Nucleic Acids and Genetic Material

Overview

• Nucleic acids are one of the four essential macromolecules in living systems.
• DNA (deoxyribonucleic acid) is crucial as it carries genetic information.
• Viruses can carry genetic information as RNA, but are not considered living organisms.

Structure of Nucleotides

• Nucleotides: Building blocks of nucleic acids with a shared base structure:
  • Pentose Sugar: Ribose or deoxyribose (pentagon shape)
  • Phosphate Group: Drawn as a circle (chemical formula: PO4 with a -3 charge)
  • Nitrogen Base: Simplified as a rectangle

DNA and RNA Structures

• DNA
  • Composed of many nucleotides bonded via sugar-phosphate bonds creating the backbone.
  • Four nitrogen bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C).
  • Double-stranded with bases linked by hydrogen bonds.
• RNA
  • Single-stranded with bases: Adenine (A), Guanine (G), Cytosine (C), Uracil (U).
  • Built through condensation reactions linking phosphate and sugar.

Differences Between DNA and RNA

1. Strands: DNA has two strands; RNA has one.
2. Nitrogen Bases: DNA uses Thymine; RNA uses Uracil instead.
3. Pentose Sugar: DNA has deoxyribose; RNA has ribose.

DNA Structure and Function

• Double Helix: DNA’s two strands are parallel and face opposite directions.
• Base Pairing Rules:
  • DNA: Adenine pairs with Thymine; Guanine pairs with Cytosine.
  • RNA: Adenine pairs with Uracil.
• Genetic Code: Stored in the sequence of nitrogen bases.

Importance of DNA

• DNA’s ability to store vast amounts of genetic information is due to its base pair diversity.
• Universal across organisms, suggesting a common evolutionary ancestor.
• Small and compact, efficiently storing information.

Evolutionary Significance

• DNA's uniformity across organisms supports the theory of a universal common ancestor.
• Its structure has facilitated the diversity of life on Earth.