Cellular RespirationCellular Respiration

Cellular RespirationCellular Respiration

• An oxygen(O(O22)) requiring process that uses energyenergy extracted from organic molecules (glucose)organic molecules (glucose) to produce energy (ATP), COenergy (ATP), CO22 and water (Hwater (H22O).O).

C6H12O6 + 6O2 6CO2 + 6H2O + energy

glucoseglucose 36 ATP

Question:Question:

• In what kinds organisms does cellular In what kinds organisms does cellular respiration take place?respiration take place?

Plants and AnimalsPlants and Animals

• Plants - AutotrophsPlants - Autotrophs: self-producers.• Animals - Heterotrophs: consumers.

MitochondriaMitochondria

• OrganelleOrganelle where cellular respirationcellular respiration takes place.

Innermembrane

Outermembrane

Innermembrane space

MatrixCristae

Breakdown of Cellular RespirationBreakdown of Cellular Respiration

• 3 main parts (reactions).3 main parts (reactions).

1. Glycolysis (splitting of sugar)1. Glycolysis (splitting of sugar)

a. cytosol, just outside of mitochondria.

Breakdown of Cellular RespirationBreakdown of Cellular Respiration

2. Krebs Cycle (Citric Acid Cycle)2. Krebs Cycle (Citric Acid Cycle)

* occurs in mitochondrial matrix

3. Electron Transport Chain (ETC) 3. Electron Transport Chain (ETC) * inner mitochondrial membrane.

1. Glycolysis1. Glycolysis

• Occurs in the cytosol just outside of mitochondria.

• Two phases (10 steps):Two phases (10 steps):

A. Energy investment phase (2 ATP to start)A. Energy investment phase (2 ATP to start)

B. Energy yielding phaseB. Energy yielding phase

1. Glycolysis1. Glycolysis

A. Energy Investment Phase:A. Energy Investment Phase:

Glucose (6C)

Glyceraldehyde phosphate (2 - 3C) (G3P or GAP)

2 ATP - used0 ATP - produced0 NADH - produced

2ATP

2ADP + P

C-C-C-C-C-C

C-C-C C-C-C

1. Glycolysis1. Glycolysis

B. Energy Yielding PhaseB. Energy Yielding Phase

Glyceraldehyde phosphate (2 - 3C) (G3P or GAP)

Pyruvate (2 - 3C) (PYR)

0 ATP - used4 ATP - produced2 NADH - produced

4ATP

4ADP + P

Fermentation Fermentation

• Occurs in cytosol when “NO Oxygen”“NO Oxygen” is present (called anaerobic).(called anaerobic).

• Remember: glycolysisglycolysis is part of fermentationfermentation.

• Two Types:Two Types:

1.1. Alcoholic FermentationAlcoholic Fermentation

2. Lactic Acid Fermentation2. Lactic Acid Fermentation

Alcohol FermentationAlcohol Fermentation

• Plants and FungiPlants and Fungi beer and winebeer and wine

glucose

Glycolysis

CCCCCC

CCC

2 Pyruvic acid

2ATP2ATP2ADP+ 2

2NADH

P

2 NAD+

CC

2 Ethanol2 Ethanol2CO2CO22

releasedreleased

2NADH 2 NAD+

Makes bread rise!

Alcohol FermentationAlcohol Fermentation

• End Products: Alcohol fermentationEnd Products: Alcohol fermentation

2 - ATP (substrate-level phosphorylation)

2 - CO2

2 - Ethanol’s

Lactic Acid FermentationLactic Acid Fermentation

• Animals (pain in muscle after a workout).Animals (pain in muscle after a workout).

2 Lactic2 Lactic acidacid

2NADH 2 NAD+

CCC

Glucose

GlycolysisCCC

2 Pyruvic acid

2ATP2ATP2ADP+ 2

2NADH

P

2 NAD+

CCCCCC

Lactic Acid FermentationLactic Acid Fermentation

• End Products: Lactic acid fermentationEnd Products: Lactic acid fermentation

2 - ATP

2 - Lactic Acids (causes muscle fatigue)

2. Krebs Cycle (Citric Acid Cycle)2. Krebs Cycle (Citric Acid Cycle)

• Location:Location: mitochondrial matrix.

• It takes 2 turns of the krebs cycle to convert glucose molecule.

MitochondrialMatrix

Aerobic respiration (with oxygen) occurs in the mitochondria

2. Krebs Cycle (Citric Acid Cycle)2. Krebs Cycle (Citric Acid Cycle)

KrebsCycle

1 Acetyl CoA (2C)

3 NAD+

3 NADH3 NADHFAD

FADHFADH22

ATPATP ADP + P

(one turn)(one turn)

OAA (4C) Citrate (6C)

2 CO2

2. Krebs Cycle (Citric Acid Cycle)2. Krebs Cycle (Citric Acid Cycle)

KrebsCycle

2 Acetyl CoA (2C)

6 NAD+

6 NADH6 NADH2 FAD

2 FADH2 FADH22

2 ATP2 ATP 2 ADP + P

(two turns)(two turns)

OAA (4C)Citrate (6C)

4 CO2

2. Krebs Cycle (Citric Acid Cycle)2. Krebs Cycle (Citric Acid Cycle)

• Total net yield (2 turns2 turns of krebs cycle)

1. 2 - ATP (substrate-level phosphorylation)

2. H+ Carrier 6 – NADH

3. H+ Carrier 2 - FADH2

4. 4 - CO2

Summary: Some CO2, Lots of energy carriers, some ATP

3. Electron Transport Chain (ETC) and3. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Oxidative Phosphorylation (ChemiosmosisChemiosmosis))

• Location:Location: inner mitochondrial membrane.

• ETC pumps H+ (protons) across inner membrane (lowers pH in inner membrane space).

InnerMitochondrialMembrane

3. Electron Transport Chain (ETC)3. Electron Transport Chain (ETC)))

• The H+ then move via diffusiondiffusion (Proton Motive Force) through ATP Synthase to make ATP.

• Each NADH converts to 3 ATP.

• Each FADH2 converts to 2 ATP (enters the ETC at a lower level than NADH).

3. Electron Transport Chain (ETC)3. Electron Transport Chain (ETC)

Innermembrane

Outermembrane

Innermembrane space

MatrixCristae

The ETC produces most of the ATP during aerobic respiration

3. 3. ETC and Oxidative Phosphorylation ETC and Oxidative Phosphorylation ((Chemiosmosis for Chemiosmosis for NADHNADH))

NADH+ H+

ATPSynthase

1H+ 2H+ 3H+

higher Hhigher H++

concentrationconcentration

H+

ADP + ATP

lower Hlower H++

concentrationconcentration

H+

(Proton Pumping)

P

E T C

NAD+

2H+ + 1/2O2 H2O

Intermembrane SpaceIntermembrane Space

MatrixMatrix

InnerMitochondrialMembrane

3. 3. ETC ETC and and Oxidative Phosphorylation Oxidative Phosphorylation (Chemiosmosis for (Chemiosmosis for FADH2)

FADH2

+ H+

ATPSynthase

1H+ 2H+

higher Hhigher H++

concentrationconcentration

H+

ADP + ATP

lower Hlower H++

concentrationconcentration

H+

(Proton Pumping)

P

E T C

FAD+2H+ +

1/2O2

H2O

Intermembrane SpaceIntermembrane Space

MatrixMatrix

InnerMitochondrialMembrane

TOTAL ATP YIELDTOTAL ATP YIELD

1. 02 ATP - Glycolysis

2. 34 ATP – Kreb’s Cycle & ETC

36 ATP - TOTAL YIELD

ATPATP

Eukaryotes(Have Membranes)

• Total ATP Yield02 ATP - glycolysis (substrate-level phosphorylation)

04 ATP - converted from 2 NADH - glycolysis

06 ATP - converted from 2 NADH - grooming phase

02 ATP - Krebs cycle (substrate-level phosphorylation)

18 ATP - converted from 6 NADH - Krebs cycle

04 ATP - converted from 2 FADH2 - Krebs cycle

36 ATP - TOTAL

Maximum ATP Yield for Cellular Respiration (Eukaryotes)

36 ATP (maximum per glucose)

Glucose

Glycolysis

2ATP 4ATP 6ATP 18ATP 4ATP 2ATP

2 ATP(substrate-levelphosphorylation)

2NADH

2NADH

6NADH

KrebsCycle

2FADH2

2 ATP(substrate-levelphosphorylation)

2 Pyruvate

2 Acetyl CoA

ETC and Oxidative Phosphorylation

Cytosol

Mitochondria

Question:Question:

• In addition to glucose, what other various In addition to glucose, what other various food molecules are used in Cellular food molecules are used in Cellular Respiration?Respiration?

Catabolism of VariousCatabolism of VariousFood MoleculesFood Molecules

• Other organic molecules used for fuel.

1. Carbohydrates: polysaccharides

2. Fats: glycerol’s and fatty acids

3. Proteins: amino acids