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Translation. Using RNA to make Protein. What does it mean to Translate?. Definition in English: to turn from one language into another; to change form
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Translation Using RNA to make Protein
What does it mean to Translate? • Definition in English: to turn from one language into another; to change form • Definition in science: to read the coded message of an RNA molecule and synthesize a new poly-peptide molecule (aka protein) at the ribosome in the cytoplasm • Definition in our own words: use RNA to make protein
Kinds of RNA • Before we talk about translation, you should know: • There are 3 types of RNA involved in the process of making protein • mRNA: messenger RNA carries the message of how to make a protein (this is the one we talked about yesterday!) • tRNA: transfer RNA transfers amino acids to the ribosome during translation • rRNA: ribosomal RNA is one small piece making up the ribosome
Kinds of RNA • mRNA
Kinds of RNA • tRNA Amino Acid Folded RNA Strand Anticodon (complementary to the mRNA codon)
Kinds of RNA • rRNA Ribosomal RNA Ribosome
The Genetic Code • The mRNA molecule carries the message of how to make the specific protein • That message is coded • Let’s learn how to crack that code!
codon for methionine (Met) codon for leucine (Leu) The Genetic Code • On the mRNA molecule, bases are read 3 at a time • A group of 3 bases in a row is called a codon • There are 64 possible different codons that code for the 20 different amino acids
The Genetic Code • How do you know which codons code for which amino acids? • Use this!!!
The Genetic Code • AUG is the start codon • This is where translation will begin • UAA, UAG, UGA are stop codons • This is where translation will end
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are:
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are: UCG-CAC-GGU
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are: UCG-CAC-GGU • How many codons are there?
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are: UCG-CAC-GGU • How many codons are there? 3
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are: UCG-CAC-GGU • How many codons are there? 3 • What amino acids are coded for?
Practice translating codons: • Codon=3 nucleotides that are read together • If this is the strand of mRNA: UCGCACGGU • The codons are: UCG-CAC-GGU • How many codons are there? 3 • What amino acids are coded for? Serine, Histadine, Glycine
The Process • mRNA molecule leaves nucleus and binds with ribosome • Beginning at the start codon, ribosome binds tRNA molecules with mRNA molecules according to correct codon—anticodon pairing • So for example, if the codon GAC is on the mRNA molecule, a tRNA molecule with the anticodon CUG will bind to it • The tRNA molecule brings its amino acid, which the ribsosome will bind to other amino acids being brought in to make a polypeptide chain (protein)