Week 2: Cellular Elements

• Cell


  Basic unit of life
• Cell history


  • Robert Hooke (1665) - used a microscope to examine cork (plant) and called what he saw "cell"
  • Anton Van Leeuwenhoek (1674) - Father of Microbiology, discovery containing protozoa, RBC capillary systems, and life of insects
  • Robert Brown (1833) - discovered the nucleus
  • Dujardin (1835) - discovered that cells were not empty, but filled with thick jelly-like fluid
  • Matthias Schleiden (1938) - All plants are composed of cells
  • Rudolf Virchow (1855) - "Cells only come from other cells", "theory of spontaneous generation"
  • Theodor Schwann (1838) - Discovered that animals were made of cell
• Cell theory


  1. All living things are composed of cells

  2. Cells are basic unit of life

  3. All cells come from pre-existing cells
• Types of cells


  • Prokaryotic - do not have structures surrounded by membranes, one-celled organisms, few internal structures

  Eukaryotic - contains organelle, surrounded by membranes, most living organisms
• Animal cell components


  • Plasma cell membrane

  Endoplasmic reticulum

  Nucleus: largest organelle

  Ribosome

  Golgi

  Mitochondria

  Lysosome
• Cell membrane


  Controls movement in and out of the cell, double layer, outer membrane, lipid bilayer
• Types of endocytosis


  • Phagocytosis

  Pinocytosis

  Receptor-mediated endocytosis
• Cell wall


  Found in plant cells and bacteria, supports and protect cells
• Nucleus


  Directs cell activities, contains genetic material (DNA), separated from cytoplasm by nuclear membrane
• Nuclear membrane


  Surrounds nucleus, made of 2 layers
• Chromosomes


  In nucleus, made of DNA, contain instructions for traits and characteristics
• Nucleolus


  Inside nucleus, contains RNA to build proteins
• Cytoplasm


  Gel-like mixture, contains hereditary materials, surrounded by cell membrane
• Endoplasmic reticulum


  • SMOOTH - lacks ribosomes

  ROUGH - Ribosomes embedded in surface

  Functions: Synthesis, Transport, Storage, Detoxification
• Ribosomes


  Make proteins, found on ribosomes and floating throughout the cells
• Mitochondria


  Produces energy through chemical reactions, controls level of water and other material in cell, recycles and decomposes proteins, fats, and carbohydrates, powerhouse of the cell
• Golgi bodies


  "Protein packaging plant", materials within and out of the cell
• Lysosomes


  Digestive plant for proteins, fats, and carbohydrates, transports undigested material to some membrane, "suicide bags" - cell breaks down if lysosomes explodes
• Mitosis


  Duplication - must first copy its DNA

  The copies must be separated, and sorted into two sides of the cells

  The cells will split in 2

  Results in such as internal organs: skins or bones

  Two daughters sells similar to parents
• Meiosis


  Should copy the DNA

  Results in reproductive cells

  Part of each parent is carried to the four new cells

  Creates genetic diversity
• Mitosis vs Meiosis


  Mitosis takes cells & Makes It Two (diploid)

  Meiosis has to do with sexual reproduction

  Mitosis results in Identical Twins

  Meiosis = egg & sperm (haploid)
• Diploid


  46 chromosomes, undergo mitosis
• Haploid


  23 chromosomes
• Interphase


  DNA is replicated along with organelles and other cellular components
• Prophase


  The DNA recoils and chromosomes condensed, nuclear membrane disappears in mitotic spindles begins
• Metaphase


  Chromosomes lineup in the middle of the cell with the help of spindle fibers
• Anaphase


  Chromosomes split in the middle and sister chromatids are pulled by spindle fibers
• Telophase


  Chromosomes along with cytoplasm, and its organelles and membranes are divided into two portions
• Cytokinesis


  Actual splitting
• Meiotic division one


  The homologous chromosomes are separated
• Meiotic division two


  The sister chromatids are separated
• Meiosis interphase


  Preceded by interphase, chromosomes have not yet condensed, chromosomes replicated, and the chromatin begin to condense
• Meiosis Prophase I


  Chromosomes are completely condensed, the homologous chromosomes spare with one another
• Meiosis Prophase II


  Cell divided into two daughter cells
• Meiosis Metaphase I


  Nuclear membrane dissolves and homologous attached to spindle fibers, preparing to go to opposite poles
• Meiosis Metaphase II

  Chromosomes lineup on the spindle fiber
• Meiosis Anaphase I


  Chromosomes moved to opposite end of the cell
• Meiosis Anaphase II


  Two cells each begin to divide, chromosomes moved to opposite end of each cell
• Meiosis Telophase I & Cytokinesis


  Cell divided into two daughters cell, each daughter cells get any combination of maternal and paternal chromosomes
• Meiosis Telophase II & Cytokinesis


  Non-identical cells, four cells, meiosis is over