Cells (Lab)

• History of Cell Study

  • Robert Hooke - discovered cell
  • Anton Van Leeuwenhoek - famous in observing one celled organisms
  • RJH Dutrochet (1824) - all living things are made of cells and increase in size and divide (one of the first clear statement)
  • Dujardin (1835) - French zoologist recognized the universality of protoplasm within plant cells and named it
  • Max Schultz - called protoplasm the physical basis of heredity
  • Rudolf Virchow - studied the life of cells and concluded that "every cell comes from a pre-existing cell" (cell theory/doctrine)
• Significance of Cells


  • Unit of structure and function, function, growth, reproduction
  • Contain the units heredity
• Cell shape


  • Spherical
  • Polyhedral
  • Ovoid
  • Ellipsoid
  • Cylindrical
  • Tubular
  • Prismatic
  • Lamelliform
  • Fiber-like
  • Stellate
• Cell size


  • 1mm - parenchyma cells
  • 1-3 mm - fibers of wood & phloem of angiosperm
  • 2-8mm - fibers of wood & phloem of gymnosperm
  • 20-50mm - certain monocotyledon
• Prokaryotic Cell


  • Cell lacks true nucleus
  • 1-10 um in diameter
  • DNA is in a single chromosome located in the nucleoid region
  • Internal membrane does not compartmentalize with few organelles
• Eukaryotic cell

  • Have true nucleus
  • 10-100 um in diameter
  • Membrane-bound compartment that houses DNA within chromosomes
  • Organelles- small membranous bodies structure suits their functions
• ORGANELLES

  • Cell Wall
  • Plasma or Cell Membrane
  • Ribosomes / Microsomes
  • Endoplasmic reticulum
  • Golgi apparatus / Dictyosomes
  • Vacuoles and vesicles
  • Peroxisomes / Microbodies
  • Mitochondrion
  • Chloroplast
  • Cytoskeleton
  • Nucleus
• Cell Wall

  • Composition: cellulose fibrils
  • Function: for support and protection
• Plasma or Cell Membrane

  • Composition: Bilayer of phospholipids with embedded proteins
  • Function: passage of molecules into and out of the cell
• Ribosomes / Microsomes

  • Composition: proteins & RNA in 2 subunits (60 - 40)
  • Function: protein synthesis
• Endoplasmic reticulum

  • Composition: membranous flattened channels and tubular canals
  • Function: transport system, protein synthesis- rough ER
• Golgi apparatus / Dictyosomes

  • Composition: stack of membranous saccules
  • Function: processing and packaging of molecules, e.g. glycoproteins
• Vacuoles and vesicles

  • Composition: membranous sacs
  • Function: storage of substances
• Peroxisomes / Microbodies

  • Composition: membranous vesicle containing specific enzymes
  • Function: various metabolic tasks
• Mitochondrion

  • Composition: inner membrane (cristae) within outer membrane
  • Function: cellular respiration
• Chloroplast

  • Composition: inner membrane (grana) within 2 outer membrane
  • Function: photosynthesis
• Cytoskeleton

  • Composition: microtubules, microfilaments
  • Function: shape of cell and movements of its parts
• Nucleus

  • Composition: nuclear envelope surrounding the nucleoplasm, chromosome and nucleoli
  • Function: cellular respiration and control of photosynthesis
• Cells - smallest living unit, most are microscopic
• Principles of Cell Theory

  • All living things are made of cells
  • Smallest living unit is the cell
  • All cells arise from preexisting cells (this principle discarded the idea of spontaneous generation)
• Prokaryotic cells

  • 1st cell type on Earth
  • Cell type of bacteria and archaea
  • No membrane bound nucleus
  • Nucleoid = region of DNA concentration
  • Organelles not bound by membranes
• Eukaryotic cells

  • Nucleus bound by membrane
  • Include fungi, protists, plants, animal cell
  • Possess many organelles
• Cytoplasm

  • Viscous fluid containing organelles
  • Components: Interconnected filaments & fibers, Fluid = cytosol, Organelles (not nucleus), Storage of substances
• Nucleus

  • Control center of cell
  • Double membrane
  • Contains chromosomes and nucleolus
• DNA


  • Hereditary material
  • Chromosomes: DNA, proteins, form of cell division
  • Chromatin