🔹 Anaerobic vs. Aerobic Respiration

• Aerobic respiration (with oxygen): 36 ATP
• Anaerobic respiration (no oxygen, like in yeast): Only 2 ATP

👉 So aerobic respiration is 18 times more efficient than anaerobic respiration.

🔹 Other Sources of Fuel (Not Just Glucose)

We eat more than just glucose. So our cells have ways to make ATP from fats and proteins too.

🍬 Sugars (like sucrose and starch):

These are broken down into glucose, which then enters glycolysis.

🥩 Proteins:

• First, proteins are broken into amino acids.
• These amino acids are deaminated (the amino group is removed).
• The remaining parts are turned into pyruvic acid, acetyl-CoA, or Krebs cycle molecules — all of which can be used to make ATP.

🧈 Fats (Lipids):

• Fats are broken into glycerol and fatty acids.
• Glycerol becomes glyceraldehyde 3-phosphate (a glycolysis intermediate).
• Fatty acids are broken into acetyl-CoA — which enters the Krebs cycle.

💡 Fats are excellent energy sources because they contain lots of hydrogen and carbon bonds, which release a lot of energy.