Wednesday , April 24, 2013

1. Wednesday, April 24, 2013 • Do Now: Sequence a mRNA strand from the DNA sequence TACCCGTTAGACGCAACCACT. Now, using the genetic code chart on page 211, determine the amino acid sequence. • Objective: Evaluate three ways point mutations can alter genetic material. • HW:Worksheet

2. Mutations A change in the genetic material of a cell. Good Bad Neutral

3. 2 Types • Germ cell mutations – Occurs in organisms germ cells. • Somatic mutations – Occurs in organisms body cells. Which ones can be passed to offspring?

4. Where Can Mutation Occur? • Gene Mutations- Involve large segments of DNA or a single nucleotide within a codon. • Chromosome Mutations- Either changes in the structure of a chromosome or the loss of an entire chromosome.

6. 2 Types of Gene Mutations Point Mutation • Substitution Frameshift Mutation • Insertions • Deletions

7. THECATSAWTHEDOG THE CAT SAW THE DOG Sentence = Gene Word = Codon Letter = Nucleic base

8. THE BAT SAW THE DOG 2. THE CAT SAW THE HOG 3. THE CAT SAT THE DOG

9. THE ATS AWT HED OG

10. THE CMA TSA WTH EDO G

11. Frameshift Mutations THE CAT SAW THE DOG THE ATS AWT HED OG THE CMA TSA WTH EDO G

12. Frameshift Mutations • Caused by insertion or deletions of a nucleotide. • Alters the triplet grouping of nucleotides into codons. 3. Shifts the reading frame so that all nucleotides downstream will be improperly grouped.

13. Sickle Cell Mutation DNA mRNA Amino Acid Normal C G T → A Glutamic Acid T A Substitution C G A → T Valine T A

14. Check Point 1. Which type of mutation would have a greater effect on the sequence of amino acids in a protein, a base pair substitution or a frameshift mutation? Explain. 2. What is the maximum number of amino acids that could be coded for by a section of mRNA with the sequence GUUCAGAACUGU.

15. Chromosome Mutations • Are changes in chromosome structure. • There are four types of mutations: • Deletion- a piece breaks off and is lost. • Duplication - A piece is repeated. • Inversion - A piece breaks off and reattaches in the wrong order. • Translocation – A piece attaches to a different chromosome.

19. Karyotype

22. Structure of a chromosome