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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


Cell Inclusions

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in this video, we're going to begin our lesson on cell inclusions. And so inclusions are defined as cytoplasmic molecular aggregates. Or in other words, aggregates of molecules in the cytoplasm and they can be very diverse in both their structure as well as their function. And we'll be able to talk about some of the different types of inclusions down below in this table. Now some inclusions are stored as insoluble Granules, whereas others are enveloped by proteins, a lipid membrane or both proteins and a lipid membrane. Now, Granules are defined as small particles that are barely visible by a microscope, and in many cases Granules are referring to vesicles small little lipid bubbles now down below in this table, once again, we have a bunch of different types of inclusions. Now this does not include all of the different types of inclusions. It only contains some of the more common types of inclusions that are usually tested on by microbiology professors, and so notice that we have the inclusion type over here, on the far left, and the function over here in the middle, and then a corresponding image on the far right. So the first type of inclusion type that we have are the storage Granules, which are going to be Granules that are used for storage purposes almost like a kitchen pantry in a way where you can store items in your kitchen pantry for use at a later time whenever you need it. And so you can see here that storage Granules are going to be aggregates of large polymers that are in excess inside the cell. And so when the cell has a light, a lot of a particular type of molecule, it can store it as these storage Granules and then later at a different time, if that molecule starts to get low, then they can use the storage Granules as a source to be able to get more. And so there are many types of storage Granules, including carbon Granules which are going to be storing carbon to be used later as an energy source. There are also polly phosphate Granules which are going to be storing phosphate groups, inorganic phosphate groups for later use and bio synthesis to make things like nucleotides and uh stuff like that. There are also sulfur Granules which are going to be storing sulfur and bacteria that actually use sulfur to generate energy. And so you can see over here these little bubbles that are inside of the cells represent storage Granules that can be inside of cells. Now, the next type of inclusion type that we have our car boxes owns and car boxes owns have Ceo to fixing enzymes that are going to be enveloped by a protein shell. And car boxes um serve as the location of carbon fixation and many bacteria. Now, the next type of inclusion that we have our gas vesicles and as their name implies, these are going to be gas particles enveloped by a protein shell. So they're going to contain gas. And these gas vesicles helped to control the cells buoyancy which is really just the ability to float in aquatic environments. And so uh this buoyancy control allows them to change their elevation within an aquatic environment to get to an area that has more light or more nutrients or less light and you know, more nutrients gas vacuums uh huh are basically just groups of gas vesicles in the cell. And so the gas vacuum rules are a little bit larger than the gas vesicles themselves. Uh And last but not least, the final type of inclusion that we have here in this table are the mag netto. So and the magnetic soames are intracellular chains of iron containing molecules that are enclosed within a membrane. And so these magnetic stones are used by the cells to orient themselves with the earth's magnetic field. And so here in this image, you can notice there is this chain of these iron containing molecules and they orient. They help to orient the entire cell with respect to the Earth's magnetic field so that the bacteria can have a sense of direction of what is up and what is down and things of that nature. And so this year concludes our brief lesson on cell inclusions and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Which of the following statements about gas vesicles is TRUE?


Which of the following inclusion bodies contain iron?