4.4 Overview of Cellular Respiration. Cellular Respiration… Is a process that makes ATP by breaking down sugars (glucose). Cellular respiration is aerobic,

4.4 Overview of Cellular Respiration

Cellular Respiration…• Is a process that makes ATP by

breaking down sugars (glucose).• Cellular respiration is aerobic, or

requires oxygen.

• Three Stages:1.Glycolysis

2.Krebs Cycle3.Electron Transport Chain

Cellular respiration takes place in the mitochondria!!!

Step 1: GLYCOLYSIS

• MUST happen FIRST…REQUIRED for Cellular Respiration.

• Anaerobic process (does NOT require oxygen)

• Takes place in cytoplasm• Enzymes split glucose into two

three-carbon molecules– Pyruvic Acid

• Produces two ATP molecules

Step 2: The Krebs Cycle

• Is the first main part of cellular respiration.

• Produces molecules that carry energy to the second part of cellular respiration.

Stage 2: KREBS CYCLE(Aerobic Pathway)

– takes place in the matrix of the mitochondria

– breaks down three-carbon molecules from glycolysis (Pyruvic Acid molecules)

– Regulated by enzymes– Makes 2 molecules of ATP– Releases carbon dioxide– Transfers energy-carrying molecules to

Electron Transport Chain• NADH & FADH2

6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

2

4

3

and

and

and

Step 3: The Electron Transport Chain

• Second main part of Cellular Respiration

• takes place in the inner membrane of the mitochondria

• Uses energy from Krebs Cycle to drive electron transport chain

• Oxygen enters process• 32-34 molecules of ATP produced• water released as a waste product• Formed when enzyme combines hydrogen and

oxygen

6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

1

2

4

3

and

and

and

Products of Cellular Respiration-including Glycolysis

• 6 molecules Carbon dioxide from the Krebs cycle and Glycolysis

• 6 molecules of water from the electron transport chain

• A net gain of up to 38 ATP molecules for every glucose molecule– 2 from glycolysis– 2 from the Krebs cycle– 32-34 from the electron transport chain

The equation for the overall process of Cellular Respiration is:

C6H12O6 + 6O2 6CO2 + 6H2O + ATP

Glucose + Oxygen Carbon dioxide + Water + Energy

Relationship between Photosynthesis & Cellular Respiration:

• The reactants in photosynthesis are the same as the products of cellular respiration.

Cellular Respiration