Video Transcript
Which of the following correctly links glucose, cellular respiration, and photosynthesis? (A) The glucose produced by cellular respiration can be broken down during photosynthesis to release energy. (B) The glucose produced by photosynthesis can be broken down during cellular respiration to release energy. (C) The glucose stored in the cells of a plant can be used as an energy source in cellular respiration and photosynthesis. Or (D) both cellular respiration and photosynthesis produce glucose that can be stored in the cells of a plant.
Let’s remove the multiple-choice options for now and remind ourselves about photosynthesis and cellular respiration in plants. You may recall that plants can synthesize their own food using light energy. They do this by carrying out photosynthesis. Photosynthesis is the chemical reaction in which light energy is used to convert carbon dioxide and water into glucose and oxygen. Although plants cannot move around, they still carry out a lot of complex processes, for example, the transport of sugars, which require energy. They get this energy through cellular respiration.
Cellular respiration is the chemical reaction in which glucose is broken down in the presence of oxygen to produce carbon dioxide and water and to release energy in the form of ATP. At this point, we can eliminate answer options (A) and (D) because we know that cellular respiration does not produce glucose.
You may have noticed that the products of photosynthesis are the reactants for cellular respiration. And vice versa, the products of cellular respiration are the reactants for photosynthesis. So some of the glucose produced by photosynthesis is used for cellular respiration in plants. Glucose can also be stored in plants as starch and lipids or used to synthesize cell walls and proteins.
We can now also eliminate answer option (C) because although stored glucose can be used as an energy source, it is only broken down in cellular respiration and not photosynthesis. We have therefore determined that the correct answer to the question is (B). The glucose produced by photosynthesis can be broken down during cellular respiration to release energy.
