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 like glycoproteins, secretory enzymes, carbohydrates, lipids
• Lysosomes


  Bags of digestive enzymes involved in phagocytosis and exocytosis
• 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
• Key differences between prokaryotic and eukaryotic cells

  • Prokaryotes are smaller
  • Prokaryotes lack membrane-bound organelles
  • Prokaryotes have 70S ribosomes
  • Prokaryotes have circular DNA
  • Prokaryotes may have cell walls and capsules
  • Prokaryotes may have flagella
• Viruses


  Acellular and non-living, consist of genetic material, capsid, and attachment proteins, 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
• Types of microscopes


  • Optical (light)
  • Transmission electron
  • Scanning electron
• Optical microscopes


  Use a beam of light to create the image, have lower resolution due to longer wavelength of light
• Electron microscopes


  Use a beam of electrons to create the image, have higher resolution due to shorter wavelength of electrons
• Eyepiece graticule


  Scale within the optical microscope used to measure the size of specimens
• Cell fractionation


  1. Homogenization to break open cells

  2. Differential centrifugation to isolate organelles based on density
• Conditions for cell fractionation: cold, isotonic, buffered
• Order of organelle isolation by density


  • Nuclei
  • Chloroplasts and mitochondria
  • Lysosomes and ER
  • Ribosomes
• Eukaryotic cells divide by mitosis or meiosis, prokaryotic cells replicate by binary fission, viruses replicate inside host cells
• Stages of the eukaryotic cell cycle


  • Interphase (G1, S, G2)
  • Mitosis (Prophase, Metaphase, Anaphase, Telophase)
  • Cytokinesis
• Mitosis


  • One round of division, produces genetically identical cells, diploid cells
• 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