Todays outline… Please pick up Notes/worksheet/your activity from yesterday Attendance Update: Blog – how to access Review yesterday’s Activity Todays lesson – Mutations: Causes and Effects Mutations in a cup activity Practice questions Worksheet – homework if not

Mutations: Causes and Effects

What Are Mutations? Sometimes cells make mistakes when copying their own DNA Def: Mutations are changes in the genetic material The chances of a mutation occurring can be increased by chemical or physical factors

What Are Mutations? Gene mutations These mutations involve a change in one or a few nucleotides and affect a single gene

WHAT ARE MUTATIONS Point Mutations happen at a single point in the DNA. They include Substitutions – one nitrogen base is changed to another Insertions – an additional base is inserted into the DNA sequence Deletions – a base is removed from the DNA sequence

What Can We Observe About Mutations? At the end of your bench is a pot of numbered papers At random select 4 (one for each person in your group) from the pot Record the outcome of your mutation in a small table Round Environment Mutation Effect

What Can We Observe About Mutations? Round 1: Flu Epidemic Colour Mutation 1 Able to fight off infection better 2 No mutation 3 4 Less able to fight off infection 5 No effect

What Can We Observe About Mutations? Round:1 Intense sunshine and water shortage Number Mutation 1 No effect 2 Prone to dehydration and sunstroke 3 4 No mutation 5 Better able to store water and keep cool

What Can We Observe About Mutations? Round 3: Heavy metal pollution Number Mutation 1 Able to fight off infection better 2 No effect 3 No mutation 4 Less able to fight off infection 5

What Can We Observe About Mutations? Round 4: Malaria outbreak Number Mutation 1 Prevents infection from “taking hold” 2 No mutation 3 4 Less able to fight off infection 5

What Can We Observe About Mutations? Round 3: HIV Epidemic Number Mutation 1 Immune to infection 2 No mutation 3 Immune system severely compromised 4 Less able to fight off infection 5

What Can We Observe About Mutations? Some guiding questions Do mutations target specific individuals or genes? In what ways do mutations effect living organisms? What determines if an effect is good or bad?

What Are Mutations? The effects of a mutation on an organism can be: Positive – results in genetic diversity and may have huge benefits for an organism Neutral – results in little or no change in gene expression Negative – affects gene expression and protein production. May be very harmful to an organism The effect a mutation has will depend on the environment

Gene Mutations: Substitution Only affects one amino acid

Gene Mutations: Insertion

GENE MUTATIONS: Deletion

Check for Understanding: List the three types of gene mutations Substitution Insertion Deletion Based on what you know of mutations which of the three gene mutations do you think is the most likely to cause harm to an organism and why? Hint: Think of our sentences – what would affect them more? Deletion and/or insertion – these mutations can cause changes to multiple amino acids and can affect protein shape and function Group Practice

GENE MUTATIONS: Frameshift Deletion and insertion mutations are known as FRAMESHIFT mutations Can affect the way the triplet code is read This can affect the amino acid sequence and may alter the protein Proteins may become unable to perform their function

WHAT ARE MUTATIONS THE FAT CAT ATE THE RAT THE FAT HCA TAT ETH ERA T Examples of Frameshift Mutations: Insertion: In these examples the words represent amino acids and the sentence represents the protein THE FAT CAT ATE THE RAT THE FAT HCA TAT ETH ERA T Remember we must still follow the triplet code even after mutation – all the triplets that follow the insertion have been frameshifted

WHAT ARE MUTATIONS THE FAT CAT ATE THE RAT TEF ATC ATA TET GER AT Examples of Frameshift Mutations: Deletion: In these examples the words represent amino acids and the sentence represents the protein THE FAT CAT ATE THE RAT TEF ATC ATA TET GER AT Remember we must still follow the triplet code even after mutation – all the triplets that follow the insertion have been frameshifted

Mutagens and Carcinogens Def: A mutagen is any physical or chemical factor that causes changes (mutations) to an organisms DNA Chemical Mutagens: Air fresheners Alcohol Cosmetics Pesticides Physical Mutagens: X-rays UV rays

EXAMPLES OF MUTATIONS Color blindness – mutation on the X chromosome. Very common in males, not common in females Sickle Cell Anemia – reduces bloods ability to carry oxygen Blue eyes – A mutation that occurred 6000-10,000 years ago. All blue eyed people share a common ancestor! Down Syndrome – Mutation resulting in extra chromosomes