Grade 10A Biology Notes: 11.3 Genetic Changes (PDF)

Universal School of Lebanon Grade 10A Biology Notes 11.3 Genetic Changes  Mutation is any change in the DNA sequence.  Somatic or body cells 1. Play no role in reproduction. 2. Form the majority of cells in the body. 3. Divide...

Universal School of Lebanon Grade 10A Biology Notes 11.3 Genetic Changes  Mutation is any change in the DNA sequence.  Somatic or body cells 1. Play no role in reproduction. 2. Form the majority of cells in the body. 3. Divide by mitosis.  Reproductive or germ cells 1. Play a role in reproduction because upon their division, sex cells (gametes) can be produced. 2. Found in the testes of males & in ovaries of females. 3. Divide by meiosis.  A mutation is passed on to offspring if it affects the reproductive cells of an organism and not its somatic cells.  Cancer results when some mutations affect genes that control cell division.  Two types of mutations: 1. Gene mutations 2. Chromosomal mutations  Gene mutations are of two types: 1. Point mutations: A change in a single base pair in DNA Less harmful to an organism because they disrupt only a single codon 2. Frameshift mutations: A single base is added or deleted from DNA Nearly every amino acid after the insertion or deletion of a base is changed Sara Shamra  Unlike gene mutations, chromosomal mutations affect many traits. They are of four types: 1. Deletion 3. Inversion 2. Insertion 4. Translocation  Spontaneous mutations occur naturally without any inducing agent (can result from errors in DNA replication).  Induced mutations occur with any mutagen (agent that can cause a change in DNA).  Mutagens includes radiations, chemicals, and high temperatures. Sara Shamra