Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
Two cells each break down glucose molecules. The first has plenty of oxygen. The second has none. (a) How many ATP does each cell make? (b) How many glucose molecules would the second cell need to make as many ATP as the first?
Respiration releases the energy of glucose. Glucose is split into pyruvate in the cytoplasm. Without oxygen, yeast makes ethanol and carbon dioxide, and muscles make lactic acid: about 2 ATP for each glucose. With oxygen, in the mitochondria, pyruvate becomes carbon dioxide and water: about 38 ATP for each glucose.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. With oxygen. ATP.
Step 2. Without oxygen. ATP.
Step 3. Glucose for the same energy. The second cell gets ATP from each molecule, so it needs glucose molecules.
Answer: (a) ATP and ATP. (b) glucose molecules, times as many.
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