Nutrition (Autotrophic and Heterotrophic) MCQs

Q1. Consider the following statements about nutrition: (I) Photosynthesis uses CO2 and water. (II) Chlorophyll traps light energy. (III) Saprophytes make their own food by photosynthesis. Which of the above statement(s) is/are correct?

• A.Only I and II
• B.Only III
• C.Only I
• D.None of these

Answer: A. Only I and II

What is the textbook's take? Correct: I, II. Does that line up with one of the options? Yes - Correct. And the rest? option B) 'Only III' is wrong because Re-check each statement individually; option C) 'Only I' is incorrect: Re-check each statement individually. Pick: A) Only I and II.

Q2. While testing a leaf for starch, a student first dips it in boiling water, then warms it in alcohol over a water bath until it turns colourless, before adding iodine; what is the purpose of the alcohol step here?

• A.To kill the leaf so it stops photosynthesising
• B.To add starch to the leaf for the test
• C.To dissolve out the green chlorophyll so the colour change is visible
• D.To make the iodine react faster with the leaf

Answer: C. To dissolve out the green chlorophyll so the colour change is visible

Boiling alcohol extracts chlorophyll, leaving the leaf pale. Against this pale background the blue-black colour produced by iodine on starch can be clearly seen.

Q3. A botanist grinds up spinach leaves and separates the cell contents; in which tiny green structures will she find the machinery that captures sunlight to build sugar?

• A.Mitochondria
• B.Ribosomes
• C.Vacuoles
• D.Chloroplasts

Answer: D. Chloroplasts

Chlorophyll is packed inside chloroplasts. These green organelles trap light energy and are the actual sites where carbon dioxide and water are combined into glucose.