Topic 2

• Key eukaryotic cell organelles


  • Nucleus
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Mitochondria
  • Ribosomes
  • Vacuole
  • Chloroplasts
  • Cell wall
  • Plasma membrane
• Nucleus


  Where DNA replication occurs and mRNA is made, contains the genetic code
• Nucleolus


  Site of rRNA production and ribosome assembly
• Rough endoplasmic reticulum (RER)


  Site of protein synthesis due to ribosomes on the outside
• Smooth endoplasmic reticulum (SER)

  Site of lipid and carbohydrate synthesis and storage
• Golgi apparatus


  Modifies, packages and distributes molecules
• Lysosomes


  Bags of digestive enzymes involved in phagocytosis
• Mitochondria


  Site of aerobic respiration and ATP production
• Ribosomes


  Site of protein synthesis, found in both prokaryotic and eukaryotic cells
• Vacuole


  Fluid-filled structure that provides support and stores substances in plant cells
• Chloroplasts


  Site of photosynthesis in plant cells
• Cell wall


  Provides structural strength and prevents bursting in plant and fungal cells
• Plasma membrane


  Controls what can enter and exit the cell
• Prokaryotic cells are much smaller, lack membrane-bound organelles, and have a single loop of DNA instead of a nucleus
• Viruses are acellular and non-living, consisting of genetic material, a capsid, and attachment proteins
• Viruses replicate inside host cells
• Methods of studying cells

  • Microscopes
  • Cell fractionation and ultracentrifugation
• Magnification


  How many times larger the image is compared to the object
• Resolution


  Minimum distance between two objects where they can still be viewed as separate
• Optical microscopes


  • Use a beam of light, have lower resolution, can view living samples, produce color images
• Electron microscopes


  • Use a beam of electrons, have higher resolution, cannot view living samples, produce black and white images
• Cell fractionation


  1. Homogenization to break open cells

  2. Ultracentrifugation to isolate organelles by density
• Eukaryotic cells divide by mitosis or meiosis, while prokaryotic cells replicate by binary fission
• Stages of the eukaryotic cell cycle


  • Interphase (G1, S, G2)
  • Mitosis
  • Cytokinesis
• Mitosis


  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase
• Mitosis produces genetically identical cells through a single round of division
• Host cell


  The cell that uses the genetic material to replicate the virus particle
• Eukaryotic cell cycle


  1. Interphase

  2. Mitosis
• Interphase


  The longest stage of the cell cycle
• Stages of interphase


  • G1
  • S
  • G2
• G1


  The cell is increasing in size and the organelles will double
• S phase


  DNA replication happens
• G2


  Further growth and preparation for mitosis, includes an error check stage
• Nuclear division


  Mitosis or meiosis
• Cytokinesis


  The cytoplasm divides to create two new cells
• Stages of mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Mitosis


  • Only one round of division
  • Genetically identical cells are created
  • Cells are diploid (two copies of every chromosome)
  • Used for growth and repair
• Clonal expansion of B cells is an example of growth through mitosis
• Prophase


  1. Chromosomes condense and become visible

  2. Centriole pairs move to opposite poles

  3. Spindle fibers form from centrioles and attach to centromeres and chromatids
• Metaphase


  1. Chromosomes line up along the equator

  2. Spindle fibers attach to centromeres and chromatids