DNA Structure: Nucleotides as Monomers of Nucleic Acids
Introduction to DNA
Deoxyribonucleic acid (DNA) is the hereditary material in almost all living organisms. It carries the genetic instructions for the development, functioning, growth, and reproduction of all known organisms.
Key Concept: DNA is a polymer made up of repeating units called nucleotides, which are the monomers of nucleic acids.
Learning Objectives
- ✓ Identify the three components of a nucleotide
- ✓ Understand the primary structure of DNA
- ✓ Describe the double helix model
- ✓ Apply the principle of complementarity
1. Nucleotide Structure: The Building Blocks
Each nucleotide consists of three components working together:
1. Phosphate Group (PO₄³⁻)
Contains phosphorus and oxygen atoms. It acts as the "connector," linking to the sugar of the next nucleotide, and provides the acidic nature of DNA.
2. Deoxyribose Sugar
A 5-carbon (pentose) sugar ring. The term "deoxy" indicates that it lacks one oxygen atom at the 2' position compared to ribose found in RNA.
3. Nitrogenous Base
The information carrier. Depending on the nucleotide, this is Adenine (A), Thymine (T), Guanine (G), or Cytosine (C).
Interactive visualization — available in the full lesson
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