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Making Protein. How genes on a chromosome determine what proteins to make. The Language of Nucleotides. The sequence of the nucleotide bases are like a language The only letters in this language are A T C and G All words in this language are made up of three letters.
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Making Protein How genes on a chromosome determine what proteins to make
The Language of Nucleotides • The sequence of the nucleotide bases are like a language • The only letters in this language are A T C and G • All words in this language are made up of three letters
How many words can you spell if English had only 4 letters? D N E O
20 possible ‘words’ for ATCG • Every ‘word’ is an amino acid • Some words are like a period at the end of a sentence.
Transcription • The same as replication EXCEPT the sequence is copied to messenger RNA (mRNA) • A pairs with Uracil (U) instead of T • SINGLE strand. NOT double strand.
Transcribe the following sequence from DNA into mRNA • G-C-A-T-T-A-C-G-A • C-G-U-A-A-U-G-C-U
Practice • G-C-C-A-T-A • C-T-A-C-G-A • T-C-T-A-G-A • A-T-T-G-A-C
mRNA ‘words’ • Words are called codons • Every three letters is 1 codon • Codons are matched with anticodons to make proteins
Translation (reading the sequence) • Translation build proteins (the last of the central dogma DNA – RNA – Proteins)
Three types of RNA • Transfer RNA (tRNA) • Ribosomal RNA (rRNA) • Messenger RNA (mRNA)
Sequence of events • Amino acid attaches to tRNA • tRNA carries amino acid to rRNA • rRNA ‘sits’ on top of mRNA and reads the sequence • tRNA anticodons match with mRNA strand • Protein is formed by the matching • Translation stops when ‘stop codon’ appears
Practice • C-C-A-T-T-C DNA sequence