Question

You have a large, healthy plant that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?a) While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.

b) Even though the plant received no visible light, it was able to use the short-wave part of the electromagnetic spectrum (gamma rays and X-rays) to carry out photosynthesis.
c) Even though it can't carry out the light reactions, the plant can still produce sugars because the Calvin cycle doesn't require light.
d) When light energy is not available, plants can derive energy from inorganic molecules.
e) None of the listed responses

Answer 1

Answer: A. While it did have access to light, the plant stored energy in the form of sugar or starch, and it was able to derive energy from the stored molecules during your vacation.

Step-by-step explanation:

Photosynthesis is the process by which carbon dioxide in the presence of sunlight and water, produce food in the form of glucose and give off oxygen which is necessary for the growth of plants.

Just as humans can survive a week or two without food but depending on stored energy, so also plants can also survive a short period without photosynthesis. It can achieve this by depending on stored molecules.

A large plant such as the one in the question obviously has some stored energy which can help it survive for some time.

Answer 2

a) While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.

Step-by-step explanation:

Plants and animals both store carbohydrates energy in the form of glycogen and starch respectively. So as animals can survive on energy reservoir for some days plants can also survive on stored energy in form of starch.

Plants turns the light energy to chemical energy by the process of photosynthesis. The thylakoid membrane of chloroplast synthesize the ATP and NADPH during light called as light reaction. While in dark reaction (calvin cycle) these ATP and NADPH are used to combine carbon atoms into sugar molecules. We know energy is stored in the process of combining carbon atoms.

So the energy can be stored in the form of starch in plants and can be utilized when needed. The mitochondria is the powerhouse of the cell where energy is produced.