CHAPTER 9CHAPTER 9

ENERGY IN A CELLENERGY IN A CELL

Presentation credentialsPresentation credentials

This is presentation is a mash up of This is presentation is a mash up of 3 different sources. They are:3 different sources. They are:

Taylor, J.(2010). Unit 4 Chemical Taylor, J.(2010). Unit 4 Chemical energy and ATP.energy and ATP.

Distarasiswa, D. (2010). Cellular Distarasiswa, D. (2010). Cellular Respiration.Respiration.

Ferguson, S. (2009).Energy in a cell.Ferguson, S. (2009).Energy in a cell.

ENERGYENERGY

All living organisms must be able to All living organisms must be able to obtain energy from their obtain energy from their environmentenvironment

All energy comes from All energy comes from sunlightsunlight and and organisms either obtain it directly or organisms either obtain it directly or indirectlyindirectly

ADENOSINE ADENOSINE TRIPHOSPHATETRIPHOSPHATE

((ATP)ATP)

Energy storing molecule.Energy storing molecule.

Releases energy quickly whenever a Releases energy quickly whenever a cell needs it.cell needs it.

ATP StructureATP Structure

Composed of an adenosine molecule with Composed of an adenosine molecule with three phosphate molecules attached.three phosphate molecules attached.

The energy of ATP becomes available The energy of ATP becomes available when the bond is broken between the when the bond is broken between the 22ndnd and 3and 3rdrd phosphate groups. phosphate groups.

adenosineadenosineTRITRIphosphate to adenosinephosphate to adenosineDIDIphosphatephosphate

ATPATP

PhotosynthesisPhotosynthesis

The process that The process that uses sunlight to uses sunlight to make simple make simple sugars.sugars.

Contains 2 Contains 2 reactions.reactions.

Light - dependent Light - dependent reactionreaction

Requires lightRequires light in order to occur. in order to occur.

Reactants:Reactants: Sunlight and water. Sunlight and water.

Products:Products: ATP and NADPH and ATP and NADPH and releases oxygen.releases oxygen.

Light - Independent Light - Independent ReactionReaction

Also known as the Also known as the dark cycledark cycle oror calvin calvin cycle.cycle.

Does not need sunlightDoes not need sunlight in order to occur. in order to occur.

Reactants:Reactants: ATP, NADPH, and Carbon ATP, NADPH, and Carbon dioxide.dioxide.

Products:Products: Glucose and Pgal. Glucose and Pgal.

Calvin Cycle

OR

Dark Cycle

Formula for Formula for photosynthesisphotosynthesis

6CO6CO22 + 6H + 6H22O + sunlight O + sunlight → C→ C66HH1212OO66 + 6O + 6O22

ChloroplastChloroplast

The plant organelle in which The plant organelle in which photosynthesis occurs.photosynthesis occurs.

Contains pigments called Contains pigments called chlorophyllchlorophyll that absorbs most that absorbs most wavelengths of light except green.wavelengths of light except green.

ChloroplastChloroplast

Aerobic Cellular Aerobic Cellular RespirationRespiration

(with Oxygen)(with Oxygen) Breakdown of sugar (food) into ATP Breakdown of sugar (food) into ATP

(usable energy).(usable energy). Occurs in the Occurs in the mitochondria.mitochondria.

3 phases:3 phases:1. 1. glycolysis:glycolysis: Anaerobic (no oxygen) Anaerobic (no oxygen)

*Steps 2&3 with oxygen*Steps 2&3 with oxygen2. 2. citric acid cyclecitric acid cycle (kreb cycle) (kreb cycle)3. 3. electron transport chainelectron transport chain

MitochondriaMitochondria

Formula for aerobic Formula for aerobic respirationrespiration

Opposite of photosynthesis.Opposite of photosynthesis.

CC66HH1212OO66 + O + O22 → 6CO→ 6CO22 + 6H + 6H22O + O + energyenergy

GLYCOLYSISGLYCOLYSIS(sugar splitting)(sugar splitting)

AnaerobicAnaerobic: : no oxygenno oxygen is used. is used. Takes the Takes the 6-Carbon glucose6-Carbon glucose and breaks it and breaks it

into into 2, 3-Carbon pyruvic acid2, 3-Carbon pyruvic acid molecules. molecules.

Glycolysis Cont…Only produces Only produces 2 ATP2 ATP molecules molecules

Glycolysis Cont…Glycolysis Cont…

Pyruvic acid is then converted into Pyruvic acid is then converted into Acetyl Co-enzyme AAcetyl Co-enzyme A before it enters before it enters the citric acid cycle.the citric acid cycle.

Reactants:Reactants: Glucose Glucose

Products:Products: Pyruvic Acid Pyruvic Acid

CITRIC ACID CYCLECITRIC ACID CYCLE(Also called the Kreb Cycle)(Also called the Kreb Cycle)

During this process high energy electrons are During this process high energy electrons are captured by captured by NADHNADH and and FADHFADH22. (electron . (electron carriers)carriers)

Pulls carbons off the sugar molecules, Pulls carbons off the sugar molecules, releasing carbon dioxide and generating releasing carbon dioxide and generating 2 2 ATP ATP (varies)(varies)..

Reactants:Reactants: Acetyl Co-enzyme A Acetyl Co-enzyme A Products:Products: NADH and FADH NADH and FADH22

Kreb CycleKreb Cycle((Citric Acid Cycle)Citric Acid Cycle)

ELECTRON TRANSPORT ELECTRON TRANSPORT CHAINCHAIN

The electron carriers The electron carriers NADHNADH and and FADHFADH22 transfer their electrons to the transfer their electrons to the electron transport chain.electron transport chain.

The electrons are passed through a The electrons are passed through a series of proteins, gradually releasing series of proteins, gradually releasing the energy they contain, to form the energy they contain, to form 32 32 ATPATP molecules. molecules.

The final electron acceptor is The final electron acceptor is oxygenoxygen..

Electron Transport Chain

Aerobic RespirationAerobic Respiration

Anaerobic RespirationAnaerobic Respiration(No oxygen)(No oxygen)

Lactic acid Lactic acid fermentation:fermentation: Occurs during Occurs during strenuous exercisestrenuous exercise when the body is not when the body is not able to supply needed able to supply needed oxygen to the muscles. oxygen to the muscles.

Allows the continued Allows the continued production of ATP until production of ATP until oxygen levels are oxygen levels are restoredrestored..

Anaerobic Respiration Anaerobic Respiration Cont...Cont...

No Oxygen!!!No Oxygen!!! Occurs in the Occurs in the cytoplasmcytoplasm of the of the

cell.cell. Produces lactic acid.Produces lactic acid.

Not very efficient – Only Not very efficient – Only 2 ATP2 ATP produced.produced.

Anaerobic Respiration Anaerobic Respiration Cont..Cont..

Alcoholic FermentationAlcoholic Fermentation

Used by yeast and some Used by yeast and some bacteria.bacteria.

Produces carbon dioxide and Produces carbon dioxide and alcohol.alcohol.

Cellular RespirationCellular Respiration

Cellular Respiration is the process that Cellular Respiration is the process that

releases energy by breaking down food releases energy by breaking down food

molecules in the presence of oxygen.molecules in the presence of oxygen.

6O6O22 + C + C66HH1212OO66 6CO 6CO22 + 6H + 6H22O + EnergyO + Energy

Oxygen + Glucose Oxygen + Glucose Carbon Dioxide + Carbon Dioxide +

Water + EnergyWater + Energy

Cellular RespirationCellular Respiration

KEY CONCEPT The overall process of cellular respiration converts sugar into ATP using oxygen.

Cellular respiration makes Cellular respiration makes ATP by breaking down ATP by breaking down

sugars.sugars. Cellular respiration is aerobic, or requires oxygen.Cellular respiration is aerobic, or requires oxygen. Aerobic stages take place in mitochondria.Aerobic stages take place in mitochondria.

mitochondrion

animal cell

Glycolysis must take place first.Glycolysis must take place first.

– anaerobic process (does not require oxygen)– takes place in cytoplasm– splits glucose into two three-carbon molecules– produces two ATP molecules

Cellular respiration is like Cellular respiration is like a mirror image of a mirror image of photosynthesis.photosynthesis. The Krebs cycle transfers energy to an The Krebs cycle transfers energy to an

electron transport chain.electron transport chain. takes place intakes place in

mitochondrial matrixmitochondrial matrix breaks down three-carbonbreaks down three-carbon

molecules from glycolysismolecules from glycolysis– makes a small amount of ATP– releases carbon dioxide– transfers energy-carrying

molecules6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

1

2

4

3

and

and

and

Krebs Cycle

6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

1

2

4

3

and

and

and

• The electron transport chain produces a large amount of ATP.

– takes place in inner membrane

– energy transferred to electron transport chain

– oxygen enters process– ATP produced

– water released as awaste product

Electron Transport

The equation for the overall process is:The equation for the overall process is:

CC66HH1212OO66 + 6O + 6O2 2 6CO 6CO22 + 6H + 6H22OO

• The reactants in photosynthesis are the same as the products of cellular respiration.

FermentationFermentation Releases energy from glucose without the Releases energy from glucose without the

presence of oxygen.presence of oxygen. There are two types of fermentation: There are two types of fermentation:

alcoholic and lactic acid.alcoholic and lactic acid. Alcoholic fermentation is done by yeasts Alcoholic fermentation is done by yeasts

and some microorganisms. It produces and some microorganisms. It produces alcohol & Carbon Dioxidealcohol & Carbon Dioxide

Lactic Acid is produced by muscles during Lactic Acid is produced by muscles during rapid exercise when the body cannot supply rapid exercise when the body cannot supply enough oxygen.enough oxygen.

Fermentation is used in food production.Fermentation is used in food production.

– yogurt

– cheese

– bread

Aerobic RespirationAerobic Respiration

1.1. Includes the Includes the Krebs Krebs CycleCycle & the & the Electron Electron Transport ChainTransport Chain

2.2. Pyruvic acid Pyruvic acid from from glycolysis diffuses into glycolysis diffuses into matrix of mitochondria matrix of mitochondria & reacts with coenzyme & reacts with coenzyme A to form A to form acetyl-CoA acetyl-CoA (2-(2-carbon compound)carbon compound)

3.3. COCO2 2 and NADHand NADH are also are also

producedproduced

Krebs CycleKrebs Cycle

Occurs in the matrix of the mitochondrionOccurs in the matrix of the mitochondrion

During the Krebs Cycle, pyruvic acid is During the Krebs Cycle, pyruvic acid is

broken down into carbon dioxide in a broken down into carbon dioxide in a

series of energy-extracting reactions.series of energy-extracting reactions.

Citric Acid is created in this cycle thus Citric Acid is created in this cycle thus

giving it the nickname Citric Acid cycle.giving it the nickname Citric Acid cycle.

Net ATP Production is 2 ATP.Net ATP Production is 2 ATP.

The Krebs cycle produces energy-carrying molecules.The Krebs cycle produces energy-carrying molecules.

Electron Transport ChainElectron Transport Chain

ReferencesReferences

This presentation is a mash up of 3 different sources. They This presentation is a mash up of 3 different sources. They are:are:Taylor, J.(2010). Unit 4 Chemical energy and ATP.Taylor, J.(2010). Unit 4 Chemical energy and ATP.http://www.slideshare.net/olympushighschool/unit-4-chemical-energy-and-atp

Accessed 6 March 2014Accessed 6 March 2014Distarasiswa, D. (2010). Cellular Respiration.Distarasiswa, D. (2010). Cellular Respiration.http://www.slideshare.net/dhitaunforgetable/powerpoint-metabolisme-2

Accessed 6 March Accessed 6 March Ferguson, S. (2009).Energy in a cell.Ferguson, S. (2009).Energy in a cell.http://www.slideshare.net/biologyteacher60/chapter-9-biology-iAccessed 6 March 2014