Powerpoint Dna Template - PowerPoint

							RNA

Ribonucleic Acid
Structure of RNA

    Single stranded
    Ribose Sugar
    5 carbon sugar
    Phosphate group
    Adenine, Uracil, Cytosine, Guanine
Types of RNA

  Three main types
  Messenger RNA (mRNA) – transfers
   DNA code to ribosomes for translation.
  Transfer RNA (tRNA) – brings amino
   acids to ribosomes for protein synthesis.
  Ribosomal RNA (rRNA) – Ribosomes are
   made of rRNA and protein.
Transcription

  RNA molecules are produced by copying part
   of the nucleotide sequence of DNA into
   complementary sequence in RNA, a process
   called transcription.
  During transcription, RNA polymerase binds to
   DNA and separates the DNA strands. RNA
   polymerase then uses one strand of DNA as a
   template from which nucleotides are
   assembled into a strand of mRNA.
mRNA
How Does it Work?

  RNA Polymerase looks for a region on
   the DNA known as a promoter, where it
   binds and begins transcription.
  RNA strands are then edited. Some
   parts are removed (introns) - which are
   not expressed – and other that are left
   are called exons or expressed genes.
The Genetic Code

  This is the language of mRNA.
  Based on the 4 bases of mRNA.
  “Words” are 3 RNA sequences called
   codons.
  The strand aaacguucgccc would be
   separated as aaa-cgu-ucg-ccc the amino
   acids would then be Lysine – Arginine –
   Serine - Proline
Genetic Codes
Translation
  During translation, the cell uses information
   from messenger RNA to produce proteins.
  A – Transcription occurs in nucleus.
  B – mRNA moves to the cytoplasm then to the
   ribosomes. tRNA “read” the mRNA and obtain
   the amino acid coded for.
  C – Ribosomes attach amino acids together
   forming a polypeptide chain.
  D – Polypeptide chain keeps growing until a
   stop codon is reached.
Translation to Protein
Translation
Mutations

  Gene mutations result from changes in a
   single gene. Chromosomal mutations
   involve changes whole chromosomes.
Gene Mutation

  Point Mutation – Affect one nucleotide
   thus occurring at a single point on the
   gene. Usually one nucleotide is
   substituted for another nucleotide.
  Frameshift Mutation – Inserting an extra
   nucleotide or deleting a nucleotide
   causes the entire code to “shift”.
Gene Mutation
Chromosomal Mutations

  Deletion – Part of a chromosome is deleted
  Duplication – part of a chromosome is
   duplicated
  Inversion – chromosome twists and inverts the
   code.
  Translocation – Genetic information is traded
   between nonhomologous chromosomes.
Chromosomal Mutations
Mutations
More Mutations
Gene Regulation

  In simple cells (prokaryotic) lac genes
   which are controlled by stimuli, turn
   genes on and off.
  In complex cells (eukaryotic) this process
   is not as simple. Promoter sequences
   regulate gene operation.
Review