T RANSLATION Using RNA to make Protein
W HAT DOES IT MEAN TO T RANSLATE ? 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
K INDS 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
K INDS OF RNA mRNA
K INDS OF RNA tRNA Amino Acid Folded RNA Strand Anticodon (complementary to the mRNA codon)
K INDS OF RNA rRNA Ribosome Ribosomal RNA
T HE G ENETIC C ODE 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!
T HE G ENETIC C ODE 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 codon for methionine (Met) codon for leucine (Leu)
T HE G ENETIC C ODE How do you know which codons code for which amino acids? Use this!!!
T HE G ENETIC C ODE AUG is the start codon This is where translation will begin UAA, UAG, UGA are stop codons This is where translation will end
P RACTICE TRANSLATING CODONS : Codon=3 nucleotides that are read together If this is the strand of mRNA: UCGCACGGU The codons are:
P RACTICE TRANSLATING CODONS : Codon=3 nucleotides that are read together If this is the strand of mRNA: UCGCACGGU The codons are: UCG-CAC-GGU
P RACTICE 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?
P RACTICE 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
P RACTICE 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?
P RACTICE 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
T HE P ROCESS 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)