2.2 cellular respiration: the details ► goals; break the bonds b/w the 6 c atoms of glucose,...

2.2 Cellular Respiration: The 2.2 Cellular Respiration: The DetailsDetails

►Goals;Goals; Break the bonds b/w the 6 C atoms of Break the bonds b/w the 6 C atoms of

glucose, resulting in 6 COglucose, resulting in 6 CO22 molecules molecules Move H atom electrons from glucose to Move H atom electrons from glucose to

oxygen, forming 6 water moleculesoxygen, forming 6 water molecules Trap as much of the free energy released Trap as much of the free energy released

in the process as possible in the form of in the process as possible in the form of ATPATP

Overview of cellular Overview of cellular respirationrespiration

► 4 metabolic stages4 metabolic stages Anaerobic respirationAnaerobic respiration

1. 1. Glycolysis (substrate level Glycolysis (substrate level phosphorylation)phosphorylation) respiration without Orespiration without O22

in cytosolin cytosol

Aerobic respirationAerobic respiration respiration using Orespiration using O22

in mitochondriain mitochondria

2. 2. Pyruvate oxidationPyruvate oxidation3. 3. Krebs cycleKrebs cycle4. 4. Electron transport chain and Electron transport chain and

chemiosmosis (oxidative chemiosmosis (oxidative phosphorylation)phosphorylation)

C6H12O6 6O2 ATP 6H2O 6CO2+ + + (+ heat)

Energy TransferEnergy Transfer

► How is the chemical potential energy How is the chemical potential energy in glucose transformed into ATP?in glucose transformed into ATP?

1.1. Substrate-Level PhosphorylationSubstrate-Level Phosphorylation

2.2. Oxidative PhosphorylationOxidative Phosphorylation

Substrate-Level PhosphorylationSubstrate-Level Phosphorylation

►A molecule containing a phosphate A molecule containing a phosphate transfers it to ADP (with the aid of transfers it to ADP (with the aid of enzymes), forming ATP. 31kJ/mol of enzymes), forming ATP. 31kJ/mol of free energy is also transferred.free energy is also transferred.

►For each glucose molecule, 4 ATP are For each glucose molecule, 4 ATP are made this way in glycolysis (stage 1) made this way in glycolysis (stage 1) and 2 ATP in the Kreb’s cycle (stage 3)and 2 ATP in the Kreb’s cycle (stage 3)

Oxidative PhosphorylationOxidative Phosphorylation

► ATP is formed indirectly through a series of ATP is formed indirectly through a series of enzyme-catalyzed redox reactions involving enzyme-catalyzed redox reactions involving oxygen as the final electron acceptoroxygen as the final electron acceptor

► It begins when the compound NAD+ It begins when the compound NAD+ (nicotinamide adenine dinucleotide), which (nicotinamide adenine dinucleotide), which is a coenzyme, removes 2 H atoms (2 is a coenzyme, removes 2 H atoms (2 protons and 2 electrons) from glucose. protons and 2 electrons) from glucose.

► 2 electrons and 1 proton attach and reduce 2 electrons and 1 proton attach and reduce NAD+ to NADH, while the left over proton NAD+ to NADH, while the left over proton dissolves in surrounding solution H+dissolves in surrounding solution H+(aq)(aq)


►NADH is formed during glycolysis, pyruvate NADH is formed during glycolysis, pyruvate oxidation and 3 times in the Kreb’s cycleoxidation and 3 times in the Kreb’s cycle

► A dehydrogenase enzyme catalyzes this rxn.A dehydrogenase enzyme catalyzes this rxn.► FAD (flavin adenine dinucleotide) also acts FAD (flavin adenine dinucleotide) also acts

like NAD+ and is reduced by 2 H atoms from like NAD+ and is reduced by 2 H atoms from glucose to form FADHglucose to form FADH2 2 (occurs in Kreb’s (occurs in Kreb’s cycle)cycle)

► These reductions are both energy These reductions are both energy harvesting rxns that will later transfer most harvesting rxns that will later transfer most of their free energy to ATPof their free energy to ATP


►These co-enzymes (reduced FADHThese co-enzymes (reduced FADH22 and NADH) function as energy carriersand NADH) function as energy carriers

►So, how does the free energy get So, how does the free energy get transferred to ATP? It occurs in Stage transferred to ATP? It occurs in Stage 4 (electron transport and 4 (electron transport and chemiosmosis) and requires oxygen…chemiosmosis) and requires oxygen…discussed later!discussed later!

Aerobic respiration happens in Aerobic respiration happens in 44 stages:stages:

Stage 1Stage 1 – – Glycolysis Glycolysis (10 step process occurring in cytoplasm)(10 step process occurring in cytoplasm)

glycoglyco lysislysis

glucose splittingglucose splitting

►Stage 2-Pyruvate oxidation-1 step process Stage 2-Pyruvate oxidation-1 step process occurring in the mitochondrial matrixoccurring in the mitochondrial matrix

►Stage 3-Kreb’s Cycle (citric acid cycle) 8 Stage 3-Kreb’s Cycle (citric acid cycle) 8 step cyclical process occurring in the step cyclical process occurring in the mitochondrial matrixmitochondrial matrix

►Stage 4 Electron Transport and Stage 4 Electron Transport and chemiosmosis (oxidative phosphorylation) chemiosmosis (oxidative phosphorylation) multi step process occurring in the inner multi step process occurring in the inner mitochondrial membrane (cristae)mitochondrial membrane (cristae)

intermembranespace inner

membrane

outermembrane

matrix

cristae

Mitochondria — StructureMitochondria — Structure► Double membrane energy harvesting organelleDouble membrane energy harvesting organelle

smooth outer membranesmooth outer membrane highly folded inner membranehighly folded inner membrane

► cristaecristae intermembrane spaceintermembrane space

► fluid-filled space between membranesfluid-filled space between membranes matrixmatrix

► inner fluid-filled spaceinner fluid-filled space DNA, ribosomesDNA, ribosomes enzymesenzymes

► free in matrix & membrane-bound free in matrix & membrane-bound

mitochondrialDNA

What cells would have a lot of mitochondria?

In glycolysis, a glucose molecule (6 carbon) is broken down into two 3-carbon pyruvate (pyruvic acid) molecules.

energy released to make small quantity of ATP(2 molecules)

series of enzyme controlled reactions

pyruvic acid

glucose

Glycolysis does not require oxygen

-ate or acid???-ate or acid???

►-ate replaces the word acid in organic -ate replaces the word acid in organic acids to indicate the ionized form of acids to indicate the ionized form of the acidthe acid

►E.g. pyruvic acid-pyruvateE.g. pyruvic acid-pyruvate►E.g. aspartic acid-aspartateE.g. aspartic acid-aspartate

Fig 11 (p.98)Fig 11 (p.98)

► The overall chemical equation for glycolysisThe overall chemical equation for glycolysis

glucose + 2ADP + 2Pi + 2NAD+glucose + 2ADP + 2Pi + 2NAD+ 2 pyruvate + 2ATP + 2(NADH + 2 pyruvate + 2ATP + 2(NADH + H+)H+)

► The energy yield for glycolysisThe energy yield for glycolysis

4 ATP produced4 ATP produced

2 2 ATP usedATP used

2 ATP produced net (can be used immediately)2 ATP produced net (can be used immediately)

2 NADH produced (used later to obtain more ATP)2 NADH produced (used later to obtain more ATP)

GlycolysisGlycolysis

► Alone, this process is not efficient in Alone, this process is not efficient in transferring energy from glucose (only transferring energy from glucose (only 2.2%)2.2%)

► Some is lost as heat but most of the energy Some is lost as heat but most of the energy is trapped in the pyruvate and NADHis trapped in the pyruvate and NADH

►Glycolysis is thought to be the earliest form Glycolysis is thought to be the earliest form of energy metabolism. of energy metabolism.

► Video -http://www.youtube.com/watch?v=x-Video -http://www.youtube.com/watch?v=x-stLxqPt6EstLxqPt6E

► Song-http://www.youtube.com/watch?Song-http://www.youtube.com/watch?v=6JGXayUyNVwv=6JGXayUyNVw

Your turn…Your turn…

►Read p.94-100 and note sheetsRead p.94-100 and note sheets►Answer Q 1-10 on p.115Answer Q 1-10 on p.115►Fill out glycolytic PathwayFill out glycolytic Pathway►Quiz on Wednesday, October 13th (all Quiz on Wednesday, October 13th (all

10 steps with enzymes)10 steps with enzymes)

Stage 2 – Stage 2 – Pyruvate oxidationPyruvate oxidation

► The pyruvic acid made in The pyruvic acid made in glycolysis glycolysis (stage1)(stage1) still contains a still contains a lot of energy and are transported lot of energy and are transported through the mitochondrial through the mitochondrial membranes into the matrixmembranes into the matrix

►A multi-enzyme complex catalyzes A multi-enzyme complex catalyzes 3 changes3 changes

Pyruvate oxidationPyruvate oxidation

1.1. A carboxyl group is removed as COA carboxyl group is removed as CO2 2 (a (a decarboxylation rxn using the enzyme decarboxylation rxn using the enzyme pyruvate decarboxylase)pyruvate decarboxylase)

2.2. NADNAD++ is reduced by 2 H atoms (food) to form is reduced by 2 H atoms (food) to form NADH. The NADNADH. The NAD++ oxidizes the 2-C portion oxidizes the 2-C portion and becomes acetic acid. This is a redox rxn and becomes acetic acid. This is a redox rxn as pyruvate is oxidized and NADas pyruvate is oxidized and NAD+ + is reducedis reduced

3.3. Coenzyme A (contains S) is attached to the Coenzyme A (contains S) is attached to the remaining acetic acid portion to form acetyl-remaining acetic acid portion to form acetyl-CoA in an unstable bond (sets it up for stage CoA in an unstable bond (sets it up for stage 3)3)

Pyruvate oxidation Pyruvate oxidation equationequation

2 pyruvate + 2 NAD2 pyruvate + 2 NAD++ + 2 CoA 2 acetyl-CoA + 2 NADH + 2 H + 2 CoA 2 acetyl-CoA + 2 NADH + 2 H++ + 2 CO+ 2 CO22

Where do the products go?Where do the products go?► Acetyl-CoA move to stage 3-Krebs CycleAcetyl-CoA move to stage 3-Krebs Cycle►NADH move to stage 4-Electron NADH move to stage 4-Electron

Transport/Chemiosmosis (produce ATP by Transport/Chemiosmosis (produce ATP by oxidative phosphorylation)oxidative phosphorylation)

► COCO22 exits as waste exits as waste►HH++ remain dissolved in the matrix remain dissolved in the matrix

What exactly is Acetyl CoA?What exactly is Acetyl CoA?► It is multifunctional; If the body needs It is multifunctional; If the body needs

energy it moves into the Kreb’s cycle, energy it moves into the Kreb’s cycle, if not it produces lipids (energy if not it produces lipids (energy storing)storing)

►Many nutrients catabolized for energy Many nutrients catabolized for energy are converted to acetyl-CoA and then are converted to acetyl-CoA and then channeled toward fat or ATP channeled toward fat or ATP production-depending on energy production-depending on energy needs.needs.

Anaerobic Anaerobic RespirationRespiration(in animals)(in animals)

anaerobic = in the absence of anaerobic = in the absence of oxygenoxygen

In In lowlow oxygen conditions or oxygen conditions or during during heavy exerciseheavy exercise, when , when

not enough oxygen can be not enough oxygen can be supplied, muscle cells swap to supplied, muscle cells swap to

anaerobicanaerobic respirationrespiration

glycolysis still happens as it does not require oxygen

in absence of oxygen pyruvic acid is turned into lactic acid.

pyruvic acid

lactic acid

glucose

2 ADP + 2 Pi

2 ATP

A build up of lactic acid produces A build up of lactic acid produces musclemuscle fatiguefatigue. .

Muscle fatigue makes muscles ache and Muscle fatigue makes muscles ache and contract less powerfully.contract less powerfully.

A recovery period is needed. During this time A recovery period is needed. During this time more more oxygenoxygen is taken in to convert the lactic is taken in to convert the lactic acid back into pyruvic acid again.acid back into pyruvic acid again.

The volume of oxygen needed is called the The volume of oxygen needed is called the

oxygenoxygen debtdebt..

SummarySummary

oxygen debte.g. during hard exercise

oxygen debtrepaid during recovery time

glucose

pyruvic acid

lactic acid

Anaerobic Anaerobic Respiration Respiration

in plantsin plants

The same process occurs in The same process occurs in plants and yeast in low plants and yeast in low oxygen conditions, e.g. oxygen conditions, e.g. muddy, flooded soils.muddy, flooded soils.

glycolysis still happens, producing 2 ATP molecules

This time in absence of oxygen, pyruvic acid is turned into carbon dioxide and ethanol

glucose

pyruvic acid

ethanol + carbon dioxide

This is irreversible

2 ADP + 2 Pi

2 ATP

Comparison of aerobic and Comparison of aerobic and anaerobic respirationanaerobic respiration

Aerobic Aerobic respirationrespiration

Anaerobic RespirationAnaerobic Respiration

in animalsin animals in plants and yeastin plants and yeast

Oxygen required?Oxygen required? yesyes nono nonoGlycolysis occursGlycolysis occurs yesyes yesyes yesyesATP yieldATP yield 38ATP38ATP 2ATP2ATP 2ATP2ATPGlucose completely broke Glucose completely broke

down?down? yesyes nono nonoEnd productsEnd products Carbon Carbon

dioxide dioxide and and waterwater

Lactic Lactic acidacid

Ethanol Ethanol and carbon and carbon dioxidedioxide

Fermentation (anaerobic)Fermentation (anaerobic)

►Bacteria, yeastBacteria, yeast

1C3C 2Cpyruvate ethanol + CO2

►Animals, some fungiAnimals, some fungi

pyruvate lactic acid3C 3C

►beer, wine, breadbeer, wine, bread

►cheese, anaerobic exercise (no Ocheese, anaerobic exercise (no O22))

NADH NAD+

NADH NAD+

back to glycolysis

back to glycolysis

recycleNADH

Alcohol FermentationAlcohol Fermentation

1C3C 2Cpyruvate ethanol + CO2

NADH NAD+

Dead end process at ~12% ethanol,

kills yeast can’t reverse the

reaction

bacteria yeast

back to glycolysis

recycleNADH

Reversible process once O2 is available,

lactate is converted back to pyruvate by the liver

Lactic Acid FermentationLactic Acid Fermentationpyruvate lactic acid

3C 3CNADH NAD+

O2

animalssome fungi

back to glycolysis

Pyruvate is a branching pointPyruvate is a branching point

PyruvatePyruvate

O2O2

mitochondriaKrebs cycle

aerobic respiration

fermentationanaerobicrespiration

Stage 3: Kreb’s CycleStage 3: Kreb’s Cycle

►8-step process catalyzed by enzymes8-step process catalyzed by enzymes►Considered cyclic b/c oxaloacetate (the Considered cyclic b/c oxaloacetate (the

product of step 8) is the reactant in step product of step 8) is the reactant in step 11

►Cycles through twice for every glucose Cycles through twice for every glucose molecule as there are 2 molecules of molecule as there are 2 molecules of acetyl CoA.acetyl CoA.

►Equation;Equation;Oxaloacetate + acetyl-CoA +ADP +Pi +3 NADOxaloacetate + acetyl-CoA +ADP +Pi +3 NAD++ + FAD CoA + ATP + + FAD CoA + ATP +

3 NADH + 3H3 NADH + 3H++ + FADH + FADH22 + 2 CO + 2 CO22 + oxaloacetate + oxaloacetate

The Krebs CycleThe Krebs Cycle► Occurs in the matrix of the mitochondrion. Occurs in the matrix of the mitochondrion.

Transfers energy from organic molecules to ATP, Transfers energy from organic molecules to ATP, NADH, FADHNADH, FADH2 2 and removes C atoms as COand removes C atoms as CO22

► Aerobic phase (requires oxygen). By the end of Aerobic phase (requires oxygen). By the end of the Kreb’s Cylce the original glucose molecule is the Kreb’s Cylce the original glucose molecule is entirely consumedentirely consumed

StepsSteps1.1. 2-carbon acetyl CoA2-carbon acetyl CoA joins with a joins with a 4-carbon 4-carbon

compound (oxaloacetate)compound (oxaloacetate) to form a to form a 6- carbon 6- carbon compound compound calledcalled Citrate. CoA is released Citrate. CoA is released (recycled)(recycled)

The Krebs CycleThe Krebs Cycle

StepsSteps

2.2. Citrate (6-C) is re-arranged to Citrate (6-C) is re-arranged to isocitrate (6-C)isocitrate (6-C)

3.3. Isocitrate is converted to alpha-Isocitrate is converted to alpha-ketoglutarate (5-C) by losing a COketoglutarate (5-C) by losing a CO22 and 2 H atoms that reduce NADand 2 H atoms that reduce NAD++ to to NADHNADH


StepsSteps4. Alpha-ketoglutarate (5-C) is converted 4. Alpha-ketoglutarate (5-C) is converted

into succinyl CoA (4-C). One COinto succinyl CoA (4-C). One CO22 is is removed, coenzyme A is added and 2 removed, coenzyme A is added and 2 H atoms reduce NADH atoms reduce NAD++ to NADH. to NADH.

5. Succinyl CoA (4-C) is converted to 5. Succinyl CoA (4-C) is converted to succinate (4-C). ATP is formed by succinate (4-C). ATP is formed by substrate level phosphorylation and substrate level phosphorylation and coenzyme A is releasedcoenzyme A is released


StepsSteps6. Succinate (4-C) is converted to fumarate 6. Succinate (4-C) is converted to fumarate

(4-C). Two H reduce FAD to FADH(4-C). Two H reduce FAD to FADH22

7. Fumarate (4-C) is converted to malate 7. Fumarate (4-C) is converted to malate (4-C). This is a hydrolysis rxn(4-C). This is a hydrolysis rxn

8. Malate (4-C) is converted to 8. Malate (4-C) is converted to oxaloacetate (4-C). Two H reduce NADoxaloacetate (4-C). Two H reduce NAD++ to NADHto NADH

HighlightsHighlights

►Video-http://www.youtube.com/watch?Video-http://www.youtube.com/watch?v=XVWdeKoiEOcv=XVWdeKoiEOc

►Energy is harvested in steps 3 (NADH), Energy is harvested in steps 3 (NADH), 4 (NADH) , 5 (ATP-substrate-level 4 (NADH) , 5 (ATP-substrate-level phosphorylation), 6 (FADHphosphorylation), 6 (FADH22), 8 (NADH)), 8 (NADH)

►The last 4 C atoms of the original The last 4 C atoms of the original glucose leave as COglucose leave as CO22 (waste) (waste)

Grand Total so far…Grand Total so far…► Glycolysis (2 ATP, 2 NADH)Glycolysis (2 ATP, 2 NADH)► Pyruvate oxidation (2 NADH, 2 COPyruvate oxidation (2 NADH, 2 CO22))► Kreb’s Cycle (after 2 cycles)Kreb’s Cycle (after 2 cycles)

6 NADH6 NADH 2 FADH2 FADH22

2 ATP2 ATP 4 CO4 CO22

► The 12 reduced coenzymes (energy The 12 reduced coenzymes (energy carriers) will eventually be transferred to carriers) will eventually be transferred to ATP in stage 4ATP in stage 4

Where did all the carbons go?Where did all the carbons go?►6-C (glucose) at the end of glycolysis 6-C (glucose) at the end of glycolysis

is transformed into two 3-C pyruvateis transformed into two 3-C pyruvate►After pyruvate oxidation you are left After pyruvate oxidation you are left

with two COwith two CO22 and two acetyl CoA (2 and two acetyl CoA (2 carbons each)carbons each)

►Once the Kreb’s Cycle is completed Once the Kreb’s Cycle is completed you lose the last four original carbons you lose the last four original carbons as COas CO22

Cellular RespirationCellular RespirationStage 4Stage 4

ETC and ChemiosmosisETC and Chemiosmosis►Occurs in the inner mitochondrial membraneOccurs in the inner mitochondrial membrane► Requires oxygen (final acceptor of electrons Requires oxygen (final acceptor of electrons

in the ETC) without oxygen; Kreb’s, ETC and in the ETC) without oxygen; Kreb’s, ETC and chemiosmosis stop.chemiosmosis stop.

► Energy carriers (NADH and FADHEnergy carriers (NADH and FADH22) transfer ) transfer the H atom electrons to a series of the H atom electrons to a series of compounds (mostly proteins) in the Electron compounds (mostly proteins) in the Electron Transport Chain (ETC)Transport Chain (ETC)

ETCETC

Brief OverviewBrief Overview

►Electrons move through a series of Electrons move through a series of redox reactions that release the free redox reactions that release the free energy used to pump protons into the energy used to pump protons into the intermembrane space (this creates an intermembrane space (this creates an electrochemical gradient-source of electrochemical gradient-source of free energy)free energy)

Brief OverviewBrief Overview

►During chemiosmosis, protons move During chemiosmosis, protons move through ATPase complexes (within the through ATPase complexes (within the membrane) releasing free energy membrane) releasing free energy (drives the synthesis of ATP)(drives the synthesis of ATP)

VideosVideos

► Video-ETCVideo-ETC► http://www.youtube.com/watch?http://www.youtube.com/watch?

v=xbJ0nbzt5Kwv=xbJ0nbzt5Kw► Video-ChemiosmosisVideo-Chemiosmosis► http://www.youtube.com/watch?http://www.youtube.com/watch?

v=3y1dO4nNaKYv=3y1dO4nNaKY► Video-Oxidative PhosphorylationVideo-Oxidative Phosphorylation► http://www.youtube.com/watch?http://www.youtube.com/watch?

v=Idy2XAlZIVAv=Idy2XAlZIVA

ETCETC► The ETC is arranged in increasing The ETC is arranged in increasing

electronegativity (weakest attractor of electronegativity (weakest attractor of electrons at start to strongest at the end.)electrons at start to strongest at the end.)

► Each component is reduced (gaining 2 Each component is reduced (gaining 2 electrons from the component before) electrons from the component before) and oxidized (losing 2 electrons from the and oxidized (losing 2 electrons from the component after.)component after.)

► Electrons are shuttled through like a Electrons are shuttled through like a baton from start to finishbaton from start to finish

► As they move they become more stable As they move they become more stable as they get closer to the nuclei of the as they get closer to the nuclei of the atoms they associate with.atoms they associate with.

ETCETC

►Free energy is used to pump out H+ Free energy is used to pump out H+ protons into the intermembrane spaceprotons into the intermembrane space

►At the last component of the ETC, At the last component of the ETC, oxygen (highly electronegative) oxygen (highly electronegative) accepts (strips) the last 2 electrons accepts (strips) the last 2 electrons and together with 2 protons from the and together with 2 protons from the matrix, forms watermatrix, forms water

Actual components of ETCActual components of ETC

►NADH dehydrogenase, ubiquinone (Q), NADH dehydrogenase, ubiquinone (Q), cytochrome b-ccytochrome b-c1 1 complex, cytochrome complex, cytochrome c, cytochrome oxidase complex.c, cytochrome oxidase complex.

►The ETC is highly exergonicThe ETC is highly exergonic►The free energy lost by the electron The free energy lost by the electron

pair during transport is used to pump pair during transport is used to pump out H +.out H +.

Energy convertedEnergy converted

►Chemical potential energy of electron Chemical potential energy of electron position is converted to position is converted to electrochemical potential energy of a electrochemical potential energy of a proton gradient (accumulation of proton gradient (accumulation of charged protons).charged protons).

►FADHFADH22 passes on their electrons to passes on their electrons to complex Q (Ubiqinone)complex Q (Ubiqinone)

►2 ATP are formed for every FADH2 ATP are formed for every FADH22

►3 ATP are formed for every NADH3 ATP are formed for every NADH

Chemiosmosis and Oxidative Chemiosmosis and Oxidative SynthesisSynthesis

►The electrochemical gradient (of H+) The electrochemical gradient (of H+) stores free energystores free energy

►Creates a potential difference Creates a potential difference (voltage), like that of a battery(voltage), like that of a battery

►B/c they cannot pass through the B/c they cannot pass through the phospholipids bilayer, they must pass phospholipids bilayer, they must pass through proton channels associated through proton channels associated with ATP-synthase.with ATP-synthase.


► The free energy stored in the gradient The free energy stored in the gradient produces a PMF (proton-motive force) that produces a PMF (proton-motive force) that moves protons through ATPase complex.moves protons through ATPase complex.

► Free energy in gradient is reduced and is Free energy in gradient is reduced and is used to create ATP from (ADP and Pi)used to create ATP from (ADP and Pi)

► It is called chemiosmosis b/c the energy that It is called chemiosmosis b/c the energy that drives the synthesis of ATP comes from the drives the synthesis of ATP comes from the “osmosis” of protons through a membrane.“osmosis” of protons through a membrane.


►Once created ATP move into Once created ATP move into cytoplasm through facilitated diffusion cytoplasm through facilitated diffusion to do “work” (movement, cell division to do “work” (movement, cell division etc)etc)

Cellular Respiration Cellular Respiration SummarySummary

►Table 3 p.114Table 3 p.114

How much ATP is really How much ATP is really made?made?

►Theoretically 36 is made but as the Theoretically 36 is made but as the membrane is permeable (to protons) membrane is permeable (to protons) and some energy is used for other and some energy is used for other endergonic rxns, actual yield is about endergonic rxns, actual yield is about 30 ATP 30 ATP

►Efficiency of energy conversion is Efficiency of energy conversion is about 32%about 32%

Controlling Aerobic Controlling Aerobic RespirationRespiration

►Phosphofructokinase (enzyme at step Phosphofructokinase (enzyme at step 3 of glycolysis) controls cellular 3 of glycolysis) controls cellular respirationrespiration

► It is activated by ADP and citrateIt is activated by ADP and citrate► It is inhibited by ATPIt is inhibited by ATP►NADH inhibits pyruvate decarboxylase NADH inhibits pyruvate decarboxylase

(enzyme that converts pyruvate to (enzyme that converts pyruvate to acetyl CoA).acetyl CoA).

Metabolic RateMetabolic Rate

►Amount of energy consumed at a given Amount of energy consumed at a given time, and a measure of the overall rate time, and a measure of the overall rate at which the energy-yielding rxns of at which the energy-yielding rxns of cellular respiration takes place.cellular respiration takes place.

►BMR (Basal Metabolic Rate) is the BMR (Basal Metabolic Rate) is the minimum amount of energy for survival minimum amount of energy for survival (breathing, control temp.) Usually (breathing, control temp.) Usually accounts for 60-70% of daily energyaccounts for 60-70% of daily energy

Metabolic RateMetabolic Rate

►BMR CalculatorBMR Calculator►http://www.tlbc.ca/blog/index.php/bmr-http://www.tlbc.ca/blog/index.php/bmr-

calculator/calculator/►Varies with age, sex, healthVaries with age, sex, health

Looking back…Looking back…

►ATP is a high energy yielding ATP is a high energy yielding nucleotide that biological systems nucleotide that biological systems need to power rxns (muscle need to power rxns (muscle contractions, cell division)contractions, cell division)

►Glucose is broken down during cellular Glucose is broken down during cellular respiration (covalent bonds are split) respiration (covalent bonds are split) to provide energy for the synthesis of to provide energy for the synthesis of ATP. By-product is COATP. By-product is CO22..

Looking back…Looking back…

►The role of oxygen is to “grab” the The role of oxygen is to “grab” the excess H+ (don’t want the cell to be excess H+ (don’t want the cell to be too acidic) forming water.too acidic) forming water.

►Glucose is oxidized (into COGlucose is oxidized (into CO22) and ) and oxygen is reduced to Hoxygen is reduced to H22OO

PracticePractice

►WorksheetsWorksheets►P.115 Q12-18P.115 Q12-18

2.2 cellular respiration: the details ► goals; break the bonds b/w the 6 c atoms of glucose,...

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