NUCLEIC ACIDS DNA & RNA

• The genetic material exhibits four important characteristics: replication, storage of information, expression of information, and variation by mutation
• DNA Replication


  1. Initiation

  2. Primer Binding

  3. Elongation

  4. Proofreading and Correction

  5. Removal of RNA Primers

  6. Termination
• Replication


  The process by which DNA makes a copy of itself during cell division
• Storage of information


  Genes are the repository of all hereditary characteristics of organisms
• Expression of information


  Involves transcription of DNA to form mRNA, tRNA and rRNA, followed by translation to produce proteins
• Variation by mutation


  Genetic material generates variability through mutations, changes in chromosome number and rearrangements
• Transcription: RNA Synthesis


  1. Initiation

  2. Elongation

  3. Termination
• Translation of mRNA


  1. Activation of Amino Acids

  2. Initiation of Translation

  3. Elongation of the Peptide Chain

  4. Termination of Translation
• Types of RNA and Their Roles in Translation

  • mRNA (Messenger RNA)
  • tRNA (Transfer RNA)
  • rRNA (Ribosomal RNA)
• Codon


  A sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis
• The genetic code is the system by which genetic information (DNA or RNA sequences) is translated into proteins (amino acid sequences)
• Characteristics of the Genetic Code

  • Linear Form
  • Triplet Code
  • Unambiguous
  • Degenerate
  • Start and Stop Signals
  • Comma-less
  • Non-overlapping
  • Universal
• The genetic code is nearly universal across all organisms, from viruses to eukaryotes, with only minor exceptions
• The antisense strand/ Noncoding strand of the DNA is: 5' ATG GAT AAA GTT TTA AAC AGA GAG TGA 3'
• The sense strand/ coding strand is: 3' TAC CTA TTT CAA AAT TTG TCT CTC ACT 5'
• The mRNA derived from the sense strand is: 5' AUG GAU AAA GUU UUA AAC AGA GAG UGA 3'
• The polypeptide chain translated from the mRNA is: Met Asp Lys Val Leu Asn Arg Glu STOP