Oxidative Phosphorylation

Oxidative Phosphorylation

Step 3

OverviewThe spatial arrangement of electron

carriers built into the inner membrane makes it possible for the mitochondrion to use chemical energy released by redox reactions to create an H+ gradient and then use the energy stored in that gradient to drive ATP synthase.

Occurs across the inner membrane (cristae)

Produces up to 34 ATP

6.10 Most ATP production occurs by oxidative phosphorylation

Electrons from NADH and FADH2 Travel down the electron transport chain to

oxygen, which picks up H+ to form water NADH is oxidized as the first protein complex is

reduced FADH2 is oxidized while the first electron carrier

is reduced.

Energy released by the redox reactions Is used to pump H+ into the space between the

mitochondrial membranes (active transport)

In chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes

Driving the synthesis of ATP TURBINE

Intermembrane space

Inner mitochondrial membrane

Mitochondrial matrix

Protein complex

Electron flow

Electron carrier

NADH NAD+

FADH2 FAD

H2OATPADP

ATP synthase

H+ H+ H+H+

H+ H+

H+H+

H+

H+

H+

H+

H+

H+

+ P

O2

Electron Transport Chain Chemiosmosis

.

OXIDATIVE PHOSPHORYLATION

+ 212

ATPSynthase

Turbine

The Final AcceptorOne oxygen atom will accept two

electrons and form water with two hydrogen.

Overall Video

CH 25

ATPSynthase

Turbine

Oxidative Phosphorylationin four steps

1. Electron carrying molecules release e- NADH protein complex 1 FADH2 electron carrier 1

2. H+ ions from matrix are actively transported by pumps across the membrane into the inter membrane space.

3. e- are transported to Oxygen to form water

4. Chemiosmosis allows H+ ions to diffuse through ATP synthase in order to create ATP

CONNECTION6.11 Certain poisons interrupt critical events in cellular respiration

Various poisons Block the movement of electrons Block the flow of H+ through ATP synthase Allow H+ to leak through the membrane

H+

H+

H+

H+

H+

H+ H+ H+ H+

H+

H+

H+H+

O2

H2O P ATP

NADH NAD+

FADH2 FAD

Rotenone Cyanide, carbon monoxide

Oligomycin

DNP

ATPSynthase

+2

ADP+

Electron Transport Chain Chemiosmosis

12

Figure 6.11

Review CREach molecule of glucose yields up to 38 molecules of ATP

Each NADH molecule produces 3 ATPEach FADH2 molecule produces 2 ATP

Total10 NADH =302 FADH2 =4

4 ATP produced in steps 1 and 2

38

Fermentation: Anaerobic Respiration Under anaerobic conditions, many kinds of cells Can use

glycolysis alone to produce small amounts of ATP

In lactic acid fermentation NADH is oxidized to NAD+ as pyruvate is reduced to

lactate

2 Lactate

NAD+ NADH NADH NAD+2 2 22

2 ATP2 ADP + 22 Pyruvate

GLYCOLYSIS

P

Glucose

Figure 6.13A

In alcohol fermentation NADH is oxidized to NAD+ while converting

pyruvate to CO2 and ethanol

NAD+ NADH NADH NAD+2 2 2 2

GLYCOLYSIS

2 ADP + 2 P ATPGlucose 2 Pyruvate

releasedCO2

2 Ethanol22

Figure 6.13B

Figure 6.13C

Two Types of Fermenting OrganismsStrict anaerobesFacultative Anaerobes

INTERCONNECTIONS BETWEEN MOLECULAR BREAKDOWN AND SYNTHESIS

6.14 Cells use many kinds of organic molecules as fuel for cellular respiration

Carbohydrates, fats, and proteins can all fuel cellular respiration

When they are converted to molecules that enter glycolysis or the citric acid cycle

OXIDATIVEPHOSPHORYLATION(Electron Transportand Chemiosmosis)

Food, such aspeanuts

Carbohydrates Fats Proteins

Sugars Glycerol Fatty acids Amino acidsAminogroups

Glucose G3P Pyruvate AcetylCoA

CITRICACID

CYCLE

ATP

GLYCOLYSIS

Figure 6.14

EX: fats G3P and 2 carbon intermediates

6.15 Food molecules provide raw materials for biosynthesis

Cells use some food molecules and intermediates from glycolysis and the citric acid cycle as raw materials to make the 3 classes of macromolecules our cells need to function

This CONSUMES ATP

ATP needed to drive biosynthesis

ATP

CITRICACID

CYCLE

GLUCOSE SYNTHESISAcetylCoA Pyruvate G3P Glucose

Aminogroups

Amino acids Fatty acids Glycerol Sugars

CarbohydratesFatsProteins

Cells, tissues, organisms

Figure 6.15

6.16 The fuel for respiration ultimately comes from photosynthesis

All organisms Can harvest energy from organic molecules

Plants, but not animals Can also make these molecules from

inorganic sources by the process of photosynthesis

Figure 6.16