Microscopy

• One microscope that is commonly used in schools is the compound light microscope.
• The compound microscope uses light and lenses to magnify objects up to about 1500 times larger than their original size.
• A light microscope using more than one lens to enlarge the object is called a compound microscope.
• A compound microscope can enlarge an object in focus with the objective lens and can be further magnified with another lens, called ocular lens or eyepiece.
• The compound microscope uses sunlight or artificial to help biologists examine cells and sections of tissue.
• The compound microscope can also be used to examine both living and nonliving specimens.
• A micrograph is a photographic image taken under a microscope.
• A stereomicroscope also known as a dissecting microscope, is used to look at the extrernal structures of a specimen such as an insect.
• The phase-contrast microscope is used to examine highly transparent objects, such as unstained cells.
• Differential interference contrast microscopy uses an optical technique to produce impressive three-dimensional images of live unstained specimens.
• An electron microscope uses beams of electrons to enlarge objects.
• There are two types of electron microscopes: transmission electron microscopes (TEM) and scanning electron microscopes (SEM)
• The transmission electron microscope is used to study internal structures of cells through sectioned specimens.
• The resolution of the TEM is up to 1000 times better than a compound microscope and up to 500,000 times better than the naked eye.
• The scanning electron microscope is used to examine the surfaces or shapes of specimens such as viruses.
• Under the SEM, a beam of electrons scan the surface of the specimen, producing a 3D image of the external structure of the specimen.
• The light fluorescent microscope illuminates objects stained with fluorescent dyes (colors that will glow in the dark).
• Fluorescence microscopy has been used extensively to study and locate certain organelles or substances inside the cell.
• The confocal scanning microscope is used to examine the 3D structure of cells or organelle without cutting the specimen into sections.
• Because of technological advancements in image processing, obects examined under the microscope can be photographed or viewed on televisions or computer screens. This process is called video microscopy.
• Cell culture is achieved with the use of a medium containing all of the food requirements for a cell to survive, grow, and multiply.
• The use of cell and tissue culture is important in the production of monoclonal antibodies called hybridoma technology, studies on the effect of drugs and toxins.