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Mutations November 1+1, 2009

Mutations November 1+1, 2009. Objectives: By the end of today, you will be able to define a mutation and explain how they contribute to variation. Catalyst: When you hear the word mutation, what do you think of? Write at least three complete sentences. Agenda . Catalyst Review Mutations

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Mutations November 1+1, 2009

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  1. MutationsNovember 1+1, 2009 • Objectives: • By the end of today, you will be able to define a mutation and explain how they contribute to variation. • Catalyst: • When you hear the word mutation, what do you think of? Write at least three complete sentences.

  2. Agenda • Catalyst Review • Mutations • Variations • Independent Practice • Exit Question

  3. Alright: New Unit!!! Evolution • We are beginning a two-week unit about evolution. We are going to learn some things such as: • Why do some people have lighter skin and other have darker skin? • Why would a cuckoo bird lay her eggs in another birds’ nest? • Why did white moths become less common and gray moths become more common near a factory? • The answer can all be found in evolution!

  4. Introduction/Bridge • Evolution is DIRECTLY related to genetics. • The traits of all living things are found in their DNA/chromosomes. • Why are there differences between people? Why are there any differences among the individuals of any living thing?

  5. Mutations • Key Point #1 • A mutation is a change in the sequence of DNA. They can be good, bad, or not matter at all. • Example: • The gene for making insulin (a protein that regulates your blood sugar), could have the DNA sequence of GTA-CGT-ACC-GTA-ACT…

  6. Figure it out yourself! (10 mins) • You need your codon tables from the genetics unit • First, circle the difference in each mutation from the original • After you finish, answer the question… • Which mutation would cause the biggest change?

  7. Why does that matter? DNA • Your DNA has instructions to make the proteins!!!! • Changes in your DNA are copied into your RNA. • That faulty RNA is used to pick the amino acids in your protein. • What could possibly happen if you have the wrong amino acids???? RNA Protein

  8. Correct Protein 1 • Original correct DNA sequence: • GTA-CGT-ACC-GTA-ACT • Makes mRNA: CAU-GCA-UGG-CAU-UGA • Make amino acid sequence: Histidine-Alanine-Tryptophan-Histidine-STOP • This makes the protein which can reliably allow your body cells to take in more sugar or release sugar in order to maintain a good blood sugar level.

  9. Messed Up Protein 1 • Mutated DNA sequence 1: (switching one base) • GTA-CGT-ACC-GTC-ACT • CAU-GCA-UGG-CAG-UGA  RNA! • Makes amino acid sequence: Histidine-Alanine-Tryptophan-Glutamine-STOP

  10. Messed Up Protein 2 • Another mutated DNA sequence: (switching one base that makes a STOP codon) • GTA-CGT-ACT-GTC-ACT • CAU-GCA-UGA-CAG-UGA • Makes amino acid sequence: Histidine-Alanine-STOP

  11. Messed Up Protein 3 • Even more mutated DNA sequence: (insertions) • GTACGTACACGTAACT • GTA-CGT-ACA-CGT-AAC-T • CAU-GCA-UGU-GCA-UUG-A  RNA! • Makes amino acid sequence: Histidine-Alanine-Cysteine-Alanine-Leucine

  12. Mutations • Key Point #2 • Mutations occur randomly in the DNA of living organisms and this causes variation. • They cause traits to be slightly different from each other. • Variation is the differences among individual phenotypes. • Example: • Eye color in humans.

  13. More Variation Examples • Quickness in gazelles. • Leaf Size for a tea plant

  14. It’s all about the babies • Key Point #3 • Mutations can either increase fitness, decrease fitness, or not change fitness • What do you think fitness means? • Amount of muscles? • NO! • Heart rate? • NO! • How many kids you have? • YESSSS!!!!! Fitness: ability of an organism to pass its genes on to the next generation.

  15. Practice! • There is a mutation that causes fur color in bears to become white. • When would this increase fitness and why? • In snowy areas, this would increase fitness because these bears would be able to hide easier. They could catch more prey, live longer, and reproduce more. • When would this decrease fitness and why? • In darker areas (such as the forest), this would decrease fitness because these bears would stand out. They would not be able to live as long and then they would reproduce less. • When would this not change fitness? • If the bear was in an area where it did not need to hide, it may not change fitness. This would change how much they reproduce.

  16. Practice • There is a mutation that causes rabbits to have longer ears. • When would this increase fitness? • When would this decrease fitness? • When would this not change fitness?

  17. Practice • There is a mutation that causes trees to grow shorter. • When would this increase fitness? • When would this decrease fitness? • When would this not change fitness?

  18. Exit Question • What is a mutation? • How do mutations contribute to variation?

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