Cellular Respiration Part II: Glycolysis. Curriculum Framework f. Cellular respiration in eukaryotes...

Cellular Respiration Part II:Glycolysis

Curriculum Framework

• f. Cellular respiration in eukaryotes involves a series of coordinated enzyme-catalyzed reactions that harvest free energy from simple carbohydrates.

2

Big Energy Events of Respiration

– Glycolysis (breaks down glucose into two molecules of pyruvate)

– The citric acid cycle (completes the breakdown of glucose)

– Oxidative phosphorylation (accounts for most of the ATP synthesis)

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

Citricacidcycle

Pyruvateoxidation

Acetyl CoA

Glycolysis

Glucose Pyruvate

CYTOSOL MITOCHONDRION

ATP ATP

Substrate-levelphosphorylation

Substrate-levelphosphorylation

Big Energy Events of Respiration

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

Citricacidcycle

Pyruvateoxidation

Acetyl CoA

Glycolysis

Glucose Pyruvate

Oxidativephosphorylation:electron transport

andchemiosmosis

CYTOSOL MITOCHONDRION

ATP ATP ATP

Substrate-levelphosphorylation

Substrate-levelphosphorylation

Oxidative phosphorylation

Mitochondrion

Fuel (glucose)

Oxygen

Water

Carbondioxide

ATP

Curriculum Framework

GLYCOLYSIS2.F.1 Glycolysis rearranges the bonds in glucose molecules, releasing free energy to form ATP from ADP and inorganic phosphate, and resulting in the production of pyruvate.

7

Glycolysis• Glycolysis is thought to be one of the oldest

metabolic pathways.• This energy harvesting process occurs in the

cytoplasm of both prokaryotic and eukaryotic cells.

8

GlucoseATPMitochondrion

11

Glycolysis

Glycolysis harvests chemical energy by oxidizing glucose to pyruvate

• Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate

• Glycolysis occurs in the cytoplasm and has two major phases

– Energy investment phase– Energy payoff phase

• Glycolysis occurs whether or not O2 is present

Electron carrier (NADH)

ATP Pyruvic acid

Glycolysis

• Activation energy input• Splitting the fructose• Harvesting the energy

–2 NADH + H+, 2 ATP–Two pyruvates (pyruvic acid)

16

Substrate

Product

ADP

PATP

Enzyme Enzyme

Substrate-Level Phosphorylation

Inputs Outputs

GlucoseGlycolysis

2 Pyruvate 2 ATP 2 NADH

Curriculum Framework

2.F.2. Pyruvate is transported from the cytoplasm to the mitochondrion, where further oxidation occurs.

19

What happens to the pyruvate?

Oxidation of Pyruvate to Acetyl CoA

• Before the citric acid cycle can begin, pyruvate must be converted to acetyl Coenzyme A (acetyl CoA), which links glycolysis to the citric acid cycle

• This step is carried out by a multienzyme complex that catalyzes three reactions

Pyruvic acidOuter mitochondrial membrane

Inner mitochondrial membrane

Carbon dioxide

Electron carrier (NADH)

Acetyl CoA

Pyruvate

Transport protein

CYTOSOL

MITOCHONDRION

CO2 Coenzyme A

NAD + HNADH Acetyl CoA

1

2

3

Figure 9.6-3

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

Citricacidcycle

Pyruvateoxidation

Acetyl CoA

Glycolysis

Glucose Pyruvate

Oxidativephosphorylation:electron transport

andchemiosmosis

CYTOSOL MITOCHONDRION

ATP ATP ATP

Substrate-levelphosphorylation

Substrate-levelphosphorylation

Oxidative phosphorylation

Closing thoughts…

• What process is represented by A?

• What process is represented by B?

• C and D are products of A. What could they represent?

• What process is occurring at B?

• What does E represent?• What is the fate of E?

29

Created by:

Debra RichardsCoordinator of Secondary Science ProgramsBryan ISDBryan, TX