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This concept explains how translation converts an mRNA message into a protein, starting with a start codon for methionine (Met) and coding for amino acids such as leucine (Leu). It discusses the importance of reading frames and correct codon reading, the common language of genetic code, and the role of tRNA and ribosomes in protein synthesis. The process involves binding of tRNA to start codon, formation of peptide bonds between amino acids, and release of the protein upon reaching a stop codon.
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KEY CONCEPT Translation converts an mRNA message into a protein.
Start codon for methionine (Met) codon for leucine (Leu) Translation converts mRNA messages into proteins. • A reading frame is a series of three non-overlapping nucleotides read, in order, by a cell • A codon is a sequence of three nucleotides that codes for an amino acid. • A codon must be read in the correct reading frame for the correct protein to be made. • The start codon is • AUG
A change in the order in which codons are read changes the resulting protein. • There is a “common language”: Regardless of the organism, the same codons code for the same amino acids.
The genetic code matches each RNA codon with its amino acid or function. • The genetic code matches each codon to its amino acid or function. • one start codon (AUG) codes for methionine • three stop codons(UAA, UAG, UGA) codons
Amino acids are linked together to become a protein. • An anticodon is a set of three nucleotides on a tRNA that bind to a complementary mRNA codon. • A tRNA (transfer RNA) carries amino acids from the cytoplasm to the ribosome
Ribosomes (yes, the organelles in the cytoplasm and the “rough stuff” on the rough E.R.) make proteins! • The large ribosomal subunit has 3 binding sites for tRNA. • The small ribosomal subunit binds to mRNA. 3. 6.
1. For translation to begin: • tRNA binds to a start codon and signals the ribosome to assemble. • A complementary tRNA anticodon binds to the exposed codon, bringing its amino acid close to the first amino acid.
2. The ribosome helps form peptide bonds between the amino acids. • 3. The ribosome pulls the mRNA strand the length of one codon AND…………………..
The now empty tRNA molecule drops off the ribosome. • A complementary tRNA anticodon binds to the next exposed codon. • Once the stop codon is reached, the ribosome releases the protein and disassembles. 4. tRNA 1. Amino acid 2. Peptide bond 8. anticodon 5. Reading frame 7. mRNA