Fast solutions for complex problems

Why do you usually need to cut a very thin slice of specimen to look at it under a light microscope?

Because beams of electrons can only pass through thin samples, cells and tissues must be cut first into ultra thin slices before they can be examined under a transmission electron microscope.

Why do sections of specimens have to be thin?

For TEM, samples must be cut into very thin cross-sections. This is to allow electrons to pass right through the sample. After being fixed and dehydrated, samples are embedded in hard resin to make them easier to cut.

Why is it necessary to use thin samples of tissue when viewing cells using a light microscope?

Scientists use stains to colour their samples of biological tissue before viewing them through light microscopes. Stains highlight particular components of the sample and make it easier to interpret. Some stains require the sample to be treated beforehand, and in this case, the tissue is no longer living.

What is the importance of viewing specimen under the microscope?

Microscopes are used in viewing the specimens that are relatively very small in size, they are used to view the cellular structures of organs, germs, and bacteria, They play a very important role in the laboratory for the tissues and organisms which are too small to be seen clearly with the naked eye.

What can be viewed under a light microscope?

You can see most bacteria and some organelles like mitochondria plus the human egg. You can not see the very smallest bacteria, viruses, macromolecules, ribosomes, proteins, and of course atoms.

What Cannot be viewed with a compound light microscope?

What controls the amount of light passing through a slide on the microscope stage? Viruses can/cannot be viewed with compound light microscope.

How are specimens prepared for a light microscope?

There are two basic types of preparation used to view specimens with a light microscope: wet mounts and fixed specimens. The simplest type of preparation is the wet mount, in which the specimen is placed on the slide in a drop of liquid. The second method of preparing specimens for light microscopy is fixation.

Which objective is used when you start to focus a specimen?

When focusing on a slide, ALWAYS start with either the 4X or 10X objective. Once you have the object in focus, then switch to the next higher power objective.

What can be seen with a light microscope?

What are the advantages and disadvantages of light microscope?

Advantage: Light microscopes have high magnification. Electron microscopes are helpful in viewing surface details of a specimen. Disadvantage: Light microscopes can be used only in the presence of light and have lower resolution. Electron microscopes can be used only for viewing ultra-thin specimens.

What are the disadvantages of microscope?

The main disadvantages are cost, size, maintenance, researcher training and image artifacts resulting from specimen preparation. This type of microscope is a large, cumbersome, expensive piece of equipment, extremely sensitive to vibration and external magnetic fields.

How do you view a specimen under a microscope?

How to use a microscope

  1. Move the stage (the flat ledge the slide sits on) down to its lowest position.
  2. Place the glass slide onto the stage.
  3. Select the lowest power objective lens.
  4. Turn the coarse focus knob slowly until you are able to see the cells.

When do you need to prepare a sample for a microscope?

For many types of microscopes, especially light or bright field microscopes, some form of specimen sample preparation must be done before the specimen can be viewed under the microscope. Take for example a compound light microscope. It makes use of microscope slides to mount the specimen on, before loading it onto the microscope for viewing.

Why do you cut a very thin slice of specimen to look under?

Based on other people’s answers on other sites, the best answer I got was because the generated light source needs to ba able to shine through the specimen. This allows for better observations and to see individual cells. Home

Why do we need a thin sample of specimen when viewing?

If the microscope has any kind of objective (as for mainly all optical microscopes) the depth of focus is limited, thus allowing only for a limited thickness inside the sample to be imagined sharp. All layers that are out of focus contribute to the overall noise of the image thus degrading image quality.

What is called that you look at under a microscope?

The light is reflected upwards, and passes through the specimen. It passes through easier (clearer) if the specimen is not too thick. What is the object called that you look at under a microscope?