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Translation
protein synthesis, part 2
Translation
● Converts mRNA from transcription into
protein (polypeptide)
● Codon- a sequence of 3 RNA nucleotides
that code for an amino acid
○ there are 20 amino acids in our body
○ amino acid- monomer of protein
RNA Codon Chart
● Shows the amino acid
made from each codon
● one “start codon” (AUG)codes for methionine,
starts translation
● three “stop codons” signal
the end of a protein chain
RNA Codon Chart
RNA Codon Chart
Transfer RNA (tRNA)
● Contains an anticodon3 nucleotide RNA
segment that is
complementary to a
codon
● Contains an amino acid
Ribosome
● Made of rRNA and
proteins
● Consists of 2 subunits
○ small- holds on to
mRNA
○ large- holds on to
growing protein
Translation Process
● Translation starts at the
mRNA codon AUG
● tRNA with an anticodon of
UAC bonds with the codon in
a ribosome
● The amino acid methionine is
released from the tRNA
Translation Process
STEPS
● Exposed codon
attracts
complementary
tRNA
Translation Process
● Ribosome forms a
peptide bond
between the 2
amino acids and
breaks bond
between amino acid
and tRNA
Translation Process
● Ribosome pulls the
mRNA one codonlength
● The 1st tRNA
leaves the ribosome
Translation Process
● Another complementary tRNA pairs with
the next codon and repeats the same steps
● Process continues until a stop codon is
reached
● The protein is released and the ribosome
falls apart
Translation Analogy
● Restaurant
○ My burger order went to the kitchen on
a piece of paper
○ The DNA message goes to the
ribosome in the form of mRNA
Translation Analogy
● Restaurant
○ A cook reads the paper and gathers
ingredients to make a burger
○ A ribosome reads the mRNA and
assembles the amino acids to make a
protein