Post on 17-Jan-2016
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DNADNA mRNA RNA ProteinProtein
Nuclearmembrane
TranscriptionTranscription
TranslationTranslation
DNA
mRNA
Ribosome
Protein
EukaryotEukaryotic Cellic Cell
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What is the name of What is the name of this pathway to this pathway to
making a protein?making a protein?DNADNA
mRNAmRNA
ProteinProtein
1. mRNA is transcribed from DNA
2. mRNA is translated into a protein
Transcription
Translation
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RNA RNA VocabulaVocabula
ryry
codon
Each group of three nitrogenous bases located on mRNA.
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ribosomal RNA (rRNA)
The two-part ribosome that reads mRNA
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amino acidCreate proteins when arranged in a chain.
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transfer RNA (tRNA)
Carries amino acids from the cytoplasm to the ribosome
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UA C
methionine
anticodonEach group of nitrogenous bases that complements a codon.
These groups of bases are located on tRNA.
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Making a Making a ProteinProtein
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Protein SynthesisProtein Synthesis The production (creation) of The production (creation) of
proteinsproteins Two phases:Two phases:
Transcription Transcription & & TranslationTranslation mRNA must be mRNA must be made before it made before it
leaves the nucleusleaves the nucleus of eukaryotic of eukaryotic cellscells
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TranslationTranslation• Three steps:Three steps:
1.1. initiationinitiation: start codon (AUG): start codon (AUG)
2.2. elongationelongation: amino acids : amino acids linkedlinked
3.3. terminationtermination: stop codon : stop codon (UAG, UAA, or UGA).(UAG, UAA, or UGA).
Let’s Make a Protein !Let’s Make a Protein !
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mRNA Codons Join the mRNA Codons Join the RibosomeRibosome
PSite
ASite
Largesubunit
Small subunit
mRNAmRNA
A U G C U A C U U C G
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InitiationInitiation
mRNAmRNA
A U G C U A C U U C G
2-tRNA
G
aa2
A U
A
1-tRNA
U A C
aa1
anticodon
hydrogenbonds codon
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mRNAmRNA
A U G C U A C U U C G
1-tRNA 2-tRNA
U A C G
aa1 aa2
A UA
anticodon
hydrogenbonds codon
peptide bond
3-tRNA
G A A
aa3
ElongationElongation
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mRNAmRNA
A U G C U A C U U C G
1-tRNA
2-tRNA
U A C
G
aa1
aa2
A UA
peptide bond
3-tRNA
G A A
aa3
Ribosomes move over one codon
(leaves)
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mRNAmRNA
A U G C U A C U U C G
2-tRNA
G
aa1
aa2
A UA
peptide bonds
3-tRNA
G A A
aa3
4-tRNA
G C U
aa4
A C U
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mRNAmRNA
A U G C U A C U U C G
2-tRNA
G
aa1aa2
A U
A
peptide bonds
3-tRNA
G A A
aa3
4-tRNA
G C U
aa4
A C U
(leaves)
Ribosomes move over one codon
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mRNAmRNA
G C U A C U U C G
aa1aa2
A
peptide bonds
3-tRNA
G A A
aa3
4-tRNA
G C U
aa4
A C U
U G A
5-tRNA
aa5
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mRNAmRNA
G C U A C U U C G
aa1aa2
A
peptide bonds
3-tRNA
G A A
aa3
4-tRNA
G C U
aa4
A C U
U G A
5-tRNA
aa5
Ribosomes move over one codon
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mRNAmRNA
A C A U G U
aa1
aa2
U
primaryprimarystructurestructureof a proteinof a protein
aa3
200-tRNA
aa4
U A G
aa5
C U
aa200
aa199
terminatorterminator or stopor stop codoncodon
TerminationTermination
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End Product –The End Product –The Protein!Protein!
• The end products of protein The end products of protein synthesis is a synthesis is a primary structureprimary structure of a proteinof a protein
• A A sequence of amino acidsequence of amino acid bonded together by peptide bonded together by peptide bondsbonds
aa1
aa2 aa3 aa4aa5
aa200
aa199
Kno-Gen Review
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1) Transcription
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2) Translation2) Translation
methionine glycine serine isoleucine glycine alanine stopcodon
proteinprotein
A U G G G C U C C A U C G G C G C A U A AmRNAmRNA
startcodon
Example structure of a proteinExample structure of a protein
aa aa aa aa aa aa
peptide bonds
codon 2 codon 3 codon 4 codon 5 codon 6 codon 7codon 1
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A codon chart does not need to A codon chart does not need to be memorized.be memorized.