Mutation

Explain the role of mRNA, tRNA, and rRNA in translation.

Define mutation Explain the difference between base

substitution and frameshift mutation Explain how mutations affect living things

Mutation Base substitution Point mutation Frameshift mutation

Any change in the nucleotide sequence of DNA

Can result from◦ Single base change◦ Large regions of the chromosome change

First category- ◦ Base substitution – replacement of one nucleotide

with another◦ aka point mutationEx. Normal gene

AUG AAG UUU GGC GCAMet Lys Phe Gly Ala

Mutated GeneAUG AAG UUU AGC GCAMet Lys Phe Ser Ala

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 GeneAUG AAG UUU GGC GCA

Met Lys Phe Gly Ala

Base Deletion AUG AAG UUG GCG CAU Met Lys Leu Ala His

Explain the difference between base substitution and frameshift mutation?

PROPERTY OF PIMA COUNTY JTED, 2010 3

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

Chemical Chemicals that interfere with correct DNA replication They insert themselves and distort the double helix causing

errors

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

“Mutation is the driving force of evolution”. Explain that statement


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In 20 words or less, summarize the most

important aspects from today's lesson.


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Mutation