Biomolecules

When two alpha-glucopyranoses are condensed together, the alcohol group of the first carbon of one alpha-glucopyranoses condenses with the alcohol group of the fourth carbon of the next alpha-glucopyranose. With one molecule of water removed, the two alpha-glucopyranoses are linked together. The chemical bond is called, more precisely, the alpha-1, 4-glycosidic bond.

1, 2-glycosidic linkage is found in sucrose, a disaccharide, where one glucose molecule and one fructose molecule are linked together by this bond.

Glucose on reacting with Benedict’s solution does not give violet precipitate. Benedict reagent is used to detect the presence of sugar (reducing sugar) in sample. When it is used to test monosaccharides such as glucose, the solution progress in the colours of orange, yellow, green, red and then brick red or brown precipitate within 7-10 minutes. A colour change would signify the presence of reducing sugar.

Ninhydrin is a powerful oxidizing agent widely used in biochemistry and forensic science for detecting amino acids in proteins. When ninhydrin reacts with amino acids, it produces a deep purple color known as Ruhemann's purple. This color change occurs because ninhydrin reacts with the free amino groups in amino acids to form a complex that absorbs light in the visible spectrum, specifically around 570 nm.

Here’s a simplified chemical reaction illustrating the formation of Ruhemann's purple :

$ \mathrm{RCH(NH_2)COOH} + 2 \;\mathrm{ninhydrin} \rightarrow \mathrm{\text{Ruhemann's purple}} + \mathrm{CO_2} + \mathrm{NH_3} + \mathrm{H_2O} $

Where :

$\mathrm{RCH(NH_2)COOH}$ represents the amino acid

The products include Ruhemann’s purple, carbon dioxide ($ \mathrm{CO_2} $), ammonia ($ \mathrm{NH_3} $), and water ($ \mathrm{H_2O} $).

Therefore, the correct option is :

$ \boxed{\text{Option A : Ninhydrin}} $

Adenylic acid, cytidilic acid and guanylic acid are nucleotides. Any nucleotide is composed of three components – nitrogen base (adenosine cytosine, guanine), ribose sugar and a phosphate group. These are monomer unit of nucleic acid cRNA and DNA.

Adenine, cytidine, thymidine are nucleosides. Uracil, cytosine and adenosine are nitrogenous bases.

Ribonuclease, chitinase and cellulose enzyme are used in many important biotechnological methods and procedures.

Carbohydrates, fats and proteins, all can be used as a substrate in cellular respiration. All of them get converted to acetyl Co-A when they enter Krebs’ cycle during aerobic cellular respiration.