Cellular Respiration OverviewCellular Respiration OverviewCellular Respiration song to the Cellular Respiration song to the

tune of Californication =)tune of Californication =)

..\..\Biology 11-12\Bio videos\Cellular Respiration.mp4

Cellular RespirationCellular Respiration

Aerobic Cellular RespirationAerobic Cellular Respiration occurs in the occurs in the presence of oxygen in the cytosol and the presence of oxygen in the cytosol and the mitochondriamitochondriaThe process can be summarized as:The process can be summarized as:

CC66HH1212OO66 + 6O + 6O22 6CO 6CO22 + 6H + 6H22O + Energy O + Energy (ATP and Heat) (ATP and Heat)

Redox ReactionRedox Reaction

Redox ReactionsRedox Reactions – Reactions involving – Reactions involving the transfer of electronsthe transfer of electronsOxidationOxidation – When a substance loses – When a substance loses electrons in a redox reactionelectrons in a redox reaction– The substanceThe substance acceptingaccepting the electron is the electron is

known as the known as the oxidizing agentoxidizing agent

ReductionReduction – When a substance gains – When a substance gains electrons in a redox reactionelectrons in a redox reaction– The substance The substance donatingdonating the electron is known the electron is known

as the as the reducing agentreducing agent

Example: Sodium ChlorideExample: Sodium Chloride

Becomes Oxidized (loses electron)

Becomes Reduced (gains electron)

Oxidizing

Agent

Reducing

Agent

Production of ATPProduction of ATP

Becomes Oxidized

Becomes Reduced

Reducing

Agent

Oxidizing

Agent

Overview of the ProcessOverview of the Process

With oxygen present, there are With oxygen present, there are 33 main main steps in cellular respiration:steps in cellular respiration:

1.1. GlycolysisGlycolysis

2.2. The Citric Acid Cycle (Krebs Cycle)The Citric Acid Cycle (Krebs Cycle)

3.3. Oxidative PhosphorylationOxidative Phosphorylationa.a. ETC ETC

b.b. chemiosmosischemiosmosis

GlucoseGlycolysis Pyruvate

Oxidative Phosphorylation:

ETC And

Chemiosmosis

NADH and FADH2

NADH

ATP ATP ATP

Types of PhosphorylationTypes of Phosphorylation

Phosphorylation is how ATPs are formedPhosphorylation is how ATPs are formed

Oxidative PhosphorylationOxidative Phosphorylation – Phosphates – Phosphates added to ADP via the redox reactions in the added to ADP via the redox reactions in the ETCETC

Substrate Level PhosphorylationSubstrate Level Phosphorylation – An – An enzyme transfers a phosphate from a enzyme transfers a phosphate from a substrate, to ADP (glycolysis and citric acid substrate, to ADP (glycolysis and citric acid cycle)cycle)

GlycolysisGlycolysisGlycoGlyco=Sugar; =Sugar; LysisLysis= Split= Split

In Gylcolysis, Glucose is split into two 3-carbon In Gylcolysis, Glucose is split into two 3-carbon pyruvate pyruvate (pyruvic acid) molecules(pyruvic acid) molecules

In order to begin, glycolysis requires the input In order to begin, glycolysis requires the input of energy (ATP)of energy (ATP)

Glycolysis occurs in the cytosolGlycolysis occurs in the cytosol

Lets look at Glycolysis in a very simple form:Lets look at Glycolysis in a very simple form:

Glycolysis (Simplified)Glycolysis (Simplified)1.1. 2 ATP 2 ATP are are addedadded in the presences of glucose in the presences of glucose

2.2. 2 NADH 2 NADH are are producedproduced

3.3. 4 ATP 4 ATP are are producedproduced (Net gain of 2) (Net gain of 2)

4.4. 2 Pyruvate 2 Pyruvate molecules are molecules are formedformed

C C C C C C

C C C

C C C

C C C

C C C

Glucose

Pyruvic Acid

2ATP

2 ADP

4 ADP

4ATP

2 NAD+

2 NADH

Citric Acid CycleCitric Acid Cycle

Also referred to as the Also referred to as the Krebs CycleKrebs Cycle

Takes place in the matrixTakes place in the matrix

When oxygen is present, When oxygen is present, the Citric Acid Cycle the Citric Acid Cycle follows Glycolysisfollows Glycolysis

This cycle takes pyruvate This cycle takes pyruvate from glycolysis to make from glycolysis to make ATP, NADH, and FADHATP, NADH, and FADH22

Citric Acid Cycle SimplifiedCitric Acid Cycle Simplified

Pyruvate turns into acetyl CoA via Pyruvate turns into acetyl CoA via coenzyme A (CoA) (this is the link coenzyme A (CoA) (this is the link between glycolysis and the Citric Acid between glycolysis and the Citric Acid Cycle)Cycle)Acetyl CoA enters the Citric Acid Cycle Acetyl CoA enters the Citric Acid Cycle and is then transformed into citrate and is then transformed into citrate There are 7 intermediate molecules, until There are 7 intermediate molecules, until Oxaloacetate is reformed to begin the Oxaloacetate is reformed to begin the cycle againcycle again

Citric Acid Cycle - ProductsCitric Acid Cycle - Products

3 NADH, 1 FADH2, 1ATP, and CO3 NADH, 1 FADH2, 1ATP, and CO22 are are

produced in the Citric Acid Cycleproduced in the Citric Acid Cycle– Each NADH will generate about 3 ATPEach NADH will generate about 3 ATP

– FADHFADH22 will generate about 2 ATP will generate about 2 ATP

The COThe CO22 released from this cycle is the same released from this cycle is the same

COCO22 that you exhale while breathing that you exhale while breathing

Oxidative PhosphorylationOxidative Phosphorylation

This is the process of extracting This is the process of extracting ATP form the energy in NADH ATP form the energy in NADH and FADHand FADH22

Occurs in the cristae of the Occurs in the cristae of the mitochondriamitochondria

The electrons are passed The electrons are passed through an ETC to release ATPthrough an ETC to release ATP

The final electron acceptor is The final electron acceptor is oxygenoxygen

Oxygen bonds with 2 electrons Oxygen bonds with 2 electrons (carried by Hydrogen) to produce (carried by Hydrogen) to produce waterwater

e-e-

ADP

ADP

ADP

ADP

ATP

ATP

ATP

ATP

OH H

TotalsTotals

GlycolysisKrebs

CycleETC

+2 ATP + 2 ATP + 32 ATP = 36 ATP

Anaerobic EnvironmentsAnaerobic Environments

When no oxygen is present, the cell will When no oxygen is present, the cell will have to do one of two things:have to do one of two things:– Die due to the fact that there is no Oxygen to Die due to the fact that there is no Oxygen to

accept electrons at the end of oxidative, so no accept electrons at the end of oxidative, so no more NAD+ are mademore NAD+ are made

oror– They can undergo Fermentation:They can undergo Fermentation:

Lactic AcidLactic Acid

AlcoholicAlcoholic

FermentationFermentation

Takes place in the mitochondrial inner Takes place in the mitochondrial inner membranemembrane

Does not require oxygen to occurDoes not require oxygen to occur

Does not directly produce ATPDoes not directly produce ATP

Lactic Acid FermentationLactic Acid Fermentation

Pyruvate comes from glycolysis and is Pyruvate comes from glycolysis and is turned into lactate (lactic acid)turned into lactate (lactic acid)

NADH gives an electron to become NAD+NADH gives an electron to become NAD+

Alcoholic FermentationAlcoholic Fermentation

Pyruvate comes from glycolysis, and is Pyruvate comes from glycolysis, and is changed into acetaldehyde, and a COchanged into acetaldehyde, and a CO22 is is

given off in the processgiven off in the process

Acetaldehyde is turned into ethanol with Acetaldehyde is turned into ethanol with the help of an electron from NADHthe help of an electron from NADH

The products are COThe products are CO22, Ethanol, and NAD+, Ethanol, and NAD+

Why fermentation?Why fermentation?

Why do cells switch to fermentation?Why do cells switch to fermentation?

Why can’t cells use glycolysis and the Why can’t cells use glycolysis and the Krebs cycle in an anaerobic environment?Krebs cycle in an anaerobic environment?

Right now with your table compare and Right now with your table compare and contrast aerobic and anaerobic respirationcontrast aerobic and anaerobic respiration

Begin work on dynamic models

Work with the group you are assignedRead through the assignmentDesign your modelDivide up the workAnd begin!

Oh, and be ready for a short quiz tomorrow on the overview of cellular respiration.

Cellular Respiration – A Cellular Respiration – A Review of the ProcessReview of the Process

Test your knowledge and complete the graphic Test your knowledge and complete the graphic organizer without looking at your notes/book/etc.!organizer without looking at your notes/book/etc.!

Work independently =) Work independently =)

You have 10 minutes, turn in to the HW folder when You have 10 minutes, turn in to the HW folder when done. We will correct in class.done. We will correct in class.

GlycolysisGlycolysis

Breaks down glucose into pyruvic acidBreaks down glucose into pyruvic acid– 2 ATP are added2 ATP are added– 2 NADH are produced by NAD+ accepting 2 2 NADH are produced by NAD+ accepting 2

electronselectrons– 4 ATP are produced (yielding a net gain of 2 ATP)4 ATP are produced (yielding a net gain of 2 ATP)– 2 Pyruvic acid molecules are formed2 Pyruvic acid molecules are formed

**There are 9 intermediate molecules between glucose **There are 9 intermediate molecules between glucose and pyruvate**and pyruvate**

Krebs Cycle (Citric Acid Cycle)Krebs Cycle (Citric Acid Cycle)Before the actual cycle begins, pyruvate Before the actual cycle begins, pyruvate combines with coenzyme A (CoA) to produce a combines with coenzyme A (CoA) to produce a molecule called acetyl CoAmolecule called acetyl CoA– 1 NADH and 1 CO1 NADH and 1 CO22 is produced is produced

The first actual step of the Krebs Cycle is when The first actual step of the Krebs Cycle is when oxaloacetate combines with acetyl CoA to oxaloacetate combines with acetyl CoA to make citric acidmake citric acid

Products: 3 NADH, 1 FADHProducts: 3 NADH, 1 FADH22, 1 ATP 2CO, 1 ATP 2CO22 (this (this

is the COis the CO22 that we exhale) that we exhale)

Oxidative PhosphorylationOxidative PhosphorylationThe process of extracting ATP from NADH and The process of extracting ATP from NADH and FADHFADH22

Electrons from the carriers are passed down an Electrons from the carriers are passed down an ETCETC

The electrons final acceptor is an Oxygen The electrons final acceptor is an Oxygen molecule, and water is formed as a byproductmolecule, and water is formed as a byproduct

NADH can produce 3 ATPNADH can produce 3 ATP

FADHFADH22 can produce 2 ATP can produce 2 ATP

Chemiosmotic PhosphorylationChemiosmotic PhosphorylationWhen the electrons lose energy in O.P. it is used for When the electrons lose energy in O.P. it is used for chemiosmotic phosphorylationchemiosmotic phosphorylation

As the carriers move through the ETC, H+ are pumped from As the carriers move through the ETC, H+ are pumped from the matrix, across the cristae, and into the outer the matrix, across the cristae, and into the outer compartment creating a proton gradient (Potential Energy compartment creating a proton gradient (Potential Energy Reservoir)Reservoir)

Channel proteins (ATP Synthase) in the cristae allow the Channel proteins (ATP Synthase) in the cristae allow the protons to flow through and use the energy to produce ATP protons to flow through and use the energy to produce ATP from ADPfrom ADP

2 Types of Phosphorylation2 Types of PhosphorylationSubstrate LevelSubstrate Level – Occurs when a phosphate – Occurs when a phosphate group and its energy is transferred to ADP to group and its energy is transferred to ADP to form ATP. The substrate molecule donates the form ATP. The substrate molecule donates the phosphate (occurs in glycolysis)phosphate (occurs in glycolysis)

Oxidative PhosphorylationOxidative Phosphorylation – Occurs when – Occurs when phosphate is transferred but not the energy. phosphate is transferred but not the energy. Energy is provided from electrons in the ETCEnergy is provided from electrons in the ETC

Alcoholic FermentationAlcoholic FermentationPyruvic Acid is converted into acetaldehydePyruvic Acid is converted into acetaldehyde– 1 CO1 CO22 and 1 acetaldehyde is produced and 1 acetaldehyde is produced

Acetaldehyde is converted into ethanolAcetaldehyde is converted into ethanol– 1 ethanol is produced, and 1 NAD+ is produce 1 ethanol is produced, and 1 NAD+ is produce

The entire point of this process is to send NAD+ The entire point of this process is to send NAD+ back to glycolysis to keep slowly producing back to glycolysis to keep slowly producing ATP ATP

Lactic Acid FermentationLactic Acid Fermentation

Pyruvic Acid is converted to lactic acid Pyruvic Acid is converted to lactic acid – NAD+ is given off and sent back to glycolysisNAD+ is given off and sent back to glycolysis

Energy and ExerciseEnergy and Exercise

Energy in HumansEnergy in Humans

What sort of activities cause you to use What sort of activities cause you to use more energy?more energy?– Lets look at runningLets look at running

Human BodyHuman Body

The human body has a limited amount of The human body has a limited amount of ATP stored in itATP stored in it

The reserve can last about 90 seconds of The reserve can last about 90 seconds of intense exercise (like sprinting)intense exercise (like sprinting)

What does this mean?What does this mean?

Intense ExerciseIntense Exercise

Your body has 3 sources of ATPYour body has 3 sources of ATP– Stored ATPStored ATP– ATP’s from fermentationATP’s from fermentation– ATP’s from cellular respirationATP’s from cellular respiration

The stored ATP will only last about 30-40 The stored ATP will only last about 30-40 secondsseconds

After that we begin to undergo lactic acid After that we begin to undergo lactic acid fermentationfermentation

Lactic Acid FermentationLactic Acid FermentationWe can use the ATP’s in lactic acid We can use the ATP’s in lactic acid fermentation for about 90 secondsfermentation for about 90 seconds– What builds up in our muscles when this What builds up in our muscles when this

happens?happens?– Lactic Acid Lactic Acid

The only way to break down and get rid of The only way to break down and get rid of lactic acid is by using oxygenlactic acid is by using oxygen

Post SprintPost SprintWhy do runners breath heavily after a Why do runners breath heavily after a race?race?

Runners breathe heavily after a race to get Runners breathe heavily after a race to get oxygen to our muscles to break down oxygen to our muscles to break down lactic acidlactic acid

Running a MileRunning a Mile

We have just said that we can only We have just said that we can only generate ATP with lactic acid fermentation generate ATP with lactic acid fermentation for about 90 seconds.for about 90 seconds.

What if you were running a mile?What if you were running a mile?

Long Term EnergyLong Term Energy

Lactic Acid releases energy very quickly Lactic Acid releases energy very quickly (but can only last a short time)(but can only last a short time)When running a mile or more, your body When running a mile or more, your body will switch over to cellular respiration will switch over to cellular respiration (instead of fermentation)(instead of fermentation)Cellular respiration releases energy much Cellular respiration releases energy much more slowlymore slowlyThis is why athletes must pace themselves This is why athletes must pace themselves during a raceduring a race

Energy SourcesEnergy Sources

The body stores energy in a carbohydrate The body stores energy in a carbohydrate known as glycogenknown as glycogen

After 15-20 minutes of physical activity, After 15-20 minutes of physical activity, the body will use other sources for energythe body will use other sources for energy– FatsFats– ProteinsProteins