How Genes Work
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How Genes Work 14.1 Translation
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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. - PowerPoint PPT Presentation
Transcript of How Genes Work
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?
