A Summary of Energy Sources:

Carbohydrates: Excess carbohydrate intake is stored as glycogen in the liver and muscle for future use. Free glucose is used until it runs low, then glycogen reserves are tapped.

Fats: Excess fats are stored away in cells of adipose tissue. Fats are digested into glycerol (which enters glycolysis) and fatty acids (which enter the Krebs cycle). Because fatty acids have many more carbon and hydrogen atoms, they are degraded more slowly and yield greater amounts of ATP.

Proteins: Amino acids are released by digestion and travel in the blood. After the amino group is removed, the amino acid remnant is fed into the Krebs cycle.

This animation (Audio - Important) describes how the processes are linked.

Here are a few more animations on aerobic respiration. You should watch them, because they will make the process of aerobic respiration easier to understand. In most cases, they go into more detail than you need to learn. Use the review questions as a guide to the level of detail you need to know.

Krebs Cycle (Audio - Important)

Krebs Cycle in more detail (Audio - Important)

Electron Transport Phosphorylation (Audio - Important)

REVIEW: When molecules are broken apart in respiration
Answer the energy released in respiration is channeled into molecules of ATP.