microscopes

• transmission electron microscopes use electrons to form an image of a specimen
• the resolution of a transmission electron microscope is around 0.2nm
• a scanning tunnelling microscope uses a sharp metal tip that moves across the surface of a sample, detecting changes in electrical current as it goes.
• a light microscope is used to observe living organisms and their structures.
• types of light microscopes include: fluorescence microscopy, light microscopy and confocal microscopy
• fluorescence microscopy involves shining ultraviolet light onto a specimen containing fluorochromes which absorb UV light and emit visible light at longer wavelengths
• confocal microscopy produces images by focusing on one plane only, allowing multiple layers to be seen without interference from other planes
• a compound light microscope has an objective lense that provides the main magnification, which is compounded by the eye piece lense. The. light then passes through the specimen to provide an image.
• scale bar: FOV divided by circumference of drawing is how many um to one cm
• label the cell

  A) nucleus

  B) Nucleolus

  C) nuclear membranee

  D) smooth endoplasmic reticulum

  E) mitochondria

  F) centriole

  G) micro tubules

  H) ribosome

  I) cytosol

  J) rough endoplasmic reticulum

  K) golgi apparatus

  
• label the microscope

  A) stage

  B) light source

  C) diaphragm

  D) stage adjustment knobs

  E) ocular lenses

  F) rotating nose piece

  G) objective lense

  H) course focus knob

  I) fine focus adjustment

  J) mechanical stage

  
• 1mm = 1000micrometre
• 1 micrometre = 1000 nanometres
• light microscopes can create coloured images
• state of cell of specimen

  light microscopes can view living cells or organisms. Elelctron microscopes can only view dead or non-living cells or organisms.
• light microscopes have a lower resolution and the resolution for electron microscopes are higher.
• the maximum level of magnification for a light microscope is 2000x
• the maximum level of magnification for electron microscopes is 10000000x
• light microscopes are focused by glass lenses
• electron microscopes are focused by electromagnets.
• electron microscopes have a higher resolution that light microscopes because electron microscopes have smaller wave lengths of electrons meaning that they are more likely to bump into the specimen and organelles.
• organelle light microscope can see

  chloroplasts, cell walls, plasma membrane, nucleus, vacuole
• how are microscope specimens drawn

  • the date that you viewed the specimen and drew the diagram
  • the magnification you used with the microscope (multiply the eyepiece and objective lens)
  • a scale bar showing the size of one cell.