Question

Choose the incorrect statement.

• A. The hormone glucocorticoid controls the level of excretion of water and salts by the kidney
• B. Vitamins A and K are fat soluble and are stored in the liver of human beings
• C. Denaturation of protein is due to loss of both the secondary and tertiary structures of the protein
• D. Complete hydrolysis of RNA gives nitrogen containing bases, a pentose sugar and phosphoric acid

Hint:

Glucocorticoids regulate metabolism, while mineralocorticoids (like aldosterone) regulate water and salt balance in the body.

Answer 1

The Correct Option is A

Step 1: Analyse statement (A).
Glucocorticoids are steroid hormones mainly involved in metabolism of carbohydrates, proteins and fats.
They do not regulate water and salt balance in the body.
The hormone responsible for regulating water and salt excretion is aldosterone (a mineralocorticoid).
Therefore, statement (A) is incorrect.

Step 2: Analyse statement (B).
Vitamins A and K are fat-soluble vitamins.
Fat-soluble vitamins are stored in the liver and fatty tissues of the body.
Hence, statement (B) is correct.

Step 3: Analyse statement (C).
Denaturation of proteins involves disruption of secondary and tertiary structures due to breaking of hydrogen bonds and other weak interactions.
However, the primary structure remains intact.
Thus, statement (C) is correct.

Step 4: Analyse statement (D).
RNA on complete hydrolysis yields nitrogenous bases, a pentose sugar (ribose), and phosphoric acid.
This is a standard property of nucleic acids.
Hence, statement (D) is correct.

Step 5: Final conclusion.
Only statement (A) is incorrect because glucocorticoids do not control water and salt excretion; this function is performed by mineralocorticoids.
Final Answer:
The incorrect statement is:
\[ \boxed{\text{(A) The hormone glucocorticoid controls the level of excretion of water and salts by the kidney}} \]