Dna and protein synthesis

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Dna and protein synthesis
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Proteins where do they come from?

• Genetic transcription, translation and regulation.

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Proteins

• You learned about these back in September
  remember chemistry? (Ugh!!!!!)
• Macromolecules
• Made of amino acids
• Peptide bonds join 50 3000 amino acids

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We get proteins from

• Plants make proteins by using materials made in
  photosynthesis
• Animals eat those proteins to get the amino acids
  they need to make their own proteins. Or we eat
  animals that ate the plants (Whopper, please!)

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Amino acids
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These are amino acids with two different R-Groups
R
R
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Production of a polypeptide chain

• Amino acid 1 is added to amino acid 2 by forming
  a peptide bond between them.
• This continues at the ribosome until all the
  amino acids of a polypeptide are placed in the
  right order.

Aa-2
Aa-1
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Remember the pathway for making proteins in the
cell?
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Two major steps of protein synthesis
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RNA and DNA Nucleotides
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Transcription - Dna codes for RNA
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transcription
translation
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Central dogma
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If the Dna code is this TACGAGtTACATAAA

• what is the RNA code?

AUGCUCAAUGUAUUU
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DNA codes for RNA codons,RNA codes for the
protein
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Translation occurs at the ribosome when the tRNA
brings the amino acid in the proper order as
determined by the mRNA
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Mrna codons for the amino acids
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Removal of the introns (not needed) and splicing
of the exons (expressed) part of the code
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A tRNA molecule showing its anticodon which
complements mRNAs codon and the amino acid
attached to its opposite end
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Polysomes many ribosomes moving along and
reading the same mRNA molecule they all make
the same protein
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Ribosome structure with mRNA passing through and
causing the creation of an amino acid chain
(protein)
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The tRNA with the growing polypeptide chain is at
the P site, while the next amino acid is brought
to the A site by another tRNA.
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Initiation
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elongation
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termination

• Occurs when the stop codon is reached.
• The polypeptide chain is complete
• The mRNA is either read by another ribosome or it
  is recycled so its nucleotides can be used again.
• The ribosome large and small subunit falls apart
  from each other

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Transcription DNA codes for RNA
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RNA processing
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Translation Initiation
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Translation - Elongation
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Translation - Termination
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Entire Translation Procedure
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Now the protein passes from the ribosome and
moves into the rough endoplasmic reticulum.Do
you remember what happens to it next?
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You should now understand this diagram. If you
dont, then you need to come in after school and
go through this presentation on you own at your
own speed.