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How Genes Work. 14.1 Translation. What is translation?. Conversion of code to polypeptide Happens in cytoplasm Players tRNA Anticodon mRNA Ribosomes. What does the ribosome do?. Two parts to ribosome 60S, 40S subunits (eukaryotes) 50S, 30S subunits (prokaryotes) Polyribosomes.
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How Genes Work 14.1 Translation
What is translation? • Conversion of code to polypeptide • Happens in cytoplasm • Players • tRNA • Anticodon • mRNA • Ribosomes
What does the ribosome do? • Two parts to ribosome • 60S, 40S subunits (eukaryotes) • 50S, 30S subunits (prokaryotes) • Polyribosomes
What are the three steps of translation? • Initiation • Elongation • Termination
What happens in initiation? • Small subunit attaches at start codon • First tRNA arrives at P site • Large subunit attaches
What happens in elongation? • Second tRNA arrives at A site • P site tRNA transfers amino acids to A site • Ribosome shifts to open A site • “old” tRNA released at E site
What happens in termination? • Ribosome reaches stop codon • Release factor attaches • Subunits detach
How Genes Work 14.2 Mutations
What is a mutation? • Permanent change in DNA sequence • Can cause cancer • Carcinogenesis • Carcinogens vs. mutagens • Two types of mutations • Point • Frameshift
What is a point mutation? • Substitution of wrong nucleotide
What is a frameshift mutation? • Original: • THE BIG FLY HAD ONE RED EYE. • Point mutation: • THE BIT FLY HAD ONE RED EYE. • Frame shift mutation: • Addition: • THE BIT GFL YHA DON ERE DEY E. • Deletion: • THE BIF LYH ADO NER EDE YE. • Which is more dangerous?