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
Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components.
In animal cells, which of the following organelles contains these hydrolytic enzymes?
A
Rough ER.
B
Central vacuole.
C
Smooth ER.
D
Lysosomes.
E
Golgi apparatus.
3
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.
4
concept
Central Vacuole
Video duration:
4m
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Video transcript
In this video, we're going to talk about yet another digestive organelle of the endomembrane system, and that is the central vacuole. Now, the central vacuole is a large membrane enclosed vesicle found inside of plant cells. Central vacuoles, they are not found in animal cells. They're really only found in plant cells. Now central vacuoles, they actually have a lot of different types of functions, but those functions include degrading and recycling molecules. So they're part of the digestive organelles for that reason. Now other functions of the central vacuole include filling up with water to exert what's known as turgor pressure against the cell membrane. So let's take a look at our image down below to get a better understanding here of this central vacuole. So over here on the left hand side, notice that we're showing you our representation of a plant cell, and recall central vacuoles, they're really only found in plant cells, not in animal cells. And so you can see the central vacuole is this blue structure that we see right, here. Okay? And we have it labeled as the central vacuole. And so over here on the right hand side, we're showing you some other representations of plant, and plant cells. And so notice that in this image over here, notice that water is actually leaving the cell. We have the arrows going in a direction where the water is leaving the cell. And so notice that the plant cell's plasma membrane, which is right here, it's not really exerting any pressure onto the cell wall, and the cell wall is the surrounding wall that you see right here. And so the plasma membrane or the cell membrane, which we have in red, when water is leaving the cell, it doesn't exert pressure on the cell wall, and so that means that it's going to have very very low turgor pressure over here. And so when a plant has low turgor pressure, it's not going to be in a healthy state, and so that can cause a plant to wilt, like this wilted plant that we see here. And so, ultimately, this could lead to a cell dying. Now over here on the right hand side, notice that we're showing you the arrows going into the cell, showing that water is going into the cell and filling the cell up with water. And so one of the roles of the central vacuole is to fill up and store water, and what you'll notice is that with all of this water going into the plant cell, the cell's plasma membrane is expanded, and you can see the cell's plasma membrane is being traced right here in red. And, I'll do it here with a thicker color so that you can see it easier. It's being, right here in red is where the plasma membrane here. And so the plasma membrane is right up against the cell wall, and so the plasma membrane is exerting pressure on the cell wall, which means that when water is going into the plant cell, there is going to be high turgor pressure. And so turgor pressure can allow plants to be upright and to have their normal healthy structure. And so this here concludes our brief introduction to central vacuoles, and we'll be able to get some practice applying these concepts as we move forward throughout our course. So, I'll see you all in our next video.
5
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.
6
Problem
Problem
Which type of plant organelle often occupies the majority of the cell's volume?
A
Food vacuole.
B
Plant vacuole.
C
Central vacuole.
D
Contractile vacuoles.
E
Chloroplasts.
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