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Cells are the foundation of any living organism. Cells are the smallest units of life capable of metabolizing and reproducing. There are organisms made up of a cell capable of "eating" and reproducing and others, like us, made up of a large number of cells of different types and sizes. So the bacteria are single-celled and a multi-celled plant.
The study of cells is called cell biology or cytology. By the way, the size of the cells can be from 0.01 millimeters to 0.03 millimeters. In the animal kingdom the largest cell is the ovule, but there are unicellular algae that, although they look like an alga composed of leaves, is a single cell that can measure up to 3 meters.
In the human body we have about 30 million million cells. The number of cells in plants and animals varies from one species to another. The average size of a cell is 10 microns and it weighs almost 1 nanogram. A typical animal cell is around 10-20 microns in diameter, which is about one-fifth the size of what human eyes can see. It was not possible to see cells until we had access to a good light microscope. Another fact is that the cell is not only small, but translucent and colorless, although they may have some pigments such as chlorophyll in plants.
The cells were discovered in 1665 by Robert Hooke, who named them because of their resemblance to the cells inhabited by Christian monks in the monastery or because of their honeycomb-like appearance, since he observed the cork and there really only remained the cell walls. The cell theory was described in 1837 by the Czech scientist Jan Evangelista Purkynê, based on his experience in the microscopic examination of plant tissues.
Scientific evidence suggests that cells emerged from Earth at least 3.5 billion years ago.
Now, let's talk about the type of cells, it has two types, eukaryotes, which contain a nucleus, and prokaryotes, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be single-celled or multicellular.
We are here because we want to know how cells look under a microscope. We know that cells are tiny, but we will need something to see them, a microscope.
To know how to see a cell under the microscope, we need to know how to use a microscope! That is simple, something like that, we identify the stage, which is where we can place the glass slide with our sample, then we must select the objective we want to use, if we want a panoramic view we can choose a 5X and when we find something that we are interested in it, we will approach it by changing the objective. Once we get close to the eyepiece, the fun begins. To focus our sample, we must turn the coarse screw forwards or backwards (if we are still too far away) or the micrometric screw (for greater precision). Do it very carefully, if you are too close you can break the slide.
To see an object, we must calculate the magnification, the eyepiece lens and the objective lens magnification are multiplied to get the total magnification, so the equation is: total magnification = magnification of the eyepiece lens x magnification of the objective eye. For example: 10 x 20 = 200, based on this, our increase will be 200.
Now a specific example to see bacteria under the microscope. Bacteria are prokaryotic cells, that is, they are unicellular without a nucleus, while they are very small, they vary in shape and size. There is a method that is used to distinguish and classify bacterial species into two groups: gram-positive bacteria and gram-negative bacteria.
The names come from a Danish bacteriologist Hans Christian Gram (1853-1938), who developed the technique. These groups of bacteria are based on their different components of the cell wall. This procedure distinguishes between groups by coloring these cells red or purple. Violet staining is positive due to the presence of a thick layer of peptidoglycan on its cell walls. On the other hand, Gram negative bacteria stain red, which is attributed to a thinner peptidoglycan wall.
Since they are transparent, their color will show only if they are present in a colony. It takes a lot of experience to differentiate bacteria from dust or dirt that is present on the slide.
This identification is very important because gram positive bacteria cause infections, for example pneumonia and gastroenteritis.
What did you think of the world of cells? Did you know that bacteria can be shaped like cocci or sticks called bacilli?
We say goodbye saying that in the digestive tract (if you eat well) they have a large number of bacteria that work in harmony with your body to keep you healthy, they are known as microbiota where there are more than 100 million microorganisms that weigh about 200 grams. Approximately the weight of an apple!
We recommend you see gram positive and negative bacteria
GRAM POSITIVE VS GRAM NEGATIVE BACTERIA
So that you know more about the microbiota
How Bacteria Rule Over Your Body – The Microbiome