M3 BIOLAB

• Types of Cells


  • Prokaryotic Cell
  • Eukaryotic Cell
• Prokaryotic Cell


  • Unicellular organisms that do not develop or differentiate into multicellular forms
  • Identical and capable of independent existence
  • Lack a nucleus and membranous organelles
• Prokaryotic Cell


  Include all bacteria and archaea (archaebacteria)
• Eukaryotic Cell


  • Contain a nucleus and membrane-bound compartments, called organelles, in which specific metabolic activities take place
  • Include fungi, animals, and plants as well as some unicellular organisms
• Parts of a Eukaryotic Cell

  • Cell membrane
  • Cytoplasm
  • Cytosol
  • Organelles
  • Nucleus
• Cell membrane


  Controls what gets in and out of the cell
• Cytoplasm


  The living substance of the cell
• Cytosol


  The fluid portion of the cell's cytoplasm where a major part of cellular metabolism takes place
• Organelles


  • Endoplasmic Reticulum
  • Mitochondrion
  • Golgi Complex
  • Lysosomes
  • Peroxisome
• Endoplasmic Reticulum


  • Concerned with intracellular transport
  • Smooth Endoplasmic Reticulum is the site for the synthesis of cholesterol and phospholipids, and involved in the transport of fatty acids and other lipids
  • Rough Endoplasmic Reticulum receives proteins that are synthesized by ribosomes
• Mitochondrion


  • Also known as the powerhouse because they release energy for the cell
  • ATP generation happens in the MATRIX
  • Undergoes self replication in a manner similar to bacterial cell division
  • Contains a DNA
• Golgi Complex


  • Stacked, flattened membranes
  • Transports substance to and from the cell
  • Modifies, packages and transports protein
  • Produces lysosomes
• Lysosomes


  • Simple tiny spherical sac-like structures
  • Surrounded by a single membrane and contains powerful enzymes capable of digesting or breaking down all organic materials
  • Known as suicide bags
• Peroxisome


  • Breaks down hydrogen peroxide into water and oxygen
  • Detoxification of alcohol and other toxic compounds
• Nucleus


  • A rounded structure at the center of the cell that controls the metabolic activities
  • Contains the DNA
  • Frequently the largest structure in the cell
• The cell membrane serves as a clear boundary between the cell's internal and external environment
• Cell membrane


  • Also called plasma membrane or plasmalemma
  • Semi-permeable with a framework of fat-based molecules called phospholipids, which prevent hydrophilic substances from entering or escaping the cell
• Parts of the Cell Membrane

  • Phosphate head (polar, hydrophilic)
  • Fatty Acid Tail (non-polar, hydrophobic)
  • Proteins (transmembrane, integral, peripheral)
• Function of the Cell Membrane

  • Delimits the cell from its surroundings
  • Controls what gets in and out of the cell
  • Provides attachment for the skeleton of the cell
  • Receives and sends out stimuli
  • Provides binding sites and receptors for enzymes and other substances
  • Allows cell-to-cell recognition
  • Forms specialized junctions with cell membrane of adjacent cells
• Proteins are crucial to membrane function
• Types of Transport


  • Active (requires energy, goes against the concentration gradient)
  • Passive (does not require energy, goes with the concentration gradient)
• Simple Diffusion


  Diffusion is the random movement of molecules from an area of high concentration to low concentration, and requires no energy
• Molecules that diffuse through cell membranes

  • Oxygen (non-polar, diffuses very quickly)
  • Carbon dioxide (polar but very small, diffuses quickly)
  • Water (polar but also very small, diffuses quickly)
• Osmosis

  The diffusion of water across a membrane, moving from high water concentration to low water concentration
• Cells in Solutions

  • Isotonic (solute concentration is the same as inside the cell)
  • Hypotonic (solute concentration is lower than inside the cell)
  • Hypertonic (solute concentration is higher than inside the cell)
• Cytolysis


  Cell bursting in a hypotonic solution
• Plasmolysis


  Cell shrinking in a hypertonic solution
• Facilitated Diffusion


  Does not require energy, uses transport proteins to move high to low concentration
• Types of Transport Proteins

  • Channel proteins (embedded in the cell membrane with a pore for materials to cross)
  • Carrier proteins (can change shape to move material from one side of the membrane to the other)
• Active Transport


  Requires energy or ATP, moves materials from low to high concentration, against the concentration gradient
• Active Transport


  • Sodium-Potassium Pump
• Exocytosis


  Molecules are moved out of the cell by vesicles that fuse with the plasma membrane
• Forms of Endocytosis


  • Pinocytosis
  • Receptor-mediated endocytosis
  • Phagocytosis
• Prokaryotic Cell


  A type of cell that does not have a true nucleus or membrane-bound organelles, and divides by binary fission.
• Eukaryotic Cell


  A type of cell that has a true nucleus and membrane-bound organelles, and divides by mitosis.
• Nucleus


  A membrane-bound organelle present in eukaryotic cells that contains DNA and directs cellular activities.
• Membrane-bound organelles


  Structures found in eukaryotic cells that are surrounded by a lipid bilayer and perform specific functions, such as mitochondria and chloroplasts.
• DNA


  In prokaryotic cells, DNA is present in the cytoplasm, while in eukaryotic cells, DNA is present in the nucleus.
• Cell division


  Prokaryotic cells divide by binary fission, while eukaryotic cells divide by mitosis.
• Size


  Eukaryotic cells are generally larger than prokaryotic cells.