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Protein Synthesis. Step 2: Translation. Review. Protein Synthesis: The process by which the message of DNA is used to make proteins Step 1: Transcription Takes place in the nucleus Changes DNA to mRNA Base Pairs: A-U and C-G. Step Two: Translation “ to decode or decipher the meaning of”.
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Protein Synthesis Step 2: Translation
Review • Protein Synthesis: The process by which the message of DNA is used to make proteins • Step 1: Transcription • Takes place in the nucleus • Changes DNA to mRNA • Base Pairs: A-U and C-G
Step Two: Translation “to decode ordecipher the meaning of” • Now that our mRNA molecule has been made, it’s time for its message to be made into a protein sequence. • How does the mRNA sequence translate into an amino acid sequence?
G T C A phe ile val pro ala his asn asp cys arg leu met ser thr tyr gln lys glu trp gly Step Two: Translation • Problem: • There are 20 different amino acids. • There are 4 RNA bases.
Step 2: Translation • Translation in 3 steps: • mRNA leaves the nucleus and finds a ribosome in the cytoplasm • tRNA brings amino acids to the ribosome • rRNA joins the amino acids together by matching the codes between mRNA and tRNA
tRNA Ribosome (rRNA)
Step Two: Translation • Watch this simplified animation: http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf • Watch the more complex animation! • http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html
Step Two: Translation • So how do you exactly go about determining what protein your cells are going to make? • FIRST, divide the mRNA sequence into codons. • Codonsare three-base sections of mRNA: AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA
AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA ? Step Two: Translation • Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon:
? Step Two: Translation • Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon: AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA met
met Step Two: Translation • Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon: AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA
tRNA Ribosome (rRNA)
How does tRNA know where to go? tRNA has an anticodon that coordinates with the codon on mRNA Anti-codon and codon pair up! Anti-codon
RECAP: • DNA is transcribed into mRNA in the nucleus. • The mRNA leaves the nucleus and enters the cytoplasm. • The protein is translated from the mRNA sequence using tRNA and amino acids.