Final answer:
The color that allows chloroplasts to produce sugar most efficiently is blue, due to the absorption spectrum of chlorophyll a and b, with blue and red light having the highest rates of absorption. The order of plant growth under different colored lights, considering their chlorophyll content and absorption, would be plant A (blue light) > plant C (orange light) > plant B (green light).
Step-by-step explanation:
The question pertains to chloroplasts and their pigment, chlorophyll, which are critical for photosynthesis. To understand which color light allows chloroplasts to produce sugar, it is important to discuss chlorophyll and light absorption. Plants contain chlorophyll a and b, which absorb light predominantly in the blue and red wavelengths, allowing photosynthesis to occur efficiently.
Chlorophyll absorbs violet-blue and red light and has a bluish-green color. Chlorophyll b, which is present along with chlorophyll a, shows a similar absorption spectrum but differs slightly in the specific wavelengths it absorbs. Given that plant A is under blue light, plant B is under green light, and plant C is under orange light, we would predict that the order of growth from most to least would be: plant A (blue light), plant C (orange light), and plant B (green light). This is because chlorophyll absorbs blue light most effectively, followed by red light (which is near the orange spectrum), whereas green light is least effective because it is mostly reflected by chlorophyll, not absorbed.
Chlorophyll is crucial for the production of sugars/carbohydrates during photosynthesis, where it uses the energy absorbed from light to convert carbon dioxide and water into glucose and oxygen. The other major product of photosynthesis, aside from sugars/carbohydrates, is oxygen.
The captured light energy is first utilized in the Light Dependent Reactions of photosynthesis, and then sugars are synthesized in a sequence of reactions known as the Calvin cycle, taking place within the chloroplast. The chloroplasts are the site where this entire process of photosynthesis transpires, converting light energy into chemical energy stored in glucose molecules, which serve as the primary energy source for cells.