TranslationTranslation

Section 11-2 cont.Section 11-2 cont.

TranscriptionTranscription

TranslationTranslation

20 different amino acids20 different amino acids A group of three nucleotides in mRNA A group of three nucleotides in mRNA

code for one amino acid. This is called code for one amino acid. This is called a codon.a codon.

AUG – start codonAUG – start codon UAA – Stop codonUAA – Stop codon Converts mRNA to ProteinConverts mRNA to Protein Occurs at the ribosome in the Occurs at the ribosome in the

cytoplasmcytoplasm

1. When the strands of mRNA arrive 1. When the strands of mRNA arrive in the cytoplasm, ribosomes attach in the cytoplasm, ribosomes attach to them.to them.

2. Each tRNA molecule attaches to 2. Each tRNA molecule attaches to only one type of amino acid. The only one type of amino acid. The tRNA brings the amino acid to the tRNA brings the amino acid to the ribosome. ribosome.

3. On the opposite side of the tRNA 3. On the opposite side of the tRNA molecule from the amino acid site, molecule from the amino acid site, there is a sequence of 3 nucleotides there is a sequence of 3 nucleotides that are complement of the that are complement of the nucleotides in the codon.nucleotides in the codon.

44. First codon is AUG . First codon is AUG (the start codon). (the start codon). The ribosome then The ribosome then slides along the slides along the mRNA to the next mRNA to the next codon.codon.

5. A new tRNA 5. A new tRNA molecule carrying molecule carrying an amino acid an amino acid pairs with the pairs with the second mRNA second mRNA codon.codon.

6. The first and second amino acid 6. The first and second amino acid are jointed together by a peptide are jointed together by a peptide bond.bond.

7. The process continues, forming a 7. The process continues, forming a chain of amino acids until the chain of amino acids until the ribosome reach a stop codon.ribosome reach a stop codon.

TranslationTranslation