Chemistry MCQs for NEET — Practice Questions with Answers

The base guanine (G) in DNA forms three hydrogen bonds with cytosine (C). This strong bonding is due to the three hydrogen bonds, making G-C pairs more stable compared to A-T pairs, which form only two hydrogen bonds.

Thymine (T) is a pyrimidine base that pairs with adenine (A) in DNA through two hydrogen bonds. Therefore, the base mentioned in the question is thymine (T).

Glucose does not give a violet color with Schiff's reagent. Schiff's reagent is typically used to test for aldehydes, and while glucose has an aldehyde group, it does not produce a violet color in this reaction.

Mutarotation of glucose in aqueous solution refers to the change in the optical rotation due to the interconversion between the alpha and beta anomers. The specific rotation of glucose in an aqueous solution is approximately $ + 52.5 ^ ext{circ} $.

Glucose is known as an aldohexose because it contains six carbon atoms and an aldehyde group. The term 'hexose' refers to the six carbon atoms, and 'aldo' indicates the presence of an aldehyde group.

Fructose is known as a ketohexose because it contains six carbon atoms and a ketone group. The term 'hexose' refers to the six carbon atoms, and 'keto' indicates the presence of a ketone group.

Starch is insoluble in water. It is a polysaccharide composed of glucose monomers and has a complex structure that does not dissolve easily in water.

In amylopectin, most of the glucose units are linked by α(1→4) glycosidic bonds. However, branching occurs at every 24 to 30 glucose units with α(1→6) glycosidic bonds. This means some α-D-glucose units are joined by C1-O-C6 linkage.