Question

Which of the following statements about the autotrophs is incorrect?

• A. They synthesize carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll.
• B. They store carbohydrates in the form of starch.
• C. They convert carbon dioxide and water into carbohydrates in the absence of sunlight.
• D. They constitute the first trophic level in food chains.

Answer 1

Answer: (C)

They convert carbon dioxide and water into carbohydrates in the absence of sunlight.

Hint - The producers (i.e., plants) generate their own food.

Part 1 - Autotrophic nutrition

• The primary producers present at the first trophic level in an ecosystem are autotrophic.
• These autotrophs perform photosynthesis wherein they use carbon dioxide and water in the presence of sunlight and chlorophyll to produce carbohydrates.

Chemical reaction: $C{O}_2\left(Carbondioxide\right)+H_{2}O\left(Water\right)\to C_6{H}_{12}{O}_6\left(Glucose\right)+O_2\left(Oxygen\right)$

• The photosynthesis process occurs inside the mesophyll cells present in the leaves.

Part 2 - Storage of carbohydrate

• The carbohydrate produced during this process is stored in the plant in the form of starch which can later be used to produce energy.

Part 3 - Conclusion

• Thus, from the above discussion, we can conclude that the (A), (B), and (D) statements are correct but the (C) statement mentioning the conversion of carbon dioxide and water into carbohydrates (i.e., Photosynthesis) occurs in the absence of sunlight is incorrect. Photosynthesis occurs in the presence of sunlight.

Final Step - The conversion of carbon dioxide and water into carbohydrates in the presence of sunlight.