Answer: Fehling's solution.
- A Fehling's solution
- B Iodine solution
- C Ninhydrin
- D Biuret reagent
Correct answer: A. Fehling's solution
Explanation: Reducing sugars (those with free aldehyde or keto groups) reduce Fehling's solution to Cu<sub>2</sub>O (brick-red).
Two amino acids join via a condensation reaction: the carboxyl -OH of one and an amine -H of the other are eliminated as water, leaving a peptide bond (-CO-NH-) linking them into a dipeptide; repeating this builds a full protein chain.
Concept context
The chemistry of life: carbohydrates, proteins, lipids, nucleic acids, enzymes, and vitamins. Understand their structures, classification, and biological functions. Highly relevant for NEET and Class 12 board exams.