Question 21
Which of the following is a primary role of magnesium in plants?
A) Synthesis of proteins
B) Activation of enzymes
C) Formation of chlorophyll
D) Water absorption
Correct Answer: C) Formation of chlorophyll
Explanation: Magnesium is a central component of chlorophyll and is essential for photosynthesis.
Question 22
A plant exhibiting yellowing of older leaves is likely deficient in:
A) Nitrogen
B) Calcium
C) Iron
D) Potassium
Correct Answer: A) Nitrogen
Explanation: Nitrogen deficiency typically causes chlorosis, starting with the older leaves as nitrogen is mobile within the plant.
Question 23
What is the main function of iron in plants?
A) Energy storage
B) Chlorophyll synthesis
C) Cell wall formation
D) Water uptake
Correct Answer: B) Chlorophyll synthesis
Explanation: Iron is crucial for the synthesis of chlorophyll and is involved in various enzymatic reactions.
Question 24
Which of the following minerals is important for stomatal movement?
A) Nitrogen
B) Magnesium
C) Potassium
D) Calcium
Correct Answer: C) Potassium
Explanation: Potassium is essential for the opening and closing of stomata, thus regulating gas exchange and transpiration.
Question 25
What symptom is commonly associated with boron deficiency?
A) Leaf necrosis
B) Poor fruit development
C) Stunted growth
D) Chlorosis
Correct Answer: B) Poor fruit development
Explanation: Boron deficiency can lead to poor fruit and flower development, affecting overall yield.
Question 26
Which nutrient is involved in nitrogen fixation in legumes?
A) Potassium
B) Iron
C) Molybdenum
D) Phosphorus
Correct Answer: C) Molybdenum
Explanation: Molybdenum is essential for the enzyme nitrate reductase, which is involved in nitrogen fixation in legumes.
Question 27
Which of the following is NOT a function of potassium in plants?
A) Enzyme activation
B) Protein synthesis
C) Photosynthesis
D) Stomatal regulation
Correct Answer: B) Protein synthesis
Explanation: While potassium is important for many plant processes, protein synthesis primarily involves nitrogen and other elements.
Question 28
In plants, what is the function of sodium?
A) Promotes growth
B) Aids in photosynthesis
C) Regulates osmotic balance
D) Forms chlorophyll
Correct Answer: C) Regulates osmotic balance
Explanation: Sodium can play a role in regulating osmotic pressure in some plants, though it is not essential for all.
Question 29
Which of the following is a sign of magnesium deficiency?
A) Red leaves
B) Chlorosis between veins
C) Leaf curling
D) Blossom end rot
Correct Answer: B) Chlorosis between veins
Explanation: Magnesium deficiency leads to interveinal chlorosis, primarily in older leaves.
Question 30
What role does sulfur play in plants?
A) Formation of amino acids
B) Regulation of water loss
C) Synthesis of chlorophyll
D) Energy transfer
Correct Answer: A) Formation of amino acids
Explanation: Sulfur is a key component of amino acids and is essential for protein synthesis in plants.
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