- Slides: 8
The Cell Cycle/Mitosis & Meiosis Notes
Let’s review the cell cycle! What percentage of time do cells spend in Interphase? Up to 90% What are three phases of interphase? G 1, S and G 2
Meiosis Parent Cell 2 Daughter cells 4 Daughter cells
What’s the difference? How many daughter cells are produced? Mitosis produces 2 identical daughter cells Meiosis produces 4 genetically different daughter cells
What’s the difference? • Mitosis creates body (somatic) cells needed for growth or to repair/replace other cells that have been damaged or worn out • Meiosis creates gametes (sex cells) for reproduction.
What’s the difference? • Mitosis –crossing over DOES NOT occur • Meiosis –crossing over OCCURS • Crossing over- the exchange of genetic material between homologous chromosomes to increase genetic diversity in offspring •
What’s the difference? • The cells created from mitosis are diploid. • The cells created from meiosis are haploid Definitions: Diploid – full set-two of each type of chromosome (in homologous pair – carry the same trait) ex-in humans= ? ? Haploid – half a set-one of each type of chromosome ex- in humans= ? ?
Why are gametes haploid? • Gametes must be haploid (contain half the number of chromosomes) so that when the reproductive cells (sperm and eggs) combine, the organism produced will have the correct number of chromosomes.