Protein Synthesis

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Protein Synthesis
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Prior Knowledge

• Protein Large complex molecule that is essential
  to all life
• Synthesis to build, put together
• Protein Synthesis building of proteins
• Proteins are made from amino acids
• Sequence of nucleotides code for specific
  proteins
• Enzymes are proteins which control the chemical
  reactions in a cell
• DNA contains the codes therefore controls the
  cells.
• Ribosome Place where proteins are assembled.

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RNA

• Ribonucleic Acid
• the workers
• Take instructions from the DNA and build the
  proteins one amino acid at a time.
• Single Stands
• Sugar is Ribose
• Bases Adenine, Uracil (pairs with Adenine),
  Guanine, Cytosine
• Three Types
• mRNA
• tRNA
• rRNA

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Types of RNA

• Messenger RNA (mRNA)
• Brings the DNAs instructions from the nucleus to
  the cytoplasm to the ribosome.
• Ribosomal RNA (rRNA)
• Binds to mRNA and uses the instructions to
  assemble amino acids.
• Transfer RNA (tRNA)
• Brings amino acids to the ribosome to be
  assembled.

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Transcription

• First step in the Protein Synthesis method
• DNA Helicase unzips the DNA
• Free RNA nucleotides pair with complimentary
  bases.
• A to U C to G
• One portion of DNA is copied.
• RNA nucleotides bond together and form ONE mRNA
  strand.
• Different in DNA replicationtwo new strands
  are formed in DNA replication.
• mRNA strands leaves the nucleus and heads to the
  ribosomes.
• DNA strands reconnect.

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Genetic Code

• mRNA contains a code using As, Us, Cs, Gs.
• Complete instructions for building a protein
• Code must be converted into protein language

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Genetic Code

• Codon group of THREE nitrogenous bases code for
  ONE amino acid.
• Ex UUU codes for Phenylalanine to be placed into
  a protein.
• Ex UAA is a stop codon
• Ex AUG is a start codon
• 64 combos are possible
• More than one codon can code for one amino acid
• UAU UAC are both Tyrosine codons
• One Codon only codes for 1 amino acid
• UAU only codes for Tyrosine
• UCU only codes for Serine

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Genetic Code

• ALL ORGANISMS USE
• SAME GENETIC CODE!!!

First Base in Codon C Second Base in Codon
A Third Base in Codon U
SoCAU codes for His (Histidine)
What does UAG code for?
Stop
What does AGC code for?
Serine
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• DNA Code T A C /A C G /A T A/G T G /A T T
• A U G U G C U A U C A C
  U A A

mRN Strand
Start
Cystine
Tyrosine
Histidine
Stop
Protein
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Translation

• Second Step in Protein Synthesis
• Occurs at the ribosomes
• Ribosome attaches to mRNA like a clothespin
• Sequence of bases is converted into sequence of
  amino acids
• Use Genetic Code
• Ex CAU to Histidine
• Ex UAG to Stop etc
• tRNA brings needed amino acids to the ribosome to
  build the protein.

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Translation

• tRNA has two sides
• amino acid side
• Nitrogenous base side
• Anticodon 3 bases of tRNA
• on opposite end of amino
• acid
• Pair up with mRNA bases
• What is the anticodon for the following mRNA
  strand?
• A U G

U A C
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Translation

• Amino acids bond with each other
• Forms polypeptide bonds or PROTEINS!!
• This Process continues until a STOP codon is
  reached

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