2.1: Parts of the Microscope - Biology

2.1: Parts of the Microscope - Biology

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Become familiar with the location and function of the following parts.

  1. Arm and Base
  2. Ocular lens – magnifies by 10X
  3. Revolving nosepiece – contains 3 objective lenses
    1. scanning objective lens magnifies by 4X
    2. low power objective lens magnifies by 10X
    3. high power objective lens magnifies by 40X
  4. Stage and stage clips – hold the slide for viewing
  5. Stage adjustment knobs – located below the stage to control forward/reverse and side to side movement of the stage
  6. Coarse adjustment knob – for focusing ONLY when using scanning objective lens
  7. Fine adjustment knob –brings object into clearest focus
  8. Iris diaphragm – controls the amount of illumination to improve contrast and resolution

2.1: Cell Theory (the first part)

The discovery of the cell was made possible by the invention of the microscope, which was made possible by improved lens-grinding techniques. Antoni van Leeuwenhoek (1632-1723), a Dutch tradesman, learned to grind lenses and assemble them into simple microscopes. His contemporary Robert Hooke (1635-1703) used such an instrument to observe cork cells, sketches of which appeared in his 1665 publication “Micrographia.” Inspired by Hooke’s work, Leeuwenhoek began making microscopic examinations of his own. In 1678, he reported to the Royal Society that he had discovered “little animals” — bacteria and protozoa — in various samples. The society asked Hooke to confirm Leeuwenhoek’s findings, and he did.

Aaron Bell/Visuals Unlimited/Getty Images

In 1678, Antoni van Leeuwenhook reported that he had observed “little animals” — protozoa — through a microscope.­

T­his paved the way for wide acceptance that a hidden world existed just beyond the limits of human vision and encouraged many scientists to take up the microscope in their investigations. One such scientist was German botanist Matthias Jakob Schleiden (1804-1881), who looked at numerous plant samples. Schleiden was the first to recognize that all plants, and all the different parts of plants, are composed of cells. While having dinner with zoologist Theodor Schwann (1810-1882), Schleiden mentioned his idea. Schwann, who came to similar conclusions while studying animal tissues, quickly saw the implications of their work. In 1839, he published “Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals,” which included the first statement of the cell theory: All living things are made up of cells.

Then, in 1858, Rudolf Virchow (1821-1902) extended the work of Schleiden and Schwann by proposing that all living cells must rise from pre-existing cells. This was a radical idea at the time because most people, scientists included, believed that nonliving matter could spontaneously generate living tissue. The inexplicable appearance of maggots on a piece of meat was often given as evidence to support the concept of spontaneous generation. But a famous scientist by the name of Louis Pasteur (1822-1895) set out to disprove spontaneous generation with a now-classic experiment that both firmly established the cell theory beyond doubt and solidified the basic steps of the modern scientific method.

An Animation from TedEd explaining The Cell Theory – The link in the animation takes you to the TedEd lesson to accompany this, which included a quick MCQ to check what you understand.

The amazing scale of the universe animation lets you examine cells in comparison to the rest of the universe

The Basic Components Of A Microscope

Three microscope parts make up the frame of the device.

The base is the large piece that supports the microscope. You need to keep your microscope steady to get a clear image of what you want to magnify. This is why the base is an important part.

The size of the base depends on how heavy the microscope is. If you need to carry a microscope, make sure you place one hand under the base to support the weight of the device.

This is the C-shaped section that connects the base of the microscope to the controls and tube. You can typically adjust the angle of the arm to use the microscope more comfortably.

The arm is the first part that young students should learn about. This is the part you would use to safely pick up and transport the microscope. Teach students that they should always grab the arm of the microscope if they need to change the position of the device.

When carrying a microscope, you should hold the device by the arm and have one hand under the base to support its weight.

If you are using a compound microscope, the base, arm, and stage of the device won’t be separate elements. However, these different parts are easily identifiable on most small microscopes with low magnification settings.

This is a large part at the top of the microscope. The tube is connected to the arm of the microscope.

You will find the turret or nosepiece with the magnifying lenses at the bottom of the tube. However, you don’t directly look down the tube since an eyepiece is mounted on top of the tube.

The tube of a microscope can’t be adjusted. Make sure you teach the name of this part to young students, so they know not to grab a microscope by its tube.

Some microscopes have two tubes and two eyepieces. Most models only have one tube and eyepiece.

It can be explained as follows the ultrafast electron pulses with a duration of couple hundreds of femtosecond are generated by the photoemission process by.

Thus, we will use the activation of mCherry’s expression as an indicator of the interactions between the bacteria within microstructures and the environment .

This X-ray spectrum consists of several components. These X-rays are then collimated to get Kα1 and Kα2 radiations then directed towards the sample. When Bra.

Scheme 5 illustrates the components of our custom-built bioanalytical sensor. A 532 nm solid-state laser is used as the excitation source to closely match th.

Each well is loaded with products from a different reaction. The strand being sequenced will have the opposite Watson-Crick base, meaning the well loaded wit.

A stage micrometer is essentially a ruler that is mounted to the microscope slide that does have units (millimeter or micrometer). When calibrating, the stag.

Is finding out the total the total magnification, which is done through multiplication of the number on the eyepiece and the objective magnification. Discuss.

Staining techniques allow for microorganism size, shape, motility and proximate arrangement to be assessed. These characteristics are important in identifyin.

This practical consisted of five parts which each focussed on different functions of microscopes and processes involved in viewing specimens under a light mi.

In this lab, the main purpose of this experiment is to identify the biochemical characteristics of an unknown bacteria by using first the Gram Stain and base.

Quiz over the Parts of the Microscope

If you would like to use this quiz in your own class and view student scores, go this FORM and “make a copy” for your own drive.

You can also click on this link and it will automatically create a copy in your own drive.



can you share this form with me? i need one just like this now that i am teaching from home due to covid19. do you sell this material or can you just share for class use?


For forms and other documents, you would need to open the document and “make a copy” for your own drive. That way you can edit it and see results. If you just share the one I posted, I’m the only one that can see the results. Google forms does not make the process easy.

Chelsie Inabnitt

I do not see the option for me to make a copy of this. This looks like an awesome resource!

Final Thought

The microscope is one of the instruments which is available in all of the science labs. It is used to view the small microorganisms or other objects not visible with the naked eyes. You need learn about microscope parts and functions to help accomplish different scientific tasks. This device is not difficult to use but requires the knowledge of different parts before using it. The entire details about the parts and their functions are provided in this article and you can gather the required information.

The Flowers

The flowers are the reproductive parts of plants. The flowers often have brightly colored petals to attract pollinators. In the center of a flower, there are female parts called pistils and male parts called the stamen. In this slide of lily flower, you can see the pollen grains inside the pollen sac of the anther (the structure at the tip of stamen). Mature pollen grains will be released and carried by wind or insects to pistils.

[In this figure] The anatomy of lily flowers.
The lily flowers contain a pistil, several stamens, and petals. The cross-section of a lily anther shows the pollen sac containing many pollen grains inside. Pollen grains are very beautiful and delicate viewing by a higher magnification.


As already mentioned, giardiasis is an infection of the small intestine caused by Giardia lamblia.

While the parasite invades the small intestine (particularly duodenum), studies have shown that it does not penetrate cells of the small intestine. Moreover, it does not invade the epithelium nor venture into the bloodstream.

With regards to the mechanism through which Giardia causes giardiasis, a combination of malabsorption and hypersecretion have been shown to be the primary causes of diarrhea.

By attaching to the cells of the epithelial wall/mucosa ( enterocytes) , Giardia was shown to cause shorting or the microvilli and thus lose epithelial wall function (absorptive function of the epithelial surface). As a result, the epithelial surface is incapable of properly absorbing such nutrients as glucose as well as water and other nutrients.

Apart from malabsoption, giardia infection was also associated with hypersecretion of chloride, which has been shown to contribute to fluid accumulation in the lumen of the intestine.

* Giardia species have been shown to share a number of metabolic and genetic characteristics with bacteria thus contributing to their unique characteristics that distinguish them from other eukaryotes.

Giardia has been shown to contain bacterial glycolytic enzymes that allow them to obtain energy through fermentation (by relying on pyrophosphate).

Parts and functions of a compound microscope

(A) Arm

Used to carry the microscope.

(B) Base

Supports the microscope and houses the light source.

(C) Oculars (or eyepieces)

The lens of the microscope you look through. The ocular also magnifies the image. The total magnification can be calculated by multiplying the objective power by the ocular power. Oculars come in different magnifications, but 10× magnification is common.

(D) Diopter adjustment

The purpose of the diopter adjustment is to correct the differences in a vision an individual may have between their left and right eyes.

(E) Interpupillary adjustment

This allows the oculars to move closer or further away from one another to match the width of an individual’s eyes. When looking through the microscope, one should see only a single field of view. When viewing a sample, always use both eyes. Using one eye can cause eye strain over a period of time.

(F) Nosepiece

The nosepiece holds the objective lenses. The objectives are mounted on a rotating turret so they can be moved into place as needed. Most nosepieces can hold up to five objectives.

(G) Objective lenses

The objective lens is the lens closest to the object being viewed, and its function is to magnify it. Objective lenses are available in many powers, but 4×, 10×, 40×, and 100× are standard. 4× objective is used mainly for scanning. 10× objective is considered “low power,” 40× is “high power” and 100× objective is referred to as “oil immersion.” Once magnified by the objective lens, the image is viewed through the oculars, which magnifies it further. Total magnification can be calculated by multiplying the objective power by the ocular lens power.

For example 100× objective lens with 10× oculars = 1000× total magnification.

(H) Stage

The platform on which the slide or object is placed for viewing.

Figure 798.1: Compound microscope

(I) Stage brackets

Spring-loaded brackets, or clips, hold the slide or specimen in place on the stage .

(J) Stage control knobs

Located just below the stage are the stage control knobs. These knobs move the slide or specimen either horizontally (x-axis) or vertically (y-axis) when it is being viewed.

(K) Condenser

The condenser is located under the stage. As light travels from the illuminator, it passes through the condenser, where it is focused and directed at the specimen.

(L) Condenser control knob

Allows the condenser to be raised or lowered.

(M) Condenser centering screws:

These crews center the condenser, and therefore the beam of light. Generally, they do not need much adjustment unless the microscope is moved or transported frequently.

(N) Iris diaphragm

This structure controls the amount of light that reaches the specimen. Opening and closing the iris diaphragm adjusts the diameter of the light beam.

(O) Coarse and fine focus adjustment knobs

These knobs bring the object into focus by raising and lowering the stage. Care should be taken when adjusting the stage height. When a higher power objective is in place (100× objective for example), there is a risk of raising the stage and slide and hitting the objective lens. This can break the slide and scratch the lens surface. Coarse adjustment is used for finding focus under low power and adjusting the stage height. Fine adjustment is used for more delicate, high-power adjustments that would require fine-tuning.

(P) Illuminator

The illuminator is the light source for the microscope, usually situated in the base . The brightness of the light from the illuminator can be adjusted to suit your preference and the object you are viewing.

Watch the video: Microscopes and How to Use a Light Microscope (January 2023).