CELLULAR RESPIRATION Chemical Pathways Chapter 9-3 http://www.clickatutor.com/mitochondria.jpg.
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Cellular RespirationCampbell Chapter 9
Slide shows modified from: Glenbrook High School AP site
http://gbs.glenbrook.k12.il.us/Academics/gbssci/bio/apbio/Index/index.htm
& Dr. Chuck Downing http://gohs.tvusd.k12.ca.us/TeacherWebs/Science/CDowning/default.aspx
http://www.clickatutor.com/mitochondria.jpg
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___________ use energy from sunlight or chemicals to make their own food
AUTOTROPHShttp://www.inclusive.co.uk/downloads/images/pics2/tree.gif
In the last chapter green plantsused ________________trap energy from __________ and make ______________
sunlightfood (glucose)
PHOTOSYNTHESIS
http://206.173.89.42/REALTYWITHALOHA_COM/piphoto/funny%20sun%20with%20sunglasses.gif
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We get our energy from the __________ plants made during _______________ when we eat plants or eat animals that ate the plants.
GLUCOSE
In this chapter we will learn how ______________ get their energy by
consuming other organisms.
Image from: http://ag.ansc.purdue.edu/sheep/ansc442/Semprojs/2003/spiderlamb/eatsheep.gif
HETEROTROPHS
http://www.cibike.org/Eating.htm
PHOTOSYNTHESIS
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In this chapter, we will learn how this glucose is ____________ by organisms and the _______ is stored as _______
What kind of organisms do this?
energybroken down
ATP
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Animals(Including humans)
ALL LIVING THINGS NEED ENERGY!All organisms burn glucose for fuel
fungi bacteriaplants
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PHOTOSYNTHESIS
___________ + _________ + ___________ →_______________ + __________6 CO2 6 H2O C6H12O6 6O2
_____________ + _________ →________ + __________ + __________
______________________________________________________________
CELLULAR RESPIRATIONC6H12O6 6O2
6 CO2 6 H2O
The two equations are exact opposites!
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OXIDATION REDUCTIONIs Loss of electrons Is Gain of
electronsRemove H Add HReleases energy Stores energyExergonic Endergonic
REMEMBER: OIL RIG
Loss of hydrogen atoms
Gain of hydrogen atoms
Energy
OXIDATION
REDUCTION
http://www1.istockphoto.com/file_thumbview_approve/777814/2/istockphoto_777814_oil_bonus_pack.jpg
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CELLULAR RESPIRATION happens __________ in ________________.
If all the energy was released in one step… most would be lost as ____________________!
http://plato.acadiau.ca/COURSES/comm/g5/Fire_Animation.gif
slowly many steps
light and heat
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THE BIG PICTURE PLAYED OUT BEFORE YOUR EYES...
http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html
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• Prevents energy release in 1 explosive step• Allows energy to be released slowly in steps and
captured as ATP• Electron route:
food → NADH → ETC → oxygen
ELECTRON TRANSPORT CHAIN
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Link to Example of Coupled Reaction with Delta G Values
Look at middle of page Titled “How Free Energy Works” section: delta G values are shown for ATP hydrolysis and NADH
http://www.chemistry.wustl.edu/~edudev/LabTutorials/Cytochromes/cytochromes.html
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MITOCHONDRIA = cell power plantSurrounded by ___________ membraneOuter membrane & Inner membrane
(called _______________ )
Space between inner membrane & outer membrane
= ____________________
Space inside cristae folds= _________________
INTERMEMBRANE SPACE
DOUBLE
MATRIX
CRISTAE
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Text
ATP Synthase
inner membrane impermeable to H+ ions; therefore creates a force/charge gradient or voltage difference; electropotential.
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FAD → FADH2
NAD+ → NADH
HIGH ENERGY ELECTRON CARRIERS
http://courses.bio.indiana.edu/L104-Bonner/Sp12/imagesSp12/L16/MPs.htmlGREAT ANIMATION OF ELECTRON PUSH!! WATCH THIS!!
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See glycolysis movie
http://www.northland.cc.mn.us/biology/biology1111/animations/glycolysis.html
The first step in cellular respiration = _______________
Also called _________________________________
• happens in the ________________ outside the mitochondria• occurs _________________________
GLYCOLYSIS
CYTOPLASM
with or without oxygen
Embden-Meyerhoff Pathway
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• Details of glycolysis
Steps – A fuelmolecule is energized,using ATP.
1 3
1
GlucosePREPARATORY
PHASE(energy investment)Step
2
3
4
Glucose-6-phosphate
Fructose-6-phosphate
Glyceraldehyde-3-phosphate (G3P)
Step A six-carbonintermediate splits into two three-carbon intermediates.
4
Step A redoxreaction generatesNADH.
55 ENERGY PAYOFF
PHASE
1,3-Diphosphoglyceric acid(2 molecules)
6
Steps – ATPand pyruvic acidare produced.
6 9 3-Phosphoglyceric acid(2 molecules)7
2-Phosphoglyceric acid(2 molecules)8
2-Phosphoenolpyruvate(2 molecules)
9
(2 moleculesper glucose molecule)
Pyruvic acid
Fructose-1,6-diphosphate
Arraugh!
Like, this
is way hard!
Arraugh!
Like, this
is way hard!
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Glycolysis (GLYKOS = ________ LYSIS= ___________ )
Requires ____________to get it started.
Split apartsweet
ENERGY
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MITOCHONDRION
= using energy from breaking a chemical bond of a substrate(like glucose) to add a P directly from a phosphorylated molecule to ADP without a proton gradient.
(glycolysis is substrate-levelphosphorylation and NOT very efficient)
SUBSTRATE LEVEL PHOSPHORYLATION
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PYRUVIC ACID MOVES TO NEXT STEP
IF THERE IS NO OXYGEN (______________)
IF THERE IS OXYGEN (_____________)
= ANAEROBIC
= AEROBIC
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Cellular respiration
•Glycolysis: cytosol; glucose → pyruvate
•Kreb’s Cycle: •mitochondrial matrix;
•pyruvate → CO2
•NADH made
Electron Transport Chain: cristae; NADH & FADH2 donate electrons → oxygen
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Pyruvate is transported into mitochondrion and Acetyl CoA produced
For each pyruvate converted into acetyl CoA 1 molecule of CO2 is released;NAD+ ---> NADH;Coenzyme A (from B vitamin)
Krebs Cycle Animation-
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Kreb’s Cycle =Citric Acid Cycle
OAA CITRIC ACID
Krebs Cycle Animation
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Kreb’s Cycle• Oxaloacetate (OAA) combines with 2 C’s
from Acetyl CoA to make Citric acid• CoA recycles• 2 C atoms from pyruvate → exit as CO2
For each pyruvate that enters:
2 CO2 released 3 NAD+ reduced to 3 NADH; 1 FAD+ reduced to 1 FADH2 (riboflavin, B vitamin); 1 ATP molecule
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Electron transport chain
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ATP Synthase: The machine that keeps on turnin’........
• http://vcell.ndsu.edu/animations/atpgradient/index.htm (great animation)
• Real in-vivo video of ATP synthase action in live cell:
• http://www.youtube.com/watch?v=QeHCAFKaWM8• ATP cycle animation (slapping a phosphate on)
– http://www.youtube.com/watch?v=Lx9GklK0xQg
– Advanced animations (awesome if you have time) scroll down to metabolic/respiration
» http://www.youtube.com/watch?v=Lx9GklK0xQg26
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Why don't bothelectron carriersmake the sameamount of ATP?
Why don't bothelectron carriersmake the sameamount of ATP?
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More on Making ATP
• 3 places in the chain make ATP
NADH
FADH2
• Electrons from NADH start “higher” in the waterfall, so they generate more ATP than FADH2 electrons, which start “lower” in the waterfall and miss one ATP-generating step.
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Electron transport chain• ETC includes
Cytochromes Ubiquinone (Q)
• NADH & FADH2 pass electrons pass down ETC
• Energy from moving electrons concentrates H+ ions in __________________
• ________________: harnesses the flow of H+ back into the matrix make ATP (oxidative phosphorylation)
• ________ is final electron acceptor → ________
intermembrane space
ATP synthase
Oxygen H2O
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Cellular Respiration Grand Total• Glycolysis: →2 ATP
(substrate-level phosphorylation)
• Kreb’s Cycle:→ 2 ATP (substrate-level phosphorylation)
• Electron transport & oxidative phosphorylation: 2 NADH (glycolysis) → 6ATP 2 NADH (acetyl CoA) →6ATP 6 NADH (Kreb’s) → 18 ATP 2 FADH2 (Kreb’s) → 4 ATP
38 TOTAL ATP from 1 molecule of glucose (-2 ATP to transport 2 pyruvate into mitochondria)
NET of 36 ATP
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WHAT IF THERE IS NO OXYGEN?
IF THERE IS NO OXYGEN (______________)
IF THERE IS OXYGEN (_____________)
= ANAEROBIC
= AEROBIC
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Related metabolic processes
Fermentation:• alcohol~
pyruvate →ethanol • lactic acid~
pyruvate → lactate
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_______ +_____ →__________ + ______ + _____
ALCOHOLIC FERMENTATION
PYRUVIC
ACID
ALCOHOL
• Happens when yeast makes bread dough rise• CO2 bubbles make air spaces in bread• Alcohol evaporates during cooking
CO2 NAD+
http://www.deliciousdelicious.com/archives/herb%20bread%201.jpg
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_______ +_____ →__________ + ______ + _____
ALCOHOLIC FERMENTATION
PYRUVIC
ACID
ALCOHOL
Used to makealcoholic beverages
CO2 NAD+
http://www.firstpath.com/images/alcohol.jpg
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_______ +_____ →______________ + ________
LACTIC ACID FERMENTATION
PYRUVIC
ACID
LACTIC ACID
Happens in muscles during exercise when body can’t get oxygen to tissues fast enough.
Lactic acid builds up in muscles causing soreness
NAD+
http://www.miranda.com/library.en/Images/Pictures/girls-runners.jpg
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_______ +_____ →______________ + ________
LACTIC ACID FERMENTATION
PYRUVIC
ACID
LACTIC ACID
Happens when bacteria are used to make foods and beverages like yogurt, cheese,buttermilk, sauerkraut, kimchi
NAD+
http://chronicle.augusta.com/images/headlines/032200/DANNON_YOGURT.jpghttp://www.reillydairy.com/natural_cheese.html
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WITHOUT OXYGEN, PYRUVIC ACID ___________ and all the _______ carriers get full.
Eventually glycolysis will
WHY DO FERMENTATION?WHY NOT JUST KEEP MAKING ATP USING GLYCOLYSIS?
builds up
NAD+
NAD+
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_______ +_____ →__________ + ______ + _____
FERMENTATION HAPPENS so cells can ____________________ needed to keep glycolysis going
PYRUVIC
ACIDALCOHOL
→
CO2 NAD+
REGENERATE the NAD+
LACTIC ACID NAD+
→
You get the NAD+ carriers back
______
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__________________________= organisms that can make ATP using
either fermentation or cellular respiration
Ex: yeast and many bacteria
With oxygen pyruvate → Krebs cycle
Without oxygen → fermentation
FACULTATIVE ANAEROBES
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Organisms can use a variety of molecules for fuel
__________________=breakdown of fatty acids into 2 carbon fragments that enter Krebs cycle as acetyl CoA
1 g of fat → twice as muchATP as 1 g of carbohydrate
Beta oxidation=
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Evolutionary Significance• Most widespread metabolic pathway… suggests ancient
prokaryotes probably used glycolysis to make ATP before oxygen was present
• Earliest fossil bacteria present 3.5 billion years ago but large amounts of oxygen not present until 2.7 billion years ago
• Glycolysis happens in cytoplasm without membrane bound organelles suggests it was found in early prokaryotic cellssince eukaryotes appeared 1 billion years after prokaryotes (Endosymbiotic theory)
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VOCAB OVERLOAD ?
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CHEMIOSMOSIS
http://student.ccbcmd.edu/~gkaiser/biotutorials/energy/atpsynthase_il.html
= Generation of ATP from a proton gradient. It occurs in all living things Chloroplasts
do it to make ATP in light reactions
Mitochondria do itto make ATP following ETC
Prokaryotes creategradient across cellmembrane to make ATPto pump nutrients & waste and move flagella
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PHOTOPHOSPHORYLATION= Using hydrogen gradient generated by
thylakoid membrane during the light reactions of photosynthesis to make ATP
CHLOROPLAST
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MITOCHONDRION
= using proton gradient created by electron transport chain in cristae membrane to make ATP
OXIDATIVE PHOSPHORYLATION
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MITOCHONDRION
= using energy from breaking a chemical bond to add a P directly from a phosphorylated molecule to ADP without a proton gradient
SUBSTRATE LEVEL PHOSPHORYLATION
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Feedback mechanisms control cellular respiration (All arrows are reversible)
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http://www.wiley.com/college/boyer/0470003790/animations/glycolysis/glycolysis.htm
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Many Regulatory Steps Control Cell Respiration
• Main regulatory step in cell respiration occurs at beginning during glycolysis.
• An enzyme called PFK (phosphfructokinase) plays major role in regulating ATP production in Kreb’s.
• http://www.wiley.com/college/fob/quiz/quiz14/14-22.html• Allosteric regulation of phosphofructokinase sets the pace of respiration.
• This enzyme catalyzes the earliest step that irreversibly commits the substrate to glycolysis.
• Phosphofructokinase is an allosteric enzyme with receptor sites for specific inhibitors and activators.
• It is inhibited by ATP and stimulated by AMP (derived from ADP).
◦ When ATP levels are high, inhibition of this enzyme slows glycolysis.
◦ As ATP levels drop and ADP and AMP levels rise, the enzyme becomes active again and glycolysis speeds up.
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DNP: DiNitroPhenol; the “ATP uncoupler” (weight loss gone bad)• Uncoupling reagents (uncouplers)
are lipid-soluble weak acids. For example, H+ (shown in red) can dissociate from the hydroxyl group of the uncoupler dinitrophenol.
• Uncouplers dissolve in the membrane, and function as carriers for H+
• This makes inner membrane of
mitochondria PERMEABLE to H ions
• Uncouplers block oxidative phosphorylation by dissipating the H+ electrochemical gradient. (There is no longer an electric potential to PUSH the ATP synthase).
• The motion of H+ diffusion is lost as heat and does NO WORK; INCREASED FATTY ACID AND AMINO ACID METABOLISM; LOW ATP LEVELS AS GLYCOLYSIS IS INCREASED; PFK NO LONGER INHIBITED BECAUSE ATP LEVELS ARE LOW...
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Protein Structure Flashback!!PFK (Phosphofructokinase)
• http://www.wiley.com/college/boyer/0470003790/structure/pfk/pfk_intro.htm
• Example of ALLOSTERIC control; addition and removal of phosphates is the #1 regulatory mechanism of biological pathways.
• Enzymes that ADD a phosphate group are called KINASES (“Kinetic/motion/”turn on”) because they ACTIVATE another molecule.
• http://www.rpi.edu/dept/bcbp/yesterday/molbiochem/MBWeb/mb1/part2/glycolysis.htm#animat2
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CELL RESPIRATION RAP!!
• http://www.youtube.com/watch?v=VCpNk92uswY
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