition)!
!
Regulation of Metabolic Pathways!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
• During feedback inhibition (negative inhibition and positive inhibition), the concentration of the end product dictate the activity of the enzyme! • when an enzyme in a pathway is inhibited by a product of that pathway it is known as feedback inhibition!
Key points in Glycolysis and TCA: !
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
- NADH, ATP, Acetyl CoA
- ATP
- ATP, NADH +ADP
- NADH, ATP, succinyl CoA
Regulation of Glycolysis! • phosphofructokinase is an allosteric enzyme in glycolysis and high levels of ATP inhibit this enzyme ! • phosphofructokinase has two binding sites for ATP! - ATP binds to regulatory site! - enzyme changes shape -> reduced activity!
! ! ! ! !
Active site
Regulatory/ allosteric site
! ! !
! !
! fructose-1,6! bisphosphate ! at active site ! ! What we want to do:! ! !C H O +' 6O2' ! 6 12 6'
ADP at active site
6CO2' +' 6H2O'+'ATP'
What we have so far:!
C6H12O6'
!
6CO2' +''a'few'ATP'+'lots'of'NADH'
What we do is… ! • Take the NADH and FADH generated from the krebs cycle and unleash them into the matrix side where they enter the inner mitochrondrial membrane! • This is generally known as a redox reaction - Electron Transport Chain (ETC) because it transfers e- to series of membrane associated proteins that shuttle electrons !
! ! ! ! ! ! ! ! !
Electron Transport Chain (ETC)! • series of e- embedded in inner mitochondrial membrane! • NADH delivers e- to top chain, O2 catches at the bottom! • O2 joins with H to form water! • results- for every 2 e- one O2 molecule is reduced to two molecules of water! • the ULTIMATE electron acceptor in ETC is Oxygen!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
It generates ATP…! • via a process known as chemiosmosis ! - harnessing electrochemical gradient of H+ ions across a membrane to make ATP! - Theory: most ATP in respiring cells come from electrochemical gradient across inner mitochondrial membrane, generated using energy from NADH, FADH2, derived from breakdown of fuel molecules! - they also have the ability to re-establish equilibrium and electrical charge (neutrality = allows pyruvate to move in and out which alleviates potential energy resulting in smaller pH)!
! ! ! ! ! ! ! ! ! ! ! !
ATP Synthase! ! membrane potential (DeltaV) and pH gradient (DeltapH) which is used by ATP Synthase to generate ATP
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! ! ! ! ! !
channel allows proton to enter into ATPase
bind to rotor subunit, which turns protons and moves in circular motion
catalytic subunit
! !
SUMMARY ! OF ! EVERYTHING!
contains all binding factors
Product yields from Glucose Oxidation!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
-1.5 ATP per FADH2! -2.5 ATP per NADH!
!
Oxidative Phosphorylation Summary! • NADH and FADH2 are passed along a series of proteins in the inner mitochondria membrane (ETC)! • ultimately the destination of the electrons is to reduce O2 to H2O! • the return of protons to the matrix drives the formation of ATP and consumes O2! • if there is no oxygen present there will be NO OXYGEN to accept final e- transfer, oxidative phosphorylation backs up and beings to process all NADH and FADH2 in reduced form and eventually the TCA cycle shuts down! **if no oxygen is present, that means ATP source shuts down **!
! Only organisms with low energy needs can cope !! !
Anaerobic lifestyle, it must find another way to UNLOAD NADH, this is through fermentation, this is very inefficient! Aerobic has 2 ATP molecules per glucose molecules whereas, there are 30 produced in Cellular Respiration!
! ! ! ! !
Aerobic Respiration!
Fermentation
Aerobic Respiration!
Fermentation
SIMILARITIES!
make energy by breaking down glucose, both release energy
make energy by breaking down glucose, both release energy
DIFFERENCES
oxygen is present
no oxygen present
! ! ! !
Pathway!
Substrate Level Phosphorylation
Oxidative Phosphorylation
Total ATP
Glycolysis
2ATP! !
2NADH = 3ATP
5 ATP
Transition!
———————!
2NADH = 5 ATP!
5 ATP
Krebs!
2 ATP!
6 NADH = 15 ATP! 2 FADH2= 3 ATP! 2 GTP = 2 ATP
20 ATP
TOTAL
4 ATP
28 ATP
30 ATP
! ! ! ! Energy Generation in Chloroplasts! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! Independent and Dependant Reactions!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!
!
!
PHOTOSYNTHESIS!
Capture Light Enerrgy! ! Light Reactions! Dark Reaction! ! ! ! ! ! (Photophosphorylation)!! ! ! Produce Carbohydrates! ! ! ! ! ! ! Reduced Energized! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! G3P! ! ! ! Water Split (photolysis)! ! ! Energized ! Must G3P Glucose, ! starch and used to ! ! ! Oxygen is Realized! ! ! ! ETC! cellulose regenerate ! ! ! ! ! ! ! ! ! ! ! ! ! ! Chemiosmosis! RuBP
! !
!
!
!
!
!
!
!
Produce ATP
