Endomembrane System: Digestive Organelles - Video Tutorials & Practice Problems
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1
concept
Lysosomes & Peroxisomes
Video duration:
5m
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Video transcript
In this video, we're going to introduce some digestive organelles that are part of the endomembrane system. And so recall in our previous lesson videos, we mentioned that some of the organelles of the endomembrane system are more specialized for cellular digestion or essentially breaking things down inside the cell. And so there are 2 specific organelles that we're gonna focus on here in this video, and those are the lysosomes and the peroxisomes. Now lysosomes are vesicles, acidic vesicles that carry digestive enzymes, And these digestive enzymes are responsible for breaking down and recycling food, cellular debris, bacteria, and damaged organelles, and all kinds of different things that are inside of the cell. So lysosomes are important for breaking down and recycling things. Now lysosomes, they're primarily only found in animal cells, so they're not really found in plant cells. And lysosomes are going to originate at the Golgi apparatus. Now, on the other hand, peroxisomes are also vesicles, just like lysosomes are vesicles. And peroxisomes, they also contain enzymes as well, just like lysosomes also contain enzymes. And so lysosomes and peroxisomes, they have some similarities, but they're also different from each other because peroxisomes, they're mainly used for breaking down toxic compounds. They're used for breaking down toxic compounds, such as, for example, hydrogen peroxide or h 2 02 is a toxic compound inside of the cell, and peroxisomes are really important for helping to break down hydrogen peroxide because, once again, it can be toxic. And peroxosomes are also really important for breaking down fatty acids as well. So that's another important function of peroxisomes. Now unlike lysosomes, which are only found in animal cells, lysosomes are only found in animal cells, peroxisomes on the other hand, they're found in all eukaryotic cells, which includes both animal cells and plant cells as well. And also unlike lysosomes, which originate at the Golgi apparatus, peroxisomes are going to originate at the rough endoplasmic reticulum or the rough ER. So let's take a look at our image down below to better distinguish between these lysosomes and peroxisomes. And so the top image here is specifically focusing on lysosomes. So notice that the lysosome is a vesicle. It's a very acidic vesicle or very acidic membrane bubble, tiny little membrane bubble. And on the inside of this And so the lysosome is capable of fusing with other vesicles or other membrane structures. And so notice here we're showing you a vesicle here that's carrying cellular debris, and the cellular debris is basically the contents that you see on the inside of this vesicle. And so the lysosome is, going to be capable of fusing and merging with other vesicles. So here you can see the fusion, so that the internal compartments are combined. And so what this means is that the digestive enzymes are going to be exposed, to the cellular debris. And so that means that the digestive enzymes can break down the cellular debris into its tiny little components, and so that helps to break down and recycle the components within the cell. Now peroxisomes on the other hand, which we're focusing on down below right here, notice that there are also these vesicles, and, they also contain enzymes as well, which are represented by these little green structures that you see. However, the enzymes in peroxisomes, they're specific for breaking down toxic compounds, like this, representation right here is supposed to be a toxic compound. And so, it can break it can fuse peroxisomes can fuse with the toxic compound and then break down the toxic into a component that is no longer toxic. And also peroxisomes are really important for breaking down fatty acids as well, as toxic compounds. And so this here really concludes our introduction to lysosomes and peroxisomes, and we'll be to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
2
Problem
Problem
Which of the following organelles are involved in cellular digestion?
A
Golgi Apparatus & Vesicles.
B
Nucleus & Nucleolus.
C
Lysosomes & Peroxisomes.
D
Smooth & Rough Endoplasmic Reticulum.
E
Nucleus & Chloroplasts.
3
concept
Central Vacuole
Video duration:
4m
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Video transcript
In this video we're going to introduce yet another digestive organelle of the endomembrane system and that is the central vacuole. And so the central vacuole is really just a large membrane enclosed vesicle in plant cells And so the central vacuole is not going to be found in animal cells. Again, the central vacuole is a feature found in plant cells. Now the central vacuole can actually have several diverse functions. However, some of those functions include degrading and recycling molecules which is why the central vacuole can be considered a digestive organelle. Now other functions of the central vacuole include filling up with water in order to exert what's known as turgor pressure against the cell membrane. And so if we take a look at our image down below we can get a better understanding of this central vacuole. And so notice on the left hand side over here we're showing you our representation of a plant cell and we know that plant cells have a cell wall and they also have several organelles which are going to include a central vacuole. Now notice over here we're showing you a plant, whose cell wall is right here around the perimeter, but notice that this plant cell membrane is not right up against the cell wall. And so in this scenario right here what's happening is water is going to be leaving the plant cell and so you could draw an arrow coming out of this plant cell and say that water or h two o, would be leaving this plant cell. And so when water leaves the plant, the plant is going to somewhat become dehydrated and the plasma membrane is gonna be shriveled up and so the plasma membrane will not be exerting pressure on the cell wall. And so what we can say is that under these conditions, there will be low turgor pressure. And when the turgor pressure is low, this can cause plants to wilt as you see here and a wilted plant is not going to be thriving as it should and so this plant here is likely to die very soon under these conditions of low turgor pressure. Now, notice over here on the right hand side of the image, we're showing you another plant cell again its cell wall is around the perimeter, but notice that this time the cell membrane is going to be exerting pressure up against the cell wall. And notice that the central vacuole is actually much much larger over here whereas on the left hand side it's much smaller. And the central vacuole, again one of its roles is to fill up with water to exert turgor pressure. And so, over here in this scenario what we're saying is that there is high turgor pressure. And the high turgor pressure allows the plant to take on an upright healthy position so that that plant can thrive and survive very well. And so, this here concludes our brief introduction to the central vacuole 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.
4
Problem
Problem
Which are recycling centers for the cell?
A
Ribosome and Golgi apparatus.
B
Endoplasmic reticulum and chloroplast.
C
Mitochondria and nucleus.
D
Central vacuole and lysosome.
E
All are correct.
5
Problem
Problem
Which type of plant organelle often occupies the majority of the cell's volume?