Question

The particles in the nucleus of the cell, responsible for heredity, are called chromosomes which are made up of proteins and another type of biomolecules called nucleic acids. These are mainly of two types, DNA and RNA. Nucleic acids on hydrolysis yield a pentose sugar, phosphoric acid and nitrogen containing heterocyclic compound. Nucleic acids have a very diverse set of functions, such as cell creation, the storage and processing of genetic information, protein synthesis and the generation of energy cells. Although their functions may differ, the structure of DNA and RNA are very similar, with only a few fundamental differences in their molecular make-up. Based on the above information, answer the following questions: (a) Write two functions of DNA.

Hint:

DNA is the genetic material in most organisms. Nucleotides differ from nucleosides by the presence of a phosphate group. RNA contains ribose and uracil, while DNA has deoxyribose and thymine.

Answer 1

(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.
\[ \boxed{\text{DNA stores genetic information and regulates protein synthesis.}} \] (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: \[ \boxed{\text{Adenine} + \text{2-deoxyribose} + \text{Phosphoric acid}} \] (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: \[ \begin{tabular}{|c|c|} \hline Nucleoside & Nucleotide
\hline Base + Sugar & Base + Sugar + Phosphate
\hline No phosphoric acid group & Contains phosphoric acid group
\hline \end{tabular} \] \[ \boxed{ \begin{aligned} \text{Nucleoside} &= \text{Nitrogen base + Sugar}
\text{Nucleotide} &= \text{Nitrogen base + Sugar + Phosphate group} \end{aligned} } \] 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.
\[ \boxed{ \begin{aligned} \text{Similarity:} &\ \text{Both are made of nucleotides.}
\text{Difference:} &\ \text{DNA has thymine, RNA has uracil.} \end{aligned} } \]