protein synthesis

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Created by
Katie

Cards (7)

  • transcription
    process of copying sections of DNA base sequence to produce smaller molecules of mRNA, which can be transported out of the nucleus via the nuclear pores to the ribosomes.
  • transcription
    1. section of DNA unwinds+ unzips by a helicase breaking hydrogen bonds between bases.- sense strand= contains code for protein- antisense strand= complementary copy of sense strand, acts as template so RNA strand carries same base pair sequence as sense
    2. free RNA nucleotides base pair with anti-sense strand.
    3. RNA polymerase forms phosphodiester bonds between nucleotides.
    4. transcription stops- mRNA detaches from template and travels out nucleus through nuclear pores to ribosomes.
  • ribosomal DNA
    =maintains structural stability of the protein synthesis sequence and plays a biochemical role in catalysing the reaction
  • transfer tRNA
    = strand of RNA folded in a way that 3 bases (anticodon) which will bind to a complementary codon on mRNA
  • translocation
    = mRNA binds to a specific site on the small subunit of a ribosome which holds it in position while it's decoded into a sequence of amino acids.
  • translocation
    1. mRNA associates to small subunit of ribosome (start codon)
    2. tRNA with complementary anticodon binds to mRNA codon, this tRNA carries the amino acid.
    3. another tRNA with anti-codon+ amino acid binds to next codon on mRNA.
    4. 1st amino acid is transfered to amino acid on 2nd tRNA by formation of a peptide bond catalysed by peptidyl transferase.
    5. ribosome moves along mRNA, releasing 1st tRNA, process repeats until ribosomes reaches end of mRNA.
  • ATP 

    = adenosine triphosphate, made from an adenine base+ ribose sugar+ 3 phosphate groups.
    • cells need energy for: synthesis of large molecules, transport of substances across membranes, movement.
    • hydrolysis reaction= ATP+H2O= ADP+Pi+ energy (ADP= adenosine diphosphate)
    • properties for energy release: 1 step reaction to release energy, reaction is reversible, water soluble, small, easily regenerated