Chapter 8.22-8.23 Mutations PDF

“When you get to the end of your rope, tie a knot and hang on.” Franklin D. Roosevelt CH. 8.22 - 8.23 Mutations LEARNING OBJECTIVES Today you will learn to: Provide examples of mutations that are lethal, harmful, and beneficial. Understand why the tenants of the...

“When you get to the end of your rope, tie a knot and hang on.” Franklin D. Roosevelt CH. 8.22 - 8.23 Mutations LEARNING OBJECTIVES Today you will learn to: Provide examples of mutations that are lethal, harmful, and beneficial. Understand why the tenants of the traditional cell theory have been expanded to the modern cell theories. UNIT ORGANIZER DNA is about The Code of Life the its Historical function its to Experiments how it is to discover it Make Proteins Structure Replicated for cell through division Translation Transcription Shape Components  What is a mutation?  Any change in the order of the genetic code.  What do you think a point mutation is?  A mutation that affects one nucleotide KINDS OF MUTATIONS  Mutations that produce changes in a single gene are known as gene mutations.  Mutations that produce changes in whole chromosomes are known as chromosomal mutations. KINDS OF MUTATIONS Gene Mutations  Gene mutations involving a change in one or a few nucleotides are known as point mutations because they occur at a single point in the DNA sequence.  Point mutations include substitutions, insertions, and deletions. KINDS OF MUTATIONS Substitutions usually affect no more than a single amino acid. KINDS OF MUTATIONS The effects of insertions or deletions are more dramatic. Copyright Pearson Prentice Hall  They can result in frameshift mutations  Occur when an addition or deletion of a nucleotide shifts the grouping of codons and causes entire codons to be read incorrectly. KINDS OF MUTATIONS In an insertion, an extra base is inserted into a base sequence. KINDS OF MUTATIONS In a deletion, the loss of a single base is deleted and the reading frame is shifted. KINDS OF MUTATIONS Chromosomal Mutations  Chromosomal mutations involve changes in the number or structure of chromosomes.  Chromosomal mutations include deletions, duplications, inversions, and translocations. 12-4 MUTATIONS SIGNIFICANCE OF MUTATIONS  Mutation = any change in DNA  Mutations are the ULTIMATE SOURCE OF NEW VARIATION IN SPECIES!  Many mutations have little or no effect on gene expression.  Some mutations are the cause of genetic disorders.  Produce defective proteins (cancer) SIGNIFICANCE OF MUTATIONS  Mutations can happen randomly, as in this Scottish fold cat. Cat enthusiasts bred these cats from a single cat with a mutation for the ear fold. SIGNIFICANCE OF MUTATIONS  Mutations can be beneficial too  Source of genetic variability in species  New genotypes that express new phenotypes  Could be useful in new or changing environments EVOLUTION CONNECTION: NEW SPECIES CAN ARISE FROM ERRORS IN CELL DIVISION  Errors in mitosis or meiosis may produce polyploid species, with more than two chromosome sets.  The formation of polyploid species is  widely observed in many plant species but  less frequently found in animals. © 2015 Pearson Education, Inc.  SIGNIFICANCE OF MUTATIONS  Plants can regularly be bred to have multiple sets of chromosomes.  They are larger and stronger than normal plants  Ex. day lilies, bananas, citrus fruits FIGURE 8.22 Rarely, polyploidy can occur in vertebrates, such as in this frog. SIGNIFICANCE OF MUTATIONS  Scientists can increase genetic variation by inducing mutations  Can use radiation and chemicals to produce them  Can occur spontaneously 20  SIGNIFICANCE OF MUTATIONS  Mutationsproduce new kinds of bacteria  ex. oil-eating bacteria used in bioremediation to clean up oil spills. AND NOW WE MUST RETURN TO THE CELL THEORY. MODERN RESEARCH HAS ADVANCED THE CELL THEORY FROM THE TRADITIONAL… THE TRADITIONAL CELL THEORY **You still need to know these for upcoming tests and the SOL!! 1. Living things are composed of one or more cells and that cells come from other cells by the process of cell reproduction. 2. Cells are the basic unit of structure and function in living things. 3. Cells contain specialized structures to perform functions necessary for life. TO THE MODERN… THE MODERN CELL THEORY 1. Energy flow (metabolism and biochemistry) occurs within cells. 2. Cells contain hereditary information (DNA) that is passed from cell to cell during cell division. 3. All cells are basically the same in chemical composition of similar species. IT WAS 1665 WHEN CELLS WERE FIRST NAMED BY ROBERT HOOKE, AND THE 1800’S WHEN SCHLEIDEN, SCHWANN AND VIRCHOW STUDIED CELLS… WE NOW UNDERSTAND ENOUGH OF THE CODE OF LIFE TO GENETICALLY ENGINEER NEW COMBINATIONS… WHO KNOWS WHAT FUTURE RESEARCH WILL UNCOVER… SECTION REVIEW 1. Provide examples of mutations that are lethal or harmful. 2. Explain why the tenants of the traditional cell theory have been expanded to the modern cell theory.