Question

Which of the following is not a limiting factor A. CO2 concentration B.light intensity C.temperature D.water

Answer 1

Answer is D)Water

The three factors that affect the rate of photosynthesis are light intensity, carbon dioxide concentration, and temperature. We know this. We know how they affect the rate of photosynthesis. We know that they all have optimal levels of photosynthesis. But we didn’t know that if one of these factors were at a point lower than its optimal point of photosynthesis, it would then hinder the rate of photosynthesis and limit the organism. The factor that does this and is at the minimum point is therefore the limiting factor. Photosynthesis is determined by the rate of the current reaction taking the most time. That is the rate-limiting step, and all of the three limiting factors affect different rate-limiting steps.
light intensity: usually not the limiting factor because intensity is determined by the time of day (day/night), low intensities is when it could be the limiting factor, high intensities is when other factors are limiting
CO2 concentration: high concentrations are when other factors are limiting – because CO2 concentration in our atmosphere is low, CO2 is usually the limiting factor
temperature: low temperatures won’t let the enzymes work as fast as they can, intermediate temperatures are when other factors are limiting, high temperatures are pushing it – some enzymes denature