CELL STRUCTURE

• Who first observed cell walls in dead oak bark cells?

  Robert Hooke
• What term did Antoni van Leeuwenhoek use to describe living cells?

  Animalcules
• What were the first microscopes primarily used for?

  Improving magnification, resolution, and contrast
• What is the maximum magnification for light microscopes?

  1,000x
• What does resolution refer to in microscopy?

  Clarity of image
• What is the resolution limit of light microscopes?

  ~200 nm
• How can contrast in microscopy be improved?

  By staining or labeling
• What are the types of light microscopy?

  • Brightfield
  • Phase-contrast
  • Differential Interference Contrast (Nomarski)
  • Fluorescence
  • Confocal & Deconvolution Microscopy
• What are the types of electron microscopy?

  • Scanning Electron Microscope (SEM)
  • Transmission Electron Microscope (TEM)
• What is the purpose of cell fractionation?

  To study cellular structure and function
• What is the first step in the cell fractionation process?

  Cells are homogenized
• What does differential centrifugation achieve?

  Separates components by size and density
• What types of pellets are obtained from cell fractionation?

  Nuclei, mitochondria, microsomes, ribosomes
• How does identifying enzymes in fractions help in cell biology?

  Links structure to function
• What are the two main types of cells?

  Prokaryotic and Eukaryotic
• What is a characteristic of prokaryotic cells?

  Lack nucleus, DNA in nucleoid region
• What is a characteristic of eukaryotic cells?

  DNA in a membrane-bound nucleus
• What is the size range of prokaryotic cells?

  1-5 μm
• What is the size range of eukaryotic cells?

  10-100 μm
• What are the key structures of eukaryotic cells?

  • Plasma Membrane
  • Cytoplasm
  • Nucleus
• What is the function of the plasma membrane?

  Selective barrier for substances
• What is contained within the cytoplasm?

  Organelles and metabolic reactions
• What is the role of the nucleus?

  Stores genetic information
• What encloses the nucleus?

  Double membrane nuclear envelope
• What is the function of the nucleolus?

  Site of ribosomal RNA synthesis
• Who first observed cell walls in dead oak bark cells?

  Robert Hooke
• Who first visualized living cells ("animalcules")?

  Antoni van Leeuwenhoek
• What is the maximum magnification of a light microscope?

  1,000x
• How does a phase-contrast microscope work?

  It amplifies density variations to improve contrast
• How does a differential interference contrast (Nomarski) microscope work?

  It produces a 3D appearance of the sample
• Which type of microscope would you use to study the detailed 3D surface structure of a cell?

  Scanning electron microscope (SEM)
• Which type of microscope would you use to study the internal structure of a cell?

  Transmission electron microscope (TEM)
• What is the purpose of cell fractionation?

  To study cellular structure and function by isolating organelles
• How does the process of cell fractionation work?

  1. Cells are homogenized to break them up
  2. Differential centrifugation separates components by size and density
  3. Pellets of organelles like nuclei, mitochondria, and ribosomes are obtained
• What are the two main types of cells?

  Prokaryotic and eukaryotic
• What is the key difference between prokaryotic and eukaryotic cells?

  Eukaryotic cells have a membrane-bound nucleus, while prokaryotic cells do not
• What is the typical size range of prokaryotic cells?

  1-5 μm
• What is the typical size range of eukaryotic cells?

  10-100 μm
• What is the main function of the plasma membrane?

  It is a selective barrier that regulates the entry and exit of substances
• What is the main function of the nucleus?

  It stores the cell's genetic information and regulates gene expression