Biology: DNA and RNA Structures

Base Pairing Rules

• Complementary Base Pairing:
  • Adenine (A) pairs with Thymine (T) in DNA and Uracil (U) in RNA.
  • Cytosine (C) pairs with Guanine (G) in both DNA and RNA.
• Hydrogen Bonds:
  • A-T pairs are connected by two hydrogen bonds.
  • C-G pairs are connected by three hydrogen bonds, making them stronger.

Nucleotide Composition

• Nucleotides:
  • Consist of three components: a phosphate group, a sugar molecule, and a nitrogenous base.
• Sugar Types:
  • DNA contains deoxyribose.
  • RNA contains ribose.
• Nitrogenous Bases:
  • DNA: Adenine, Thymine, Cytosine, Guanine.
  • RNA: Adenine, Uracil, Cytosine, Guanine.

RNA Vs DNA

• Structure:
  • DNA: Double-stranded helix.
  • RNA: Typically single-stranded.
• Function:
  • DNA: Stores and transmits genetic information.
  • RNA: Plays roles in protein synthesis and gene regulation.
• Stability:
  • DNA is more stable and less reactive due to the absence of a hydroxyl group on the 2' carbon.
  • RNA is more reactive and prone to degradation.

Structural Functions

• DNA:
  • Acts as the blueprint for genetic information, ensuring accurate replication and transmission during cell division.
• RNA:
  • Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes for protein synthesis.
  • Transfer RNA (tRNA): Transports amino acids to ribosomes during protein synthesis.
  • Ribosomal RNA (rRNA): Structural component of ribosomes, facilitating protein assembly.

Base Pairing Rules

• Adenine (A) pairs with Thymine (T) in DNA and with Uracil (U) in RNA.
• Cytosine (C) pairs with Guanine (G) in both DNA and RNA.
• A-T base pairs are linked by two hydrogen bonds, while C-G pairs are connected by three hydrogen bonds, giving C-G pairs greater stability.

Nucleotide Composition

• Nucleotides are made up of a phosphate group, a sugar molecule, and a nitrogenous base.
• The sugar in DNA is deoxyribose, while RNA contains ribose.
• Nitrogenous bases differ between DNA and RNA:
  • DNA includes Adenine, Thymine, Cytosine, and Guanine.
  • RNA includes Adenine, Uracil, Cytosine, and Guanine.

RNA Vs DNA

• DNA is structured as a double-stranded helix; RNA typically exists as a single strand.
• Primary function of DNA is to store and transmit genetic information; RNA is involved in protein synthesis and regulation of gene expression.
• DNA is more stable due to the lack of a hydroxyl group on the 2' carbon, making it less reactive compared to RNA, which is more prone to degradation.

Structural Functions

• DNA serves as the genetic blueprint, ensuring precise replication and transmission during cell division.
• Messenger RNA (mRNA) conveys genetic information from DNA to ribosomes for protein synthesis.
• Transfer RNA (tRNA) transports amino acids to ribosomes, facilitating the assembly of proteins.
• Ribosomal RNA (rRNA) is a key structural component of ribosomes, assisting in protein synthesis.