1 / 12

Cell Division

Cell Division. Mitosis and Meiosis. Recall A Few Main Things. All new cells come from existing cells DNA is stored in the nucleus of cells in eukaryotes. Chromosomes. A chromosome is a single, very long, strand of DNA Each chromosome contains many thousands of genes. Diploidy.

haracha
Télécharger la présentation

Cell Division

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Division Mitosis and Meiosis

  2. Recall A Few Main Things • All new cells come from existing cells • DNA is stored in the nucleus of cells in eukaryotes

  3. Chromosomes • A chromosome is a single, very long, strand of DNA • Each chromosome contains many thousands of genes

  4. Diploidy • Each species has a set # of chromosomes • We also have 2 versions of each chromosome (called homologous chromosomes) • I.e. humans have 23 sets of chromosomes, or 46 total

  5. Types of Cell Division • Usually when we make new cells, we want them to be identical to existing cells • i.e. make new skin cells from existing ones • The new cell is completely identical

  6. Mitosis • Cell division that creates identical daughter cells • So the new cell has the exact same chromosomes as the original cell

  7. The Extent of Mitosis • Almost every single cell in our body is made from mitosis • Exceptions: the first cell, sperm/egg cells • When we grow new skin, new hair, new muscles – all of that is mitosis • So every cell in our body has the exact same set of chromosomes

  8. Sperm/Egg • You pass on half your genes to offspring • You must make a gamete (sperm or egg cell) with half of your chromosomes • Each gamete randomly receives 1 of the 2 versions of each chromosome

  9. Meiosis • Each parent cell produces 4 daughter cells • Each daughter cell has 1 set of chromosomes (half of the parent’s chromosomes) • (is haploid)

  10. # of Possible Gametes • There are 223 possible chromosome combinations to make a gamete • =8,388,608 possibilities • So you are 1 out of 8,388,6082 possibilities • You are quite literally 1 in a trillion (1 of 70,368,744,200,000 possible combinations of your parents)

  11. Mitosis Meiosis • Identical offspring (same set of chromosomes) • 2 daughter cells • Creates all body cells • Produces diploid cells • Offspring have half as many chromosomes • 4 daughter cells • Creates sperm/egg • Produces haploid cells Mitosis vs. Meiosis

  12. What’s the Point? • Meiosis allows us to have offspring that are different and have a unique combination of genes • This increases diversity in the population • Increased diversity means increased ability for the species to survive and adapt to new situations

More Related