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Genes, Mutations - Coggle Diagram

- - - - •Cytoskeleton proteins (actin)
        •cell respiration enzymes
        •polymerases
  - - - Operon
        
        In prokaryotes, a series of related genes follows one promoter, this region is called operon.
        
        Operon: Binding sites for repressor proteins
        
        Promoter: site for RNA polymerase binding
        
        Example:
        (Lac Operon)
      - Transcriptional control (efficient)
        DNA-X-RNA—>Protein—>Activated protein
        (Control factor between DNA and RNA)
        
        Translational control (faster)
        DNA—>RNA-X-Protein—>Activated protein
        
        Post-translational control (fastest)
        DNA—>RNA—>Protein-X-Activated protein
        
        Inducible vs repressible genes
        
        Inducible: if a gene is transcriptionally inactive until it receives a signal o start (off—>on)
        
        Repressible: if a gene is transcriptionally active until it receives a signal to stop (on—>off)
        
        Negative vs positive control
        
        Negative Control
        •Occures when a repressor protein binds DNA near or within a gene
        
        Prevents RNA polymerase from binding promoters
        
        Positive control
        •Ocurrs when an activator protein binds to DNA near or within a gene
        
        Helps RNA polymerase bind to promoters
- - - - Amino acids
        
        Ribosomes
        
        Proteins
        
        Structure
        
        One or more polypeptides that have a biological function
        
        Polypeptides: polymers of many amino acid monomers, joined by peptide bonds.
        
        All have the same amino structure (amino group, and carbonyl group), except for a unique R group
      - Translation occurs in a series of steps involving different factors.
        •Initiation
        •Elongation
        •Termination
        
        Initiation:
        •Initiates when the mRNA, leaves the nucleus and enters the ribosome, in the A site (binding site)
        •Then the ribosome starts translating with MET as the first amino acid.
        •tRNA’s start bringin NTP’s to the Aminoacytyl binding site.
        
        Elongation:
        •A tRNA with matching anti-codon enters the ribosome.
        •Peptide bond joins amino acids to grow peptide chain.
        •Translocation: ribosome moves 3 bases along mRNA (moves 5’—> 3’ along mRNA)
        •tRNA’s are released from E site.
        
        Termination:
        •Stop codon encountered, release factor binds.
        •Polypeptide is released from tRNA.
        •Ribosome subunits separate
    - - 3’ poly-A tail: Many A’s added. Length affects how long mRNA message survives in cytoplasm to be translated.
        5’cap: Modified G added. Allows attachment to ribosome.
      - RNA splicing
        
        •Introns: are sections cut out of the pre-mRNA.
        •Exons: remaining coding sections, spliced together.
        
        Alternative splicing
        
        Spliceosome
        
        The Spliceosome is composed by its own RNA’s that attach to the pre mRNA and choose the part of the exons that are going to be translated.
    - - Initiation: starts at promoters, where transcription factors bind to specific promoters to align RNA polymerase in front of the DNA to be transcribed.
        
        Promoter: specific DNA sequence where transcription starts.
        
        In eukaryotes a set of transcription factors called: basal transcription factors bind to the promoter
        
        In prokaryotes a type of transcription factor called sigma binds to the promoter
        
        Transcription factors: specialized proteins that bind to the promoter to align RNA polymerase with the DNA to be transcribed
        
        RNA polymerase: Enzyme that splits DNA, and transcribes, to create RNA.
      - Elongation:
        •RNA polymerase opens 10-20bp
        •Adds NTP’s to the 3” of the template
        •RNA polymerase peels away new RNA
        •DNA template “zips” back together behind the RNA polymerase.
      - Termination: transcription procedes until it reaches the terminator site, which causes the RNA polymerase to fall off the template strand
        
        Sequence made hairpin loop, pulling both RNA and polymerase away.