Translation PROTEIN SYNTHESIS

4 Components used in Translation 1.mRNA- the message to be translated into protein. 2.Amino acids- the building blocks that are linked together to form the protein. 3.Ribosomes- the “machines” that carry out translation.

4.tRNA (transfer RNA)- brings an amino acid to the mRNA and ribosome. One end of a tRNA molecule has an anticodon that complements with an mRNA codon. The other end has a specific amino acid. A tRNA molecule with a particular anticodon always carries the same type of amino acid.

How does translation occur? 1.The ribosome binds to the mRNA molecule. 2.The tRNA with the anticodon that complements the first codon on the mRNA binds to the first site on the ribosome. 3.Another tRNA with the anticodon that complements the second codon on the mRNA binds to the second site on the ribosome.

4.A peptide bond forms between the first two amino acids. 5.The first tRNA leaves, and the ribosome moves along the mRNA to the next codon. 6.The next tRNA brings in the next amino acid, and a peptide bond is formed between this amino acid and the growing amino acid chain. 7.The process continues with the ribosome moving along the mRNA molecule and the amino acids linking together until a STOP codon is reached.

Transcription and translation URLs

The CODE of translation

mRNA nucleotides are translated in groups of 3 called codons. AUGCACUGCAGUCGAUGA CODONS

Each codon codes for a specific amino acid. 20 different amino acids can be used in different combinations to form a protein. For example: mRNA codonamino acid AAUasparagine CGCarginine GGGglycine

Amino Acid sequence determines the 3-D protein shape Interactions between amino acids cause folding and bending of the chain Examples: –positive (+) and negative (-) parts of amino acids are attracted to each other. –hydrophobic regions are attracted to each other Folding Structure levels structure.swf

How is the amino acid sequence determined? The mRNA Each codon is a code for one amino acid DNA sequence: T A C C G A G A T T C A mRNA sequence: A U G G C U C U A A G U amino acid sequence: Met -- Ala -- Leu -- Ser

UCAG U UUU Phenylalanine (Phe) UCU Serine (Ser)UAU Tyrosine (Tyr)UGU Cysteine (Cys)U UUC PheUCC SerUAC TyrUGC CysC UUA Leucine (Leu)UCA SerUAA STOPUGA STOPA UUG LeuUCG SerUAG STOP UGG Tryptophan (Trp) G C CUU Leucine (Leu)CCU Proline (Pro)CAU Histidine (His)CGU Arginine (Arg)U CUC LeuCCC ProCAC HisCGC ArgC CUA LeuCCA Pro CAA Glutamine (Gln) CGA ArgA CUG LeuCCG ProCAG GlnCGG ArgG A AUU Isoleucine (Ile) ACU Threonine (Thr) AAU Asparagine (Asn) AGU Serine (Ser)U AUC IleACC ThrAAC AsnAGC SerC AUA IleACA ThrAAA Lysine (Lys)AGA Arginine (Arg)A AUG Methionine (Met) or START ACG ThrAAG LysAGG ArgG G GUU Valine ValGCU Alanine (Ala) GAU Aspartic acid (Asp) GGU Glycine (Gly)U GUC (Val)GCC AlaGAC AspGGC GlyC GUA ValGCA Ala GAA Glutamic acid (Glu) GGA GlyA GUG ValGCG AlaGAG GluGGG GlyG

Your turn to practice DNA Bingo Translation exercise (Find the secret message) Genes to proteins-practice worksheet. –or Complete the “Translation Practice” worksheet