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

___________ 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

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

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

Animals(Including humans)

ALL LIVING THINGS NEED ENERGY!All organisms burn glucose for fuel

fungi bacteriaplants

PHOTOSYNTHESIS

___________ + _________ + ___________ →_______________ + __________6 CO2 6 H2O C6H12O6 6O2

_____________ + _________ →________ + __________ + __________

______________________________________________________________

CELLULAR RESPIRATIONC6H12O6 6O2

6 CO2 6 H2O

The two equations are exact opposites!

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

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

• 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

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.

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!!

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

• 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)

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Steps – ATPand pyruvic acidare produced.

6 9 3-Phosphoglyceric acid(2 molecules)7

2-Phosphoglyceric acid(2 molecules)8

2-Phosphoenolpyruvate(2 molecules)

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(2 moleculesper glucose molecule)

Pyruvic acid

Fructose-1,6-diphosphate

Arraugh!

Like, this

is way hard!

Arraugh!

Like, this

is way hard!

Glycolysis (GLYKOS = ________ LYSIS= ___________ )

Requires ____________to get it started.

Split apartsweet

ENERGY

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

PYRUVIC ACID MOVES TO NEXT STEP

IF THERE IS NO OXYGEN (______________)

IF THERE IS OXYGEN (_____________)

= ANAEROBIC

= AEROBIC

Cellular respiration

•Glycolysis: cytosol; glucose → pyruvate

•Kreb’s Cycle: •mitochondrial matrix;

•pyruvate → CO2

•NADH made

Electron Transport Chain: cristae; NADH & FADH2 donate electrons → oxygen

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-

Kreb’s Cycle =Citric Acid Cycle

OAA CITRIC ACID

Krebs Cycle Animation

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

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

Why don't bothelectron carriersmake the sameamount of ATP?

Why don't bothelectron carriersmake the sameamount of ATP?

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.

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

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

WHAT IF THERE IS NO OXYGEN?

IF THERE IS NO OXYGEN (______________)

IF THERE IS OXYGEN (_____________)

= ANAEROBIC

= AEROBIC

Related metabolic processes

Fermentation:• alcohol~

pyruvate →ethanol • lactic acid~

pyruvate → lactate

_______ +_____ →__________ + ______ + _____

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

_______ +_____ →__________ + ______ + _____

ALCOHOLIC FERMENTATION

PYRUVIC

ACID

ALCOHOL

Used to makealcoholic beverages

CO2 NAD+

http://www.firstpath.com/images/alcohol.jpg

_______ +_____ →______________ + ________

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

_______ +_____ →______________ + ________

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

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+

_______ +_____ →__________ + ______ + _____

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

______

__________________________= 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

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=

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)

VOCAB OVERLOAD ?

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

PHOTOPHOSPHORYLATION= Using hydrogen gradient generated by

thylakoid membrane during the light reactions of photosynthesis to make ATP

CHLOROPLAST

MITOCHONDRION

= using proton gradient created by electron transport chain in cristae membrane to make ATP

OXIDATIVE PHOSPHORYLATION

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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