Download DNA PROTEIN

DNA  PROTEIN
The Story of Protein Synthesis
DNA  PROTEIN
• http://www.youtube.com/watch?v=983lhh2
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DNA  PROTEIN
• DNA contains instructions for copying itself
• DNA also contains instructions for
– Making mRNA (Messenger RNA)
– Making proteins (but ribsomes do the work)
• DNA = double strand, RNA = single strand
DNA  PROTEIN
• DNA’s genetic message = specific order of
nucleotides on the DNA chain
– They’re not just stuck randomly stuck on!
• Nucleotide order (or sequence) is a coded
language
– Code determines an organism’s traits
DNA  PROTEIN
• TRANSCRIPTION MAKES mRNA
– Transcription = making a copy
• TRANSLATION MAKES PROTEINS
– Translation = reading the copy & putting it in a
different “language”
– RIBOSOMES DO THIS
• DNA  mRNA  PROTEIN
DNA  PROTEIN
Transcription
• DNA is unzipped
• mRNA strand is made (synthesized) kind
of like DNA is made during replication
• mRNA uses Uracil (U) instead of
Thymine (T)
– In transcription (A+U) and (C+G)
DNA  PROTEIN
Transcription
• WHY CAN’T PROTEINS JUST BE
TRANSLATED RIGHT FROM DNA?
– Using RNA provides protection for DNA & its
info
– Using RNA allows more protein copies to be
made at the same time
– BLUEPRINT EXAMPLE
DNA  PROTEIN
Transcription
• http://www.youtube.com/watch?v=OtYz_3r
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DNA  PROTEIN
Translation
• In translation, RIBOSOMES read the
“code” and make chains of amino acids
based on what the code is telling them.
– Chains of amino acids = proteins
DNA  PROTEIN
Translation
CRACKING THE CODE
• mRNA code is a triplet code
– 3 N-bases read together = codon
– Codons tell which amino acid to make
• AUG = start (or Met)
• UAA, UAG, UGA = stop
DNA  PROTEIN
Translation
• http://www.youtube.com/watch?v=HQYH7
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DNA  PROTEIN
Translation
• DNA says
– ACCAAACCG
• RNA replies
– UGGUUUGGC
• Ribosomes make
– Trp-Phe-Gly