September 5, 2017 www.biohs.weebly.com TO DO: Notebook, pencil/pen. WARM UP: How do cells reproduce? HOMEWORK: Lab Report Due September 11th www.biohs.weebly.com
Phases of the Cell Cycle The cell cycle consists of Interphase – normal cell activity The mitotic phase – cell divsion INTERPHASE Growth G 1 (DNA synthesis) Growth G2 Cell Divsion
Functions of Cell Division 20 µm 100 µm 200 µm (a) Reproduction. An amoeba, a single-celled eukaryote, is dividing into two cells. Each new cell will be an individual organism (LM). (b) Growth and development. This micrograph shows a sand dollar embryo shortly after the fertilized egg divided, forming two cells (LM). (c) Tissue renewal. These dividing bone marrow cells (arrow) will give rise to new blood cells (LM).
Chromosomes A diploid cell has two sets of each of its chromosomes A human has 46 chromosomes (2n = 46) In a cell in which DNA synthesis has occurred all the chromosomes are duplicated and thus each consists of two identical sister chromatids Maternal set of chromosomes (n = 3) Paternal set of 2n = 6 Two sister chromatids of one replicated chromosome Two nonsister chromatids in a homologous pair Pair of homologous chromosomes (one from each set) Centromere
Phases of the Cell Cycle Interphase G1 - primary growth S - genome replicated G2 - secondary growth M - mitosis C - cytokinesis
Interphase occurs before mitosis begins Chromosomes are copied (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm
Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase 1st step in Mitosis Mitosis begins (cell begins to divide) Centrioles (or poles) appear and begin to move to opposite end of the cell. Spindle fibers form between the poles. Centrioles Sister chromatids Spindle fibers
Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase 2nd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers. Centrioles Spindle fibers
Metaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase 3rd step in Mitosis Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers
Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase 4th step in Mitosis Two new nuclei form. Chromosomes appear as chromatin (threads rather than rods). Mitosis ends. Nuclei Nuclei Chromatin
Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Cytokinesis occurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.
Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
Cell Cycle
- Cell Division The Cell Cycle 20
Cell Division An integral part of the cell cycle Results in genetically identical daughter cells Cells duplicate their genetic material Before they divide, ensuring that each daughter cell receives an exact copy of the genetic material, DNA
Vocabulary Go to your website and write this in your journal page. Mitosis Vocabulary. Dictionary definition Your own definition Write it in a sentence
Vocabulary Mitosis Vocab: Interphase: G1 phase, S phase, G2 phase Prophase Metaphase Anaphase Telophase Cytokinesis Chromosome Chromatid Centriole