BIOLOGY CELL

• Why is the use of the mouse important in biomedical research?

  It is of major importance for experimentation
• What is the study of cell structure called?

  Cytology
• What does histology study?

  Microscopic study of tissue structure
• What is cell physiology concerned with?

  Study of cell function
• How does cell biology relate to cytology, histology, and physiology?

  Cell biology studies the structure and function of cells, overlapping with cytology, histology, and physiology
• Why is cell biology more dependent on new instruments and technologies?

  Because the subject matter of cell biology is small
• What is essential to learn about cell biology?

  Understanding the technology required to collect data
• What general methods and apparatus are used in cell biology?

  • Visualization of cellular structures
  • Isolation of cellular components
  • Characterization of cellular functions
• What does magnification refer to in microscopy?

  Increase in size via objective and eyepiece lenses
• What does resolution in microscopy depend on?

  Quality and sharpness, which depends on diffraction
• How does visibility in microscopy improve?

  By using dyes (stains) that bind to different biological molecules
• What type of microscopy is bright-field microscopy suited for?

  High contrast specimens such as stained samples
• What are whole mounts in microscopy?

  Intact specimens, living or dead, suitable for stereo microscopy
• What are the types of microscopes mentioned?

  • Compound microscope
  • Inverted microscope
• What does Feulgen staining visualize?

  Chromosomal DNA during metaphase

  
• What is the purpose of phase-contrast microscopy?

  To make transparent objects more visible without staining
• What causes halos and shading in phase-contrast microscopy?

  Sharp changes in refractive index at edges
• What is differential interference contrast (DIC) microscopy?

  A more advanced phase contrast system that creates an almost 3D image
• How does fluorescence microscopy work?

  It uses fluorochromes that absorb UV radiation and emit visible light
• What is an example of a stain used for DNA visualization?

  Feulgen stain
• What is the process of preparing sections for microscopy?

  Cells or tissues are fixed, embedded in paraffin, sectioned, and stained

  
• What is a disadvantage of sectioning specimens?

  It kills living organisms, preventing the study of dynamics
• What are examples of fluorochromes?

  Rhodamine, fluorescein, acridine orange, GFP, BFP, YFP, CFP
• What does FRET measure?

  Nanoscale distances between fluorochromes
• How does confocal microscopy improve image quality?

  By focusing a laser beam at a single depth to illuminate a thin plane

  
• What is the role of the pinhole aperture in confocal microscopy?

  It allows only light from the focused plane to enter

  
• What is the advantage of laser scanning confocal microscopy?

  It can reconstruct sharp 3D images from multiple planes
• What is the main advantage of transmission electron microscopy (TEM)?

  It provides much higher resolution using electrons instead of light
• How are electron beams focused in TEM?

  By electromagnetic lenses in a vacuum column
• What is the range of magnification in TEM?

  1000 to 250,000 times
• Why do specimens need to be fixed and stained with heavy metals in TEM?

  Because cell constituents have a low atomic number, requiring better contrast
• What are the techniques for specimen preparation for TEM?

  • Cryofixation
  • Negative staining
  • Shadow casting

  
• What is cryofixation?

  Ultrarapid freezing of specimens using liquid propane or helium
• What is the purpose of negative staining?

  To visualize very small particulate material like viruses and ribosomes
• How does shadow casting work?

  Metal is deposited on surfaces facing a heated filament, creating shadows
• What does freeze fracture reveal?

  Fracture face elevations, depressions, and ridges reflecting organelle contours
• Why is freeze fracture suitable for examining integral membrane proteins?

  Because it splits through membranes, revealing protein structures
• What is the purpose of critical-point drying in SEM?

  To preserve structures without exposing cells to surface tension
• How does SEM form an image?

  By detecting backscattered electrons from the metal cast
• What is the range of magnification in SEM?

  15 to 150,000 times