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Microbiology

Learn the toughest concepts covered in Microbiology with step-by-step video tutorials and practice problems by world-class tutors.

7. Prokaryotic Cell Structures & Functions

Bacterial Cell Morphology & Arrangements

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Bacterial Cell Morphology & Arrangements

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In this video, we're going to begin our lesson on bacterial cell morphology and arrangements. And so first we need to distinguish between the two terms morphology and arrangement, which are two terms that we're going to be using a lot over the next few videos. And so cell morphology is referring to the overall shape of individual cells. And so really the term morphology is just a fancy term that means shape. Now cell arrangement is a little bit different because cell arrangement does not refer to the shape. Instead, cell arrangement refers to the organization or the alignment of groups of multiple cells. And so what we'll see moving forward is that there are three main types of morphology. Zor three main types of shapes but there are many different types of arrangements. And so we'll go through some of those as we move forward in our course. And so I'll see you all in our next video.
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Types of Bacterial Cell Morphology

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in this video we're going to begin our lesson on the types of bacterial cell morphology. And so bacterial cells typically range between 0.2 to 2.0 micro meters In diameter and about 2-8 μm in length. And so bacteria are very, very small. Now really there are three main bacterial cell morphology is that we have numbered down below one, two And three over here. And so the first bacterial cell morphology is caucus and caucus is circular shaped. And so as you can see down below, the shapes of some bacteria are circular as you can see here. And so uh staphylococcus arias is an example of a bacteria that has circular morphology, caucus morphology. Now the next one that we have here is bacillus and bacillus is a rod shaped morphology. And so you can see here that it creates these elongated rods as you see here. And an example of this is actually a shriek E. Coli which or E. Coli which creates these rod shapes or this bacillus morphology and then last but not least. The third main type of morphology that bacteria can take is spurring lem and spiral. Um is a corkscrew shape. And so what you can see it has this spiral or corkscrew shape. As you can see here in this image, An example of this is spiral um minus a specific bacteria that has this corkscrew shape or this perilla um morphology. And so you can see that we have the little corkscrew over here just to help remind you of spiral um being a corkscrew shape or this spiral shape as you see like that. And so this here concludes our brief introduction to the types of bacterial cell morphology or the types of shapes that bacteria mainly take on. And as we move forward in our course, will start to talk more about the arrangements that the bacteria take, which once again do not confuse morphology with arrangement morphology refers to the shape either caucus, bacillus or spiral, um and then arrangement refers to the organization or the alignment of multiple cells, which we'll talk about later. So I'll see you all in our next video.
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Cocci Bacterial Cell Arrangements

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in this video, we're going to focus in on cox i bacterial cell arrangements. And so cox I is the plural form of caucus, which recall from our previous lesson video is one of the three main types of bacterial cell morphology ease, and cox I is referring to a circular shaped morphology. And so the Kochs ir circular shaped bacterial cells that can be either round or spherical or flattened like a hockey puck. And so uh the cox I can have many different arrangements. And so these cocks I cells can be arranged or organized in many different ways after cell division. Now it's important once again not to confuse morphology with arrangements, recall that morphology is referring to the shape and notice that all of these cells down here all have the same cox I. Or caucus shape, which is circular. And so the shape here or the morphology is not to be confused with the arrangement. And the arrangement is how these cells are arranged or organized. And so notice that all of these are different arrangements, even though they all have the same morphology, the same shape. And so the first arrangement that we have appeared at the top left is diplo cox I. And so notice the cox I. Root here is referring to the morphology, the circular shape and the die here is a route that means to and so die bloke oxide or diplo cox I. Is referring to two cells that remain attached after cell division. And so when a cell divides, it divides into two cells as you see here, but they remain attached to create this diplo cox I formation here. And so in this area, gonorrhea is an example of a bacteria that takes on this diplo cox I arrangement. Now, the next arrangement that we have over here is streptococcus side. Once again, the cox I root here is referring to the morphology, the circular shape and the root strep toe is really important here. And so strep toe is a route that is referring to a chain. And so streptococcus I are going to have a chain like pattern of multiple cells. And so you can see that they are cox I shape, They are circular but they create this chain, this long chain of cells. And so that is what makes them strep toe have that stretched arrangement. And so notice that streptococcus by a chinese is an example of the bacteria that creates this chain like arrangement. This streptococcus arrangement. Now the next more arrangement that we have here is the te trad and the tetra tetra is a route that means four. So this is going to be a cluster of four cells that are arranged on the same plane. And so you can see these four cells are all caucus, they're all circular shaped but they are arranged in a tetrapod where there are four cells in the same plane. And so you can see that micro caucus lucius is an example of an organism that creates this tetrapod arrangement. And so you can kind of see there's a tat trad that's right here which is kind of overlapping with this other ted tried that you see here. And so you can see that the test track can kind of be somewhat off a little bit. But for the most part you can see that they can create this ted trad arrangement here. Then the next arrangement that we have here is Sarsania and Sarsania is a cluster of eight cells arranged into a cube. And so you can see here that there is this cube like arrangement. And there are eight cells that participate in this cube like arrangement. And so Sarsania ventricular to is an example of a bacteria that has this Sarsania arrangement. So then the last arrangement that we have here is staphylococcus side which once again you can see the cox I. Root here is referring to the caucus or circular shaped morphology but then it's the staff alot route which is really important here. And staff alot is not to be confused with schlep toe recall, strep toe is a chain like arrangement whereas staff alot staff alot is referring to a cluster. And so this is referring to a cluster of many cells in an irregular pattern so they don't really make a specific pattern that's recognizable. And so you can see here we have this big cluster of these circular shaped bacteria. And the cluster here is what makes this arrangement. Staff alot up And so you can see that staphylococcus arias is an example of this, a bacteria that has this particular arrangement. And so this here concludes our brief lesson on cox i bacterial cell arrangements. And we'll be able to get some practice applying this as we move forward in our course. And we'll also get to learn a lot more about different types of arrangements as well. So I'll see you all in our next video.
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Streptococcus bacteria have what shape?

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Bacilli Bacterial Cell Arrangements

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in this video we're going to focus in on the bacilli bacterial cell arrangements. And so basilica is really the plural form of bacillus, which recall from some of our previous lesson videos is one of the three main types of bacterial cell morphology is where bacteria take on a rod shape. And so bas il I recall are going to be rod shaped bacterial cells and they can only divide across their short access. They cannot divide along their long axis. And so for example if we're looking at a bacilli uh sell like what you see down here, it can only divide along its short access. So it can only divide this way. It cannot divide along the long axis so it cannot split like this. And so because but still I can only divide in one plane. They have fewer possible arrangements than the cox I which can divide in many different planes. And so let's take a look at some of these arrangements. For the basilica. First we have a single bacillus which is actually a single cell. And this is the most common arrangement for bacillus bacteria. And so you can see that here we have a single cell that has this rod shape, this bacillus morphology. And so an example of this is E coli or Escherichia coli. The next arrangement that we have over here is diplo basil I. And once again the route die is a route that means to. And so this is once again going to be when there are two cells that remain attached after division. And so once again notice that this cell divided along its short access to create two cells here. And so this is just a chain of two. And so that's why it's diploma scylla. And so an example of this is bacillus mega terry, um which you can see has a chain of two cells. And that arrangement, the next arrangement that we have is strep Tobias ally. And once again, the route strep toe uh is a route that's referring to a chain. And so this is going to be bacile I in a chain like pattern of multiple cells. And so you can see here there's a chain of multiple bacile I all linked up in a long chain here. And so that's why it is strep to priscilla. And an example of this is bacillus and the racist. So you can see uh the images here and it has all of these bacterial cells linked in a chain. Then last but not least what we have over here on the far right is kokko bacilli, which is really just a mixture of caucus and bacillus in a diplo format. And so these are going to be short rod shaped ovals, um or ovals, short rods or short ovals that can appear as diplo cox I. And so they look a lot like diplo cox I. And it's very, very difficult to tell the difference between them unless you're an expert. However, they are slightly different and they have somewhat of emerge between the caucus and the bacillus as And so an example of this is cox CLR Bernetti, who you can see. Uh It's arrangement is just going to be somewhat of a diplo, but the morphology is a mixture between caucus and bacillus. And so we refer to these as kokko bacillus. And so this year concludes our brief introduction to Vasily bacterial cell arrangements. And once again, we'll be able to get some practice and learn more about arrangements as we move forward in our course. So I'll see you all in our next video
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Problem

What is the morphology of the cells in the image below?

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Spiral-shaped Bacterial Cells

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in this video we're going to focus on spiral shaped bacterial cells. And so spiral shaped cells can actually have a few varied morphology ease or shapes that are never completely straight and so down below in this image we're showing you three different morphology ease of spiral shaped cells. The first one on the far left is vibrio, which is really a bent shaped short curved rod. And so you can see that it has this bent shape here, it's not completely straight and so it's barely a spiral but it is going to create this curve here that is the beginning of a spiral. And so vibrio cholera is an example of a bacteria that takes on this vibrio shape. And so you can see that these bacteria are curved. As you can see here in this image now, the next one that we have here is spiral um which we already talked about in some of our previous lesson videos. These are curved rods that actually form a full spiral. And you can see that this right here it resembles a corkscrew and it is forming a spiral shaped and so once again spiral a minus is an example of a bacteria that has that cork screw or spiral spiral um shape. Now the third one that we have over here is very similar to the spiral. Um But the difference is the spirit heat which is this last one here is going to be much longer than the spiraling. And not only is it much longer but it's also going to have more flexible cells And the spiral will not be as tight since it's more elongated and so you can see here it does have this curved spiral shape but it is much more elongated and it is going to be much more flexible. And so borrelia burgdorferi is an example of a bacteria that takes on the spirit heat uh morphology. And so this here concludes our brief lesson on spiral shaped bacterial cells. And once again, we'll be able to get some practice as we move forward, so I'll see you all in our next video.
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Problem

Vibrio cholerae causes the disease cholera. Based on the name of the bacterium, what is its shape?

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Which of the following is mismatched:

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Problem

A chain of rods is referred to as ______________, whereas a curve shaped rod is termed _______________.

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What type of cell is shown in the image below?

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What type of cell arrangement is shown in the image below?

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Match the following cell morphologies with the correct description:

1) ______:Diplobacilli                     A. Long spiral with flexible cells.

2) ______:Streptococci                  B. Single rod-shaped cell.

3) ______:Vibrio                             C. 2 rod-shaped cells that remain attached.

4) ______:Diplococci                     D. Cluster of 4 spherical cells arranged on one plane.

5) ______:Spirochete                    E. 2 spherical cells that remain attached.

6) ______:Tetrad                            F. Comma-shaped, short & bent cells.

7) ______:Single Bacillus              G. 2 short rod-shaped (or oval) cells that remain attached.

8) ______:Coccobacilli                  H. Chain-like pattern of spherical cells.

9) ______:Staphylococci               I. Cluster of 8 spherical cells arranged like a cube.

10) ______:Spirillium                      J. Curved rod that forms a spiral.

11) ______:Sarcinae                        K. Chain-like pattern of rod-shaped cells.

12) ______:Streptobacilli                L. Cluster of many spherical cells in a randomized pattern.

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