Bioo

• Cell Biology


  A branch of biology that studies the different structures and functions of the cell
• Aspects of cell biology

  • Structure
  • Organelles
  • Physiological Properties
  • Metabolic Processes
  • Signaling Pathways
  • Life Cycle
  • Interactions with their Environment
• Hans and Zacharias Janssen, Dutch father-son duo, created the first compound microscope

  1600
• Microscope created by Hans and Zacharias Janssen


  • Microscopic type: Compound (bi-convex eyepiece/plano-convex objective)
  • Magnification: 3X to 9X
• Galileo Galilei built his 'occhiolino' (little eye) microscope


  1609
• Galileo Galilei's microscope

  • Microscopic type: Compound (bi-concave eyepiece/bi-convex objective)
  • Magnification: Up to 30X
• Giovanni Faber


  German doctor and botanist who named the 'microscope' from the Greek 'micron' (small) and 'skopein' (to look at)
• Robert Hooke published 'Micrographia' containing illustrations of insects and plants viewed through a microscope


  1665
• Robert Hooke's observation


  He used the word cells to describe the "boxes" he had observed in the cork (cork cells are dead plant cells)
• Anton Van Leeuwenhoek, known as the "Father of Microbiology", made microscopes by grinding his own lenses and was the first to view pond water organisms and living microscopic organisms which he called animalcules

  1675
• Robert Brown discovered the nucleus in the cell

  1833
• Matthias Schleiden discovered that plants are made up of cells

  1838
• Theodore Schwann founded modern histology by defining the cell as the basic unit of animal structure

  1839
• Jan Evangelista Purkinje

  Coined the term "protoplasm"
• Rudolf Virchow studied cell reproduction and stated "Where a cell exists, there must have been a preexisting cell" and "Omnis cellula e cellula"

  1855
• Cell Theory


  A scientific explanation that describes how living organisms are structured and includes the basic properties of cells
• Unified Cell Theory


  • All living things are composed of one or more cells
  • The cell is the basic unit of life
  • New cells arise from existing cells
• Modern Cell Theory


  • All organisms are made up of one or more cells
  • The cell is the fundamental unit of structure and function in living things
  • Cells arise from other cells through cellular division
• Expanded Cell Theory


  • Cells carry genetic material passed to daughter cells during cellular division
  • All cells are essentially the same in chemical composition
  • Energy flow (metabolism and biochemistry) occurs within cells
• Prokaryotic cell


  Single-celled microorganisms known to be the earliest on earth, including Bacteria and Archaea
• Characteristics of prokaryotic cells


  • Lack a nuclear membrane
  • Lack mitochondria, Golgi bodies, chloroplast, and lysosomes
  • Genetic material is present on a single chromosome
  • Lack histone proteins
  • Cell wall is made up of carbohydrates and amino acids
  • Plasma membrane acts as the mitochondrial membrane
  • Divide asexually by binary fission, sexual reproduction involves conjugation
• Examples of prokaryotic cells

  • Bacterial cells
  • Archaeal cells
• Eukaryotic cell


  Cells that contain membrane-bound structures or organelles and are the basis of every multicellular organism
• Types of eukaryotic cells

  • Plant cells
  • Animal cells
• Eukaryotic cells are cells containing membrane-bound organelles and are the basis for both unicellular and multicellular organisms
• Prokaryotic cells do not have any membrane-bound organelles and are always part of unicellular organisms
• Both prokaryotic and eukaryotic cells have similar features, like ribosomes, genetic material, a cytoplasm, and plasma membranes
• Difference between prokaryotic and eukaryotic cells

  • Nucleus and other membrane-bound organelles are only present in eukaryotic cells
  • Prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms
  • Eukaryotic cells are more than 100 to 10,000 times larger than prokaryotic cells and are much more complex
  • The DNA of eukaryotic cells has proportionally less coding DNA and high amount of non-coding DNA compared to prokaryotic cells
• All prokaryotic and eukaryotic cells have some similar features as they both contain ribosomes, genetic material, a cytoplasm, and plasma membranes
• Bacteria


  Small single-celled organisms found almost everywhere on Earth, some are harmless and some are helpful (resident bacteria) while others are pathogenic
• Shapes of bacteria

  • Spheres (cocci bacteria)
  • Rod-shaped (bacilli)
  • Helixes (spirochetes)
• Types of bacteria based on need for oxygen

  • Aerobes (need oxygen)
  • Anaerobes (can't live with oxygen)
  • Facultative (can live with or without oxygen)
• Types of bacteria based on staining

  • Gram-positive (look blue to purple under gram stain)
  • Gram-negative (look red to pink under gram stain)

  
• Examples of bacterial diseases

  • Tuberculosis
  • Pneumonia
  • Urinary tract infections (UTI)
• Virus

  Infectious microbe that consists of a segment of nucleic acid (either DNA or RNA) and must infect a cell and take over the cell's metabolic machinery
• Viruses are much smaller and simpler in structure compared to cells, and are capable of causing many diseases but cannot carry out metabolism outside of a host cell
• Viruses consist of a nucleic acid surrounded by a protein coat and are obligate intracellular parasites that replicate only within host cells

  
• The discovery of viruses is credited to German scientist Adolf Mayer, Russian biologist Dimitri Ivanowsky, and Dutch botanist Martinus Beijerinck

  
• Parts of a virus

  • Capsid
  • Viral envelopes
  • Virus genomes made of DNA or RNA

  
• Examples of viruses

  • Adenoviruses
  • Bacteriophages