Bell Ringer – 4/22/2014 Happy Earth Day!

Bell ringers are next to the homework bin. You have 5 mins after the bell rings to complete it.

Today Alien Activity wrap-up Lecture/notes – Mutations (13.3) Independent work – Study Guide

Data Tables for Alien Gene Analysis

GENE ADNA CAA GGA TATmRNA GUU CCU AUAAmino Acids Val - Pro - IleTrait Hairless

Mutation In Biology, a mutation happens when

the DNA sequence of an individual is changed

For example, if …ACG TGA CCA GGT CCG TGA

becameACG TGA CCG GGT CCG TGA

we would say that the A mutated to a G

What causes mutation?Mutation can be caused by a number

of things

ChemicalsRadiationUltraviolet lightVirusesRandom chance

Types of mutationsTwo categories of mutations:Gene mutations (affect 1 gene)

Point mutationsFrameshift mutationsSilent mutations

Chromosomal mutationsChange # or structure of whole

chromosome

Point mutationsPoint mutations affect just one nucleotide

(one “point”) Also called substitution mutations

For example,THE FAT RED CAT ATE THE RATcould mutate to…THE FAT RED HAT ATE THE RATEven though only one letter (nucleotide)

was changed, the sentence doesn’t say the same thing it did before

Frameshift mutationsFrameshift mutations involve changing the

spacing of the codons These can either be insertion or deletion mutations

For example…THE FAT RED CAT ATE THE RATcould mutate toTHE FAT EDC ATA TET HER ATorTHE FFA TRE DCA TAT ETH ERA TBy deleting the “R”, the entire sentence is

now complete nonsense.

Silent mutationsSome mutations

don’t have any effect at all.

For example, AUG UAC UCG GUAcould mutate to AUG UAC UCU GUAWhere is the

mutation? Did it have an

effect?

Silent mutationsOne of the benefits of having

multiple codons for each amino acid. Mistakes can happen, but they

won’t necessarily cause damage.

Study GuideYou have the rest of the period to

work on your Chpt. 13 study guide (Due Friday)

EXPECTATIONS: You must stay in your seat You can work with the people at your

table Voice level should be quiet, no yelling

across the room Ask Ms. D or classmates questions

now if you have any!