Why in the news?

  • Researchers at University College London successfully demonstrated that amino acids can spontaneously and selectively attach to RNA molecules.

RNA Molecule

  • What is it?: RNA (Ribonucleic Acid) is a nucleic acid that plays a central role in coding, decoding, regulation, and expression of genes.
  • Features:
    • It is usually single-stranded (unlike double-stranded DNA).
    • Composed of ribose sugar, phosphate backbone, and nitrogenous bases (Adenine, Uracil, Cytosine, Guanine).
  • Types of RNA:
    • mRNA (Messenger RNA):
      • Carries genetic information from DNA to ribosomes.
      • Acts as a template for protein synthesis.
    • tRNA (Transfer RNA):
      • Transfers specific amino acids to ribosomes.
      • Decodes mRNA codons into amino acids.
    • rRNA (Ribosomal RNA):
      • Structural and functional components of ribosomes.
      • Catalyzes peptide bond formation (acts as a ribozyme).
    • Other RNAs (Regulatory RNAs):
      • snRNA (small nuclear RNA): Involved in RNA splicing.
      • miRNA, siRNA: Regulate gene expression (RNA interference).
      • lncRNA (long non-coding RNA): Chromatin modification & transcriptional regulation.
  • Key Concepts regarding RNA:
    • Central Dogma of Molecular Biology: DNA → RNA → Protein.
    • Reverse Transcription: Some viruses (e.g., HIV, retroviruses) use RNA as genetic material, converting RNA → DNA via reverse transcriptase.
    • RNA World Hypothesis: Suggests early life on Earth may have relied solely on RNA for both genetic information storage and catalysis.
  • Significance of RNA:
    • Medical: Target for therapies (RNAi, mRNA vaccines).
    • Evolutionary Biology: Provides clues to life’s origin (RNA World).
    • Biotechnology: CRISPR, synthetic biology, genetic engineering.

Amino Acids

  • What are they?:
    • Amino acids are organic compounds containing an amino group (–NH₂), a carboxyl group (–COOH), a hydrogen atom, and a variable R-group (side chain) attached to a central carbon (α-carbon).
    • They are the building blocks of proteins, essential for growth, repair, metabolism, and signaling in living organisms.
  • Classification: Based on Nutritional Requirement;
    • Essential Amino Acids (9 in humans): Must be obtained from diet
    • Non-Essential Amino Acids: Synthesized in the body 
    • Conditionally Essential: Required in stress/illness
  • Functions of Amino Acids:
    • Structural: Form proteins (collagen, keratin).
    • Metabolic: Involved in enzymatic reactions, hormones (e.g., thyroxine from tyrosine).
    • Energy: Serve as energy source during fasting/starvation.
    • Signaling: Neurotransmitters (e.g., glutamate, GABA derived from glutamate).
    • Immune role: Glutamine, arginine critical for immunity.