Have you ever wondered what are living organisms made of? Anything living, whether plants, animals, or microorganisms, is made of cells. These are considered the units of life, carrying out all the functions and activities occurring within the organism. Most organisms are made of millions, billions, or trillions of cells that can only be seen with a microscope. While, some organisms are composed of a single cell, generally larger than can be seen without a microscope. The microscope is an important discovery of science as it lets scientists see and explore everything invisible to their naked eye.
So, now if you are thinking about what type of cells can be seen without using a microscope, you are in the right place. Let’s explore which cells can be seen without a microscope, which cells can be seen with a microscope, and much more about cell sizes and microscopes.
Table of Contents
What is a Microscope?
A microscope is a laboratory instrument that allows one to observe and examine objects that are invisible to the naked eye. It magnifies the image of the object. A magnifying glass is considered a simple microscope as both of them are used for the same purpose. A microscope has a range of lenses, allowing one to view the image with greater resolution. The two main features of any microscope are magnification and resolution. Magnification specifies how large an object can appear and resolution specifies the smallest distance between two points from where they are considered as separate objects. Different types of microscopes have different ranges of magnification and resolution.
What is the Size of Usual Cells?
Cells usually have a size range of 1µm to 100µm. Cells, when grouped in the form of clusters can be seen by the naked eye without the aid of a microscope. However, most cells are smaller than 100 micrometers and cannot be seen without a microscope. Plant cells are generally larger than animal cells but they are still invisible to the naked eye.
What are Cells You Can See Without a Microscope?
The cells which can be seen without a microscope include large-sized amoebas and bacteria, human eggs, and paramecium. The smallest object that can be seen with the naked eye is 0.1mm long, nothing smaller than that can be detected by the unaided eye.
Amoebas are single-celled organisms, commonly found in water. Often, they cause diseases in humans. Some types of amoeba are extremely large, e.g., xenophyophores, 4 inches long, and are considered the largest amoeba to ever exist. Usually, amoebas have an average size of 0.7mm. So, some larger members of the amoeba family can be seen without a microscope.
Bacteria is usually so small that it cannot be seen without a microscope. The smallest bacteria to ever exist was 0.0002 millimeters in width. However, some types of bacteria are larger, for example, Thiomargarita namibiensis has a diameter of 750 µm. This size of bacteria can be seen without using a microscope. There are several bacteria found in the human body, some cause diseases in humans while others play important functions in the body.
Paramecium are unicellular eukaryotes found mostly in ponds and freshwaters. They have size ranges between 50-300 μ. Their large size allows them to be seen without a microscope; however, you can view the details of these unicellular organisms under some best microscopes. Paramecium has an oblong or slipper shape and has several hair-like structures around them called cilia.
The human egg cell is considered to be the largest cell of the body with a size of 100 microns. They are as wide as a strand of hair. Such a size of a cell can be seen without a microscope. No other cell of the human body can be seen with the naked eye.
What Type of Cells Can Only Be Seen with a Microscope?
Any cell that is smaller than 100 µm or 0.1mm can only be seen with a microscope. Different microscopes have different ranges of sizes they allow to be seen. Blood cells are an example of cells that are only seen with the help of a microscope. All cells of the human body except for the egg cell need a microscope to be seen and observed. Plant cells and animal cells are also seen with a microscope.
Which Microscopes Are Used to See Cells?
There are different types of microscopes with different ranges of magnification and resolution. Which microscope is suitable to use depends on which cell or organism you are about to observe. Different types of microscopes used to see cells are:
Light microscopes, specifically the binocular microscopes, were the first type of microscopes and their magnification power is 10x to 100x. Objects with 0.2 micrometers can be seen with a light microscope. Some cells and large bacteria are seen with this type of microscope.
This type of microscope has two lenses and has higher magnification power than a light microscope. The magnification power of the best compound microscopes is 40x-1000x. It allows objects to be seen which are otherwise invisible to the naked eye.
Electron microscopes are of two types, including scanning electron microscope (SEM) and transmission electron microscope (TEM). TEM magnifies an object to over 50 million times its original size. While SEM magnifies an object 1-2 million times its original size. Cellular organelles can be seen with an electron microscope.
What are the Components of Cells Visible by a Microscope?
When you observe a cell under a microscope, you will be able to see all the structures found inside and outside the cell. An electron microscope allows us to see the components of cells such as the cell wall, cell membrane, cytoplasm, nucleus, ribosomes, mitochondria, etc. By observing the components of the cell with a microscope, scientists can learn more about the functioning of different cells.
Cells are tiny building blocks of all life forms. Most of these cells lie in the range of 1-100 µm and cannot be seen with the naked eye. However, there are some organisms with single cells of large sizes that are seen without a microscope. A microscope is an instrument that enlarges the image of an object. Some large-sized cells such as those of large amoebas, large bacteria, paramecium, and human egg cells can be seen without a microscope. The human eye can see objects lying in the range of up to 0.1 mm, anything smaller than that will not be detected by the human eye. For objects smaller than this, you need a microscope. Microscopes have different magnification and resolution powers.
Frequently Asked Questions (FAQs)
Read below to find out the answers to some frequently asked questions about microscopes:
Is it possible to see a nerve cell without a microscope?
No, it is not possible to see a nerve cell without a microscope. A nerve cell is extremely small and has complex structures that can only be observed by using a microscope.
Is human DNA visible to the naked eye?
A single strand of DNA is invisible to the naked eye. However, DNA collected from thousands of cells can be seen with the naked eye.
Are skin cells visible without a microscope?
Individual skin cells are not visible without a microscope. You can see the tissues they make, but individual skin cell is so small that you cannot see them with the naked eye.
What is the smallest cell that can be seen without a microscope?
Paramecium is the smallest microorganism consisting of only one cell that can be seen without a microscope.