Cellular RespirationCellular Respiration

Chemical Energy & FoodChemical Energy & Food

One gram of glucose = 3811 caloriesOne gram of glucose = 3811 calories

1 calorie = amount of energy needed 1 calorie = amount of energy needed to heat 1 gram of water 1 degree to heat 1 gram of water 1 degree CelsiusCelsius

Food calories are measured in Food calories are measured in Calories where 1 Calorie = 1000 Calories where 1 Calorie = 1000 calories.calories.

What is the difference?What is the difference?

CaloriesCalories

Cellular RespirationCellular Respiration

Cellular Respiration is the process Cellular Respiration is the process that releases energy by breaking that releases energy by breaking down food molecules in the presence down food molecules in the presence of oxygen.of oxygen.

6O6O22 + C + C66HH1212OO66 6CO 6CO22 + 6H + 6H22O + O + EnergyEnergy

Oxygen + Glucose Oxygen + Glucose Carbon Dioxide Carbon Dioxide + Water + Energy+ Water + Energy

ATPATP

Adenosine Triphosphate (ATP)—Adenosine Triphosphate (ATP)—usuable energy form in living thingsusuable energy form in living things

ATP is the important product of ATP is the important product of cellular respiration. cellular respiration.

3 Steps in Cellular Respiration3 Steps in Cellular Respiration

Glycolysis—happens in cytoplasmGlycolysis—happens in cytoplasm

Krebs Cycle—happens in Krebs Cycle—happens in mitochondriamitochondria

Electron Transport Chain—happens Electron Transport Chain—happens in mitochondriain mitochondria

Glycolysis--Step 1Glycolysis--Step 1Glycolysis is the process in which one Glycolysis is the process in which one molecule of glucose is broken in half, molecule of glucose is broken in half, producing two molecules of pyruvic acid (a producing two molecules of pyruvic acid (a 3 carbon compound).3 carbon compound).

2 ATP needed to start reaction, 4 ATP are 2 ATP needed to start reaction, 4 ATP are produced thus the net gain is 2 ATP.produced thus the net gain is 2 ATP.

Does NOT require oxygenDoes NOT require oxygen

Electron CarriersElectron Carriers

NADNAD+ + (nicotinamide adenine (nicotinamide adenine dinucleotide) is an electron carrier dinucleotide) is an electron carrier used during glycolysisused during glycolysis

When electrons are added to NADWhen electrons are added to NAD++ it it turns into NADH (which holds the turns into NADH (which holds the electrons until they are needed later electrons until they are needed later on in cellular respiration on in cellular respiration

The Krebs Cycle—Step 2The Krebs Cycle—Step 2

NEEDS OXYGENNEEDS OXYGEN

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 during the first Citric Acid is created during the first step of this cycle thus giving it the step of this cycle thus giving it the nickname Citric Acid cycle.nickname Citric Acid cycle.

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

Electron Carriers in KrebElectron Carriers in Kreb’’s s CycleCycle

NADNAD++

FAD (flavin adenine dinucleotide)FAD (flavin adenine dinucleotide)– When electrons are added to FAD it When electrons are added to FAD it

turns into FADHturns into FADH22

– Both NADH and FADHBoth NADH and FADH2 2 carry high energy carry high energy electrons to the electron transport chainelectrons to the electron transport chain

Electron Transport Chain—3Electron Transport Chain—3rdrd StepStep

The electron transport chain uses the high-The electron transport chain uses the high-energy electrons from the glycolysis and energy electrons from the glycolysis and KrebKreb’’s Cycle to convert ADP to ATP.s Cycle to convert ADP to ATP.

In eukaryotes, high energy electrons are In eukaryotes, high energy electrons are passed along the electron transport chain passed along the electron transport chain over a series of carrier proteins on the over a series of carrier proteins on the mitochondrial inner membranemitochondrial inner membrane

In prokaryotes this occurs on the cell In prokaryotes this occurs on the cell membranemembrane

Total ATP 32.Total ATP 32.

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

TotalsTotals

Gycolysis 2 ATPGycolysis 2 ATP

Krebs Cycle 2 ATPKrebs Cycle 2 ATP

Electron Transport Chain 32 ATPElectron Transport Chain 32 ATP

Total = 36 ATPTotal = 36 ATP

Energy & ExerciseEnergy & Exercise

Quick energyQuick energy – Lactic Acid – Lactic Acid fermentation is used to get quick fermentation is used to get quick energy and gives off lactic acid as a energy and gives off lactic acid as a by product, thus the muscle pain.by product, thus the muscle pain.

Respiration Odds and EndsRespiration Odds and Ends

Fermentation is less efficient than Fermentation is less efficient than aerobic respiration, but it is fasteraerobic respiration, but it is faster

Fermentation alone cannot keep you Fermentation alone cannot keep you alive for long.alive for long.

All fermentation (ethyl alcohol and All fermentation (ethyl alcohol and lactic acid) occurs in the cytoplasmlactic acid) occurs in the cytoplasm

Glycolysis is done by all organisms Glycolysis is done by all organisms on Earthon Earth

Odds and Ends Cont.Odds and Ends Cont.

COCO2 2 is the by-product of respiration. Not is the by-product of respiration. Not all energy in glucose is conereted to all energy in glucose is conereted to ATP, some is lost as heat.ATP, some is lost as heat.

Not all cells have the same number of Not all cells have the same number of mitochondria. Cells with high energy mitochondria. Cells with high energy needs have more. Cells with less don’t needs have more. Cells with less don’t do much work.do much work.

Muscles = lots (100’s or 1000’s)Muscles = lots (100’s or 1000’s)

Skin cells = fewSkin cells = few

Odds and Ends ContOdds and Ends Cont

Most of the energy produced by Most of the energy produced by aerobic respiration is produced by aerobic respiration is produced by the Electron Transport Chain step.the Electron Transport Chain step.

2 ATP’s are needed to start 2 ATP’s are needed to start respiration. These are called the respiration. These are called the activiation energy.activiation energy.

Comparing Photosynthesis & Comparing Photosynthesis & RespirationRespiration

PhotosynthesisPhotosynthesis Cellular Cellular RespirationRespiration

FunctionFunction Energy StorageEnergy Storage Energy Energy ReleaseRelease

LocationLocation ChloroplastsChloroplasts MitochondriaMitochondria

Reactants Reactants COCO22 and H and H22OO CC66HH1212OO66 and and OO22

ProductsProducts CC66HH1212OO66 and O and O22 COCO22 and H and H22OO

EquationEquation 6CO6CO22 + 6H + 6H22O O CC66HH1212OO66 + 6O + 6O22

CC66HH1212OO66 + 6O + 6O22

6CO6CO22 + 6H + 6H22OO