Biomolecules

(a) Two important functions of DNA are: 1. Genetic Information Storage: DNA stores the hereditary material and transfers it from one generation to the next.
2. Regulation of Cellular Processes: DNA controls cell division, growth and protein synthesis by coding for enzymes and structural proteins.
(b) What products would be formed when a nucleotide from DNA containing Adenine is hydrolyzed?
Solution:
(b) A DNA nucleotide consists of three parts: - A nitrogenous base (in this case, Adenine) - A pentose sugar (2-deoxyribose) - A phosphate group On hydrolysis, it gives: (c)(i) What are nucleic acids? What is the difference between nucleotide and nucleoside?
Solution:
(c)(i) Nucleic acids are biological macromolecules made up of nucleotides joined by phosphodiester bonds. They carry genetic information and are of two main types: DNA and RNA.
Difference between nucleotide and nucleoside: OR (c)(ii) Give one similarity and one difference between DNA and RNA.
Solution:\ (c)(ii) Similarity: Both DNA and RNA are nucleic acids made up of nucleotides containing nitrogenous bases, a sugar, and a phosphate group.
Difference: - DNA contains deoxyribose sugar and the base thymine. - RNA contains ribose sugar and uracil instead of thymine.

(a) When glucose is heated with excess HI, it is fully reduced to form n-hexane. This proves that glucose has a straight-chain structure. (b) Br water
Solution:
(b) Br water is a mild oxidising agent. It oxidizes the aldehyde group (–CHO) in glucose to carboxylic acid (–COOH), forming gluconic acid.

Maltose is a disaccharide formed from two -D-glucose units. The glycosidic bond is formed between the C-1 of one glucose and C-4 of the other. Importantly: - One of the glucose units retains a free hemiacetal (anomeric) carbon. - This allows maltose to act as a reducing sugar. Thus: - Assertion is correct — maltose is indeed a reducing sugar. - Reason is also correct — the linkage involves C-1 to C-4. - Since the glycosidic linkage does not involve both anomeric carbons (unlike in sucrose), the free anomeric carbon enables reducing behavior.