Summary of Aerobic Respiration



Occurs in the cytoplasm.

First stage of both aerobic and anaerobic respiration.

Requires 2 ATP to begin, and starts with glucose.

Converts glucose to PGAL, then to pyruvate.

Converts 4ADP to 4ATP, and 2 NAD+ to 2 NADH.

For each glucose at the beginning, end products are 2 pyruvates, 2 ATP, and 2 NADH.


Between glycolysis and the Krebs cycle:

Pyruvates from glycolysis enter the inner compartment of the mitochondrion.

One carbon atom is removed, and 2 NADH are generated.

Remaining 2-carbon fragment is joined with coenzyme A to form acetyl-CoA.


Krebs cycle:

Occurs in the inner compartment of the mitochondrion.

Acetyl-CoA is joined to oxaloacetate.

Resulting 6-carbon molecule is sent through a series of reactions and broken down.

Energy from breakdown is used to convert ADP to ATP, NAD+ to NADH, and FAD+ to FADH2.

Carbon from breakdown is joined to oxygen to make carbon dioxide, which is a waste product.

Oxaloacetate is regenerated at the end of the cycle.

For each glucose that enters glycolysis, products of the Krebs cycle are 2 ATP, 6 NADH, and 2 FADH2.


Electron transport phosphorylation (ETP):

ETP begins in the inner compartment of the mitochondrion.

All the NADH and FADH2 constructed in previous steps are used.

Hydrogen ions and electrons are removed from NADH and FADH2.

Electrons are sent down electron transport system embedded in the inner membrane of the mitochondrion.

Electron transport system captures the energy of electrons to make ATP.

Hydrogen ions flow into the outer compartment of the mitochondrion, causing a concentration gradient.

Hydrogen ions then pass through ATP synthases, back into the inner compartment, in response to the concentration gradient.

Energy of the movement of the hydrogen ions is used by ATP synthases to make more ATP.

Oxygen is joined to the hydrogen ions to make water; this is why oxygen is necessary for aerobic respiration.

ETP results in the manufacture of 32 ATPs.


Total ATP production from aerobic respiration:  36 ATPs for each glucose that enters glycolysis (2 from glycolysis, 2 from Krebs cycle, 32 from ETP).