Th2L01 Prokaryotic vs. eukaryotic genes

Eukaryotic genes
1. Exons
  1. Genome expressed sequence of DNA Genome expressed sequence of DNA
  2. Codes for a protein
  3. About 1.5% of DNA
  4. Found in mature mRNA
2. Introns
  1. Non-coding
  2. Interrupt mRNA
  3. 23% of DNA
  4. Not found in mRNA
3. Non-coding DNA
  1. Untranscribed regions near genes
    1. ca. 2% of non-coding regions of DNA
    2. Areas flanking genes, esp. at the 5' end are important regulatory elements that control the production of mRNA
  2. Repetitive DNA
    1. Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome
    2. The repeated units may be short and arranged tandemly (in series) or long and dispersed in the genome
    3. about 50% of DNA
    4. Main types
      1. Retrotransposable elements
        Characteristics
        moderately repetitive
        thought to move to randomly selected new locations
        method of movement unknown in human genome
        classified according to origin
        LINES
        Viral retrotransposable elements
        Long Interspersed Elements
        appears to contains its own reverse transcriptase
        SINES
        Non-viral retrotransposable elements
        Short Interspersed Elements
      2. Satellite DNA
        short sequences of DNA that are tandemly repeated as many as 10 million times in the DNA
        much of it is located in the telomeres
        8% of entire genome
        Role
        structural properties of DNA
        Clinical sig.
        Provides genetic fingerprint □ Used in paternity testing and forensic science
  3. Uncharacterised/junk DNA
    1. about 25% of DNA
Prokaryotic genes
1. Promoter - coding sequence (5' to 3')
2. Transcriptor terminator
3. Transcribed into mRNA
  1. mRNA translated by ribosomes to give a polypeptide

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Th2L01 Prokaryotic vs. eukaryotic genes

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	Created by Emma Allde about 8 years ago