1. How Genes Work 14.1 Translation

2. What is translation?  Conversion of code to polypeptide  Happens in cytoplasm  Players  tRNA  Anticodon  mRNA  Ribosomes

3. What does the ribosome do?  Two parts to ribosome  60S, 40S subunits (eukaryotes)  50S, 30S subunits (prokaryotes)  Polyribosomes

4. What are the three steps of translation?  Initiation  Elongation  Termination

5. What happens in initiation?  Small subunit attaches at start codon  First tRNA arrives at P site  Large subunit attaches

6. 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

7. What happens in termination?  Ribosome reaches stop codon  Release factor attaches  Subunits detach

8. How Genes Work 14.2 Mutations

9. What is a mutation?  Permanent change in DNA sequence  Can cause cancer  Carcinogenesis  Carcinogens vs. mutagens  Two types of mutations  Point  Frameshift

10. What is a point mutation?  Substitution of wrong nucleotide

11. 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?