Cell division, diversity and organisation

Cell division, diversity and organisation

1. Mitosis

   • Cell cycle consists of cell growth call interphase, and cell division called mitosis
     • During interphase, genetic material is copied and checked for errors, if there are errors the cell will kill itself to prevent mutations
   • Interphase: Genetic material is unravelled and copied and organelles are are replicated
   • Prophase: Chromosome condense, short and fat. Centrioles move to opposite ends and form the spindle. Nuclear envelope breaks down and chromosomes are in cytoplasm
   • Metaphase: Chromosomes line up along the middle and are attached by the spindle.
   • Anaphase: Centromeres divide and seperate the sister chromatids. Spindles contract pulling the centromere first/
   • Telophase:Nuclear envelope forms around the group of chromosome and cytoplasm divides.

2. Division and reproduction

   • Budding in yeast (asexual)
     • A bud forms at the surface, it undergoes interphase then mitosis. It then seperates from the the parent cell.
   • Meiosis creates genetically different cells. They start off with the full number of chromosomes but end up with half.
   • Homologous pair: One maternal and one paternal, same size and same genes

3. Stem cells and differentiation

   • Stem cells are unspecialised cells that can develop into any type of cell
   • Cells in bone marrow can differentiate to produce erythrocytes and neutrophils.
     • Cells in cambium differentiate into xylem and phloem
   • Animal cells
     • Neutrophils
     • Eythrocytes
     • Epithelial cells
     • Sperm cells
   • Plant cells
     • Palisade mesophyll cells
     • Root hair cells
     • Guard cells

4. Tissues, organs, systems

   • Squamous Epithelium
     • Single layer of flat cells lining a surface
   • Xylem tissue
     • Transports water and supports the plant
   • Phloem tissue
     • Transports sugars, contains sieve cells, companion cells and plant cells. End walls called sieve plates
   • Ciliated epithelium
     • Layer of cells covered in cilia.
   • Similar cells make a tissue. Different tissues make an organ and different organs make an organ system.
   • System of cooperation; transport system and communication system