Chapter 9: Cellular Respiration Chapter 9: Cellular Respiration and Fermentationand Fermentation

Section 1:Section 1:

Cellular Respiration: An Cellular Respiration: An OverviewOverview

A. Chemical Energy and FoodA. Chemical Energy and FoodRespiration- Opposite of Respiration- Opposite of PhotosynthesisPhotosynthesis– Breaks down the food Breaks down the food we eat into ATP for we eat into ATP for cellular activity and cellular activity and maintenance of maintenance of homeostasishomeostasis– Energy conversion: Energy conversion: – Sun Sun Photosynthesis Photosynthesis Glucose-Glucose-RespirationRespirationEnergy for Energy for

ActivityActivity

Therefore-

Photosynthesis:

Sunlight + CO2+ H2O----------

C6H12O6 + 6O2

And……………..

Respiration:

C6H12O6 + 6O2------6CO2 + 6H20 +

ATP

Are energy conversions responsible for converting……..(Finish this statement )

B. Aerobic v Anaerobic RespirationB. Aerobic v Anaerobic RespirationRespiration is responsible for producing Respiration is responsible for producing energy for cellular activityenergy for cellular activityIt is much more efficient to break down It is much more efficient to break down food in order to liberate energy in the food in order to liberate energy in the presence of OXYGENpresence of OXYGEN

This means it is AEROBIC- with O2This means it is AEROBIC- with O2Some organisms live in ANOXIC Some organisms live in ANOXIC environments (Without Oxygen)environments (Without Oxygen)

These bacteria are known as These bacteria are known as OBLIGATE ANAEROBES-oxygen is OBLIGATE ANAEROBES-oxygen is

harmful to themharmful to them

Some anaerobes can survive for Some anaerobes can survive for short periods of time in the presence short periods of time in the presence of oxygen-of oxygen-

They are called Facultative They are called Facultative AnaerobesAnaerobes

ex- Brewer’s Yeastex- Brewer’s Yeast

Most Aerobes can survive for very Most Aerobes can survive for very short periods of time in low oxygen short periods of time in low oxygen conditionsconditions

People/Humans prefer to respire People/Humans prefer to respire aerobically- This is why we breathe!!aerobically- This is why we breathe!!From time to time we respire From time to time we respire anaerobically- like after intense anaerobically- like after intense exercise, like weight lifting and exercise, like weight lifting and sprinting- (This is why we are often sprinting- (This is why we are often out of breathe afterwards)out of breathe afterwards)When our bodies anaerobically When our bodies anaerobically respire for too long we get cramps respire for too long we get cramps due to build up of lactic aciddue to build up of lactic acidThis does damage to tissue and will This does damage to tissue and will not sustain us for longnot sustain us for long

C. Glycolysis!C. Glycolysis!Both Aerobic and Anaerobic Both Aerobic and Anaerobic Respiration begin with Glycolysis!!Respiration begin with Glycolysis!!

Glycolysis- breakdown of GlucoseGlycolysis- breakdown of Glucose

When Glucose is broken down it When Glucose is broken down it becomes a three Carbon molecule becomes a three Carbon molecule called Pyruvate a.k.a Pyruvic Acidcalled Pyruvate a.k.a Pyruvic Acid

• This takes place in the cytoplasm This takes place in the cytoplasm (outside the Mitochondria)(outside the Mitochondria)

Glycolysis

2 Phases:

Energy Investment (It takes money to make money)

Initial Cost of 2 ATP in order to break apart glucose

Energy Payoff- By breaking down glucose we form 4 ATP

Net Gain of 2 ATP

Glycolysis

Inputs of Glycolysis:Inputs of Glycolysis: Glucose- all food is broken down Glucose- all food is broken down

through digestion into simple through digestion into simple sugars sugars such as glucosesuch as glucose

ATP- Initial Energyto break apart ATP- Initial Energyto break apart glucose into PGAL- Two 3 Carbon glucose into PGAL- Two 3 Carbon

IntermediatesIntermediates

• Outputs of GlycolysisOutputs of GlycolysisATP- 2 ATP Molecules are producedATP- 2 ATP Molecules are producedTwo molecules of Pyruvate- Pyruvic AcidTwo molecules of Pyruvate- Pyruvic Acid

2 Molecules of NADH- Electron carriers2 Molecules of NADH- Electron carriers

Glycolysis

Glycolysis

The Fate of Pyruvic Acid depends on The Fate of Pyruvic Acid depends on the presence of Oxygenthe presence of Oxygen– If O2 is present Aerobic Respiration If O2 is present Aerobic Respiration

occurs aka Respiration occurs aka Respiration – If O2 absent- Anaerobic Repiration If O2 absent- Anaerobic Repiration

occurs- aka Fermentationoccurs- aka Fermentation

D. Aerobic Cellular RepirationD. Aerobic Cellular RepirationHappens in the Presence of OxygenHappens in the Presence of OxygenBegins with the products of Glycolysis: two Begins with the products of Glycolysis: two molecules of Pyruvic Acid (C-C-C)molecules of Pyruvic Acid (C-C-C)

The Pyruvic Acid diffuses into the Mitochondrial The Pyruvic Acid diffuses into the Mitochondrial Matrix and enters the Citric Acid Cycle- aka Matrix and enters the Citric Acid Cycle- aka Kreb’s CycleKreb’s Cycle- In the CAC Pyruvic Acid is broken apart, one - In the CAC Pyruvic Acid is broken apart, one Carbon at a time and released as CO2Carbon at a time and released as CO2- As it is broken energy is converted (2ADP- - As it is broken energy is converted (2ADP- 2ATP)2ATP)

and electron energy is stored (4NAD+---and electron energy is stored (4NAD+---4NADH and FAD+ ----FADH)4NADH and FAD+ ----FADH)

- This happens twice ( 8 NADH and 2 FADH - This happens twice ( 8 NADH and 2 FADH Total- that is 20 Electrons)Total- that is 20 Electrons)

1. Citric Acid Cycle1. Citric Acid Cyclea. Begins with Pyruvic Acid (C-C-C)a. Begins with Pyruvic Acid (C-C-C)b.b. Enzymes remove 1 Enzymes remove 1

Carbon- leaving behindCarbon- leaving behind a two carbon a two carbon compound calledcompound called Acetyl/Acetic AcidAcetyl/Acetic Acid

c.c. This joins with anotherThis joins with anotherenzyme (Co A) which enzyme (Co A) which is 4 Carbons Long!is 4 Carbons Long!Becomes Acetyl Co ABecomes Acetyl Co A

(6 Carbons)(6 Carbons)

This makes it easier to separate the last two carbons This makes it easier to separate the last two carbons from Pyruvic Acid and expel them as CO2 while from Pyruvic Acid and expel them as CO2 while stealing their energy in the form of electrons- Lots of stealing their energy in the form of electrons- Lots of NADH and FADHNADH and FADH

Citric Acid CycleCitric Acid Cycle

Remember- this happens twice!!! Glucose was broken down into two mols of Pyruvic Acid!

Total ATP= 2

Total electron Pairs= 10

Every time a Carbon is removed- 2 High Energy Electrons are Freed and stored by NAD and FAD

Citric Acid CycleCitric Acid Cycle

Inputs: 2 Pyruvic Acids (Glycolysis)Inputs: 2 Pyruvic Acids (Glycolysis)

Outputs: CO2 (Expelled as waste)Outputs: CO2 (Expelled as waste)

2 ATP (very little energy- 2 ATP (very little energy- used for cellular activity)used for cellular activity)

NADH and FADH (To be NADH and FADH (To be used later in order to used later in order to make a lot of ATP) make a lot of ATP)

All of these electrons are going to be used during the next phase (Electron

Transport) to synthesize ATP

2.2. Electron Transport Chain (ETC)Electron Transport Chain (ETC)a.a. Electrons carried to the innerElectrons carried to the inner membrane by NADH and FADHmembrane by NADH and FADH are dropped off at the beginningare dropped off at the beginningb.b. As the electrons are passed As the electrons are passed

along, their energy is used to along, their energy is used to pump H+ ions out of the matrix pump H+ ions out of the matrix and into the intermembrane spaceand into the intermembrane space

creating a Conc. Gradientcreating a Conc. Gradientc.c. The only way back into the matrix for H+ ions is through a The only way back into the matrix for H+ ions is through a

protein called ATP Synthase. protein called ATP Synthase. d.d. As H+ move through ATP Synthase like water through a dam, As H+ move through ATP Synthase like water through a dam,

energy is used to convert ADP to ATP.energy is used to convert ADP to ATP.e.e. Each pair of electrons can produce between two and three ATPs Each pair of electrons can produce between two and three ATPs

(Depends on if they came from NADH or FADH)(Depends on if they came from NADH or FADH)f.f. 9NADH= 28 ATP 9NADH= 28 ATP

2FADH= 4 ATP2FADH= 4 ATPTotal of 32 ATPs created during ETC!!!!Total of 32 ATPs created during ETC!!!!

Electron Transport Chain Electron Transport Chain and ATP Synthaseand ATP Synthase

Total ATP ProductionTotal ATP Production

Glycolysis- 2 ATPGlycolysis- 2 ATP

Citric Acid Cycle- 2ATPCitric Acid Cycle- 2ATP

Electron Transport-32 ATPElectron Transport-32 ATP

TOTAL= 36 ATPTOTAL= 36 ATP

Not bad for one molecule of glucose!!Not bad for one molecule of glucose!!

D. Anaerobic RespirationD. Anaerobic RespirationOccurs without Oxygen PresentOccurs without Oxygen Present

Also known as “Fermentation”Also known as “Fermentation”

TequilaBeer Whiskey

What do they all have in common? (Three Things)

Cramping

Fermentation

FermentationFermentation1. Alcoholic Fermentation:1. Alcoholic Fermentation:

a. Occurs in Yeast when Oxygen is not present to clear the ETC and CAC Cycle

b. Electrons cannot be passed into Kreb’s cycle so they get passed back to Pyruvic Acid

c. Forms new products Ethyl Alcohol and Carbon Dioxide

Alcoholic FermentationAlcoholic Fermentation

Pyruvic AcidEthyl Alcohol

Carbon Dioxide

Count the Atoms- What goes in should come out!!!!

=

2. Lactic Acid Fermentation2. Lactic Acid Fermentation

a. Occurs in all animal species

b. When Oxygen is not present- electrons get passed back to Pyruvic acid and attach in a different location (Look at H’s)- Forms Lactic Acid

c. Responsible for muscle soreness and cramping

Lactic Acid FermentationLactic Acid Fermentation

Pyruvic Acid

=