Structure and Function of RNA

Introduction

• RNA as a Polymer
  • RNA is a polymer, categorized under biological molecules.
  • The monomer of RNA is a nucleotide.
  • Nucleotide components:
    • Ribose Sugar: A pentose sugar with five carbons.
    • Nitrogenous Bases: Adenine, Guanine, Cytosine, Uracil.
    • Phosphate Group: Single phosphate group.
  • Structural similarity to DNA:
    • RNA contains ribose instead of deoxyribose.
    • Uracil in RNA replaces Thymine in DNA.

Function of RNA

• Primary Role: Copy and transfer genetic information.
• Types of RNA:
  1. mRNA (Messenger RNA)
     • Copies one gene from DNA.
     • Shorter than DNA, allowing it to exit the nucleus.
     • Single-stranded; three bases (codons) code for one amino acid.
     • Degraded after protein synthesis due to exposure to enzymes.
  2. tRNA (Transfer RNA)
     • Found only in the cytoplasm.
     • Single-stranded, folds into a cloverleaf shape maintained by hydrogen bonds.
     • Transfers specific amino acids to mRNA on the ribosome.
     • Contains anticodons for complementary base pairing with mRNA codons.
  3. rRNA (Ribosomal RNA)
     • Combines with proteins to form ribosomes.

Differences Between RNA and DNA

• Monomer Differences:
  • DNA vs RNA Nitrogenous Bases: Thymine (DNA) vs Uracil (RNA).
  • Sugar Type: Deoxyribose (DNA) vs Ribose (RNA).
• Polymer Differences:
  • DNA is longer, containing the entire genome (~23,000 genes).
  • RNA (mRNA) is much shorter, representing a copy of only one gene.
  • DNA is double-stranded, whereas RNA is single-stranded.

Conclusion

• Understanding RNA's structure and function is crucial for genetic information processing.
• Differences in RNA and DNA highlight their specific roles in cellular biology.

• Reminder: Carefully read exam questions about RNA and DNA to distinguish between structural and functional differences.