Mutation Bellwork Explain the role of m RNA

Mutation

Bellwork � Explain the role of m. RNA, t. RNA, and r. RNA in translation.

Objectives � Define mutation � Explain the difference between base substitution and frameshift mutation � Explain how mutations affect living things

Key Terminology � Mutation � Base substitution � Point mutation � Frameshift mutation

Definition � Any change in the nucleotide sequence of DNA � Can result from ◦ Single base change ◦ Large regions of the chromosome change

Mutations within a gene fall into two general categories �First category- ◦ Base substitution – replacement of one nucleotide with another ◦ aka point mutation Ex. Normal gene AUG AAG UUU GGC GCA Met Lys Phe Gly Ala Mutated Gene AUG AAG UUU AGC GCA Met Lys Phe Ser Ala

Second Category �Frameshift mutation ◦ adding or deleting a base can alter the reading frame (triplet groupings) ◦ the codons downstream from insertion/deletion will be regrouped into different codons Ex: Normal Gene AUG AAG UUU GGC GCA Met Lys Phe Gly Ala Base Deletion AUG AAG UUG GCG CAU Met Lys Leu Ala His

Think-Pair-Share Explain the difference between base substitution and frameshift mutation? PROPERTY OF PIMA COUNTY JTED, 2010 3

Mutagenesis �Process by which mutants are created �Can occur in two ways ◦ Spontaneous mutation �result from errors during DNA replication or recombination ◦ Exposure to a physical or chemical mutagen �Physical �exposure to x-rays and/or ultraviolet light �Chemicals that interfere with correct DNA replication �They insert themselves and distort the double helix causing errors

Effect of Mutations �No effect ◦ mutations can be neutral ◦ have little or no effect on protein structure or function �Harmful ◦ mutations that produce defective proteins that disrupt normal biological activity �Beneficial ◦ alter protein structure or function that enables to adapt better to their environment

Think-Pair-Share “Mutation is the driving force of evolution”. Explain that statement PROPERTY OF PIMA COUNTY JTED, 2010 3

20 Word Summary 21 48 37 13 14 18 23 In 20 words or less, summarize the most important aspects from today's lesson. PROPERTY OF PIMA COUNTY JTED, 2010 12