Nucleic Acids: Key Biomolecules

Definition and Function

• Nucleic acids are biomolecules present in all living organisms.
• Responsible for:
  • Storage of genetic information.
  • Protein synthesis.

Structure of Nucleic Acids

• Composed of monomers called nucleotides.
• A nucleotide consists of:
  1. A 5-carbon sugar (e.g., ribose in RNA, deoxyribose in DNA).
  2. A phosphate group.
  3. A nitrogenous base.
• DNA nitrogenous bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).

Formation and Characteristics

• Nucleotides are linked by dehydration synthesis (polymerization), forming a sugar-phosphate backbone.
• Structure of DNA:
  • Composed of two strands forming a right-handed helix.
  • Strands are anti-parallel (oriented in opposite directions).
  • Held together by hydrogen bonds:
    • Guanine (G) pairs with Cytosine (C).
    • Adenine (A) pairs with Thymine (T).

RNA vs DNA

• RNA:
  • Contains sugar ribose.
  • Contains Uracil (U) instead of Thymine.
  • Typically single-stranded and less stable.
  • Functions in regulating expression of genetic information during protein synthesis.

Role of ATP

• ATP (Adenosine Triphosphate):
  • Modified nucleotide central to energy processing.
  • Composed of adenine base, ribose sugar, and three phosphate groups.
  • High-energy bonds between phosphate groups.
  • Functions as an energy carrier:
    • Energy is released when the terminal phosphate group is removed, forming ADP (Adenosine Diphosphate).
    • ADP can be recharged to ATP by cellular energy pathways.