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Protein
Synthesis
DNA
Transcription
Translation
Nucleus
Cytoplasm
Gene
mRN
tRNA
Amino Acid
Protein
Transcribing DNA
• Double stranded DNA unzips at Gene
• Gene – a coding section of DNA
• Helicase is the enzyme that does the unzipping
Helicase
T G G T A C A G C T A G T C A T CG T A C CG T
Matching bases of DNA & RNA
• U instead of T is matched to A
DNA
TACGCACATTTACGTACGCGG
mRNA
AUGCGUGUAAAUGCAUGCGCC
DNA vs. RNA
DNA
• deoxyribose sugar
• nitrogen bases
RNA
• ribose sugar
• nitrogen bases
• G, C, A, T
• T:A
• C:G
• G, C, A, U
• U:A
• C:G
• double stranded
• single stranded
Matching bases of DNA & RNA
• RNA nucleotides, floating in nucleus,
connect to DNA bases on one of the
exposed DNA strands
• Nucleotide – a phosphate, a sugar, a base
• RNA Polymerase is the enzyme that
attaches them together
A
G
C
U
A
G
G
U
U
C
A
AG
C
G
A
U
A
C
A C C
RNA
polymerase
A
U
G
T G G T A C A G C T A G T C A T CG T A C CG T
U
C
From nucleus to cytoplasm
nucleus
transcription
DNA
mRNA
cytoplasm
Translation - mRNA to Protein
• The Instructions  mRNA
• The Reader  Ribosome
• The Transporter of Amino Acids  Transfer RNA (tRNA)
ribosome
mRNA
A C C A U G U C G A U C A GU A GC A U G GC A
U GG
tRNA
aa
aa
aa
U A C
tRNA
aa
A GC
tRNA
aa
C
U AG
tRNA
aa
mRNA to protein = Translation
• tRNA drops off it’s Amino Acid
• tRNA then goes back into the cytoplasm, to pick up another
amino acid.
• All 20 Amino Acids are floating free and waiting in the Cytoplasm.
• The amino acid chain is left to become the functioning Protein.
cytoplasm
mRNA
amino acid chain
From mRNA to Protein
tRNA
translation
transcription
DNA
mRNA
nucleus
cytoplasm
mRNA codes for amino acids in triplet bases (codons)
DNA
TACGCACATTTACGTACGCGG
codon
mRNA
ribosome
AUGCGUGUAAAUGCAUGCGCC
?
protein
Met Arg Val Asn Ala Cys Ala
 Codon = block of 3 mRNA bases
amino acids (aa)
The mRNA Codon Chart
• For ALL life!
• Code has duplicates
• several codons for each
amino acid
• mutation insurance!
 Start codon


AUG
methionine
 Stop codons

UGA, UAA, UAG
DNA  Proteins  Cells  Bodies
 DNA has the information to build proteins

Genes - DNA coding sections
proteins
cells
DNA
DNA gets all the glory,
Proteins do all the work
bodies
How do proteins do all the work
• Proteins run and make living organisms
• Enzymes – protein catalysts
• control all chemical reactions in living organisms
• Structure
• all living organisms are built out of proteins
Only 4 DNA bases (A,U,G,C)
and 20 amino acids
Code for ALL life on Earth
TACGCACATTTACGTACGCGG
DNA
ribosome
mRNA
AUGCGUGUAAAUGCAUGCGCC
?
protein
aa
Met Arg Val Asn Ala Cys Ala
aa
aa
aa
aa
aa
aa
aa
for Protein Synthesis!
It’s Growth
It’s Repair
It’s YOU