This is part two of the organelles. Okay, so let's move on to the ribosomes. So the ribosomes are a major site of protein synthesis.
And we already explained that earlier, right? So the translation of mRNA to proteins, most of it will happen in the ribosomes. Okay, and take note, the ribosomes can be found in different places. Okay, they can either be found in...
the rough endoplasmic reticulum, and these ribosomes which are embedded in the RER are known as the bound ribosomes. They can also be found in the cytoplasm, which is the fluid quote-unquote space in the cell itself. Those are the free ribosomes.
So we already mentioned the endoplasmic reticulum. So there are two major types of endoplasmic reticulum. The first one we already mentioned, right? RER, or rough endoplasmic reticulum, and it's rough because it's studied with ribosomes, or the smooth endoplasmic reticulum, which does not have ribosomes.
But generally, the endoplasmic reticulum is for the synthesis of different substances. And as to what these substances are, of course, will depend on if the ER is smooth or if the ER is rough. For smooth endoplasmic reticulum, so in this diagram here, this would be the smooth endoplasmic reticulum since it's not studied by ribosomes. It's mostly for the production of lipids. So lipid synthesis in the cell will mostly occur in the smooth ER.
Of course, it's not just the only function that the SmoothER performs. It can also be for the breakdown of carbohydrates, for breaking carbohydrates down into their more basic forms, or into their more basic components. Or, the SmoothER can also be used for processing certain chemical substances. Processing in terms of what? Well, it depends on the cell type.
But a very good example of this is found in the liver. So the smooth ER of the cells that are found in the liver are capable of breaking down certain substances, like, say, whatever drugs you take in or wastes that are produced by the body. So the smooth ER also plays a role in detoxification in this case. What about the rough ER?
Well, we already mentioned this earlier, right? The rough ER is mostly for protein synthesis through the embedded ribosomes. So mRNA protein translation occurs in the ribosomes of the rough ER. And of course, the rough ER is also for synthesizing membranes. And then next we have the Golgi apparatus.
The Golgi apparatus is responsible for processing different products that are produced by the cell. More specifically, the Golgi apparatus receives products, processes these products, and after the products have been processed, ship these products off into their respective destinations. How does this happen?
Well, The Golgi apparatus has a side for receiving products, and this side is known as the cis-phase. The products are transported into the cis-phase within vesicles, within structures known as vesicles. A vesicle will contain products, and these products are received by the cis-phase. Then, of course, there are multiple structures known as the cisternae within the Golgi apparatus. So imagine these to be like the folds, okay, shown here.
Okay, so modification and processing of the products that were received by the cis-phase occurs in the cisternae until the product reaches the trans-phase. When it gets to the trans-phase, then it is shipped off to other destinations also by using vesicles. Okay, so in a nutshell, A vesicle enters the cis-phase, the product is processed in the cisternae and shipped off. from the transphase using more vesicles. So we keep talking about products, right?
So what products are processed by the Golgi apparatus? Well, an example of what can be processed by the Golgi, we have the proteins that are produced by the rough endoplasmic reticulum. Okay, so for example, the RER produces a protein, it's shipped off to the Golgi apparatus in a transport vesicle, it's further processed in the cisternae, and it's transported to other directions or other destinations.
And there are three main destinations that the Golgi apparatus transports off to. It's either it goes to or the product goes to the lysosomes, to the plasma membrane, or to the outside area of the cell. That's it for the Golgi. Oh, not yet. Aside from the modification of proteins that I mentioned earlier for the RER, it can also synthesize carbohydrates.
And we mentioned the lysosomes earlier, right? So what are the lysosomes for? Lysosomes generally are for digestion and the disposal of waste. Okay, and how do the lysosomes do this? So they do this by fusing with different structures in order to either digest the structure or dispose of the waste that are found in that structure.
And what do they fuse with? For example, let's say that the cell has damaged organelles. Okay, so it's the lysosome's job to break down these organelles and remove them from the cell.
What else? So it can also be for the breakdown of food or the breakdown of any foreign bodies that are found within the cell. What foreign bodies are we talking about?
Let's say, for example, viruses get into the cell. So it's the lysosome's job to break down these viruses in order to neutralize the threat to the cell. And finally, we have the mitochondria. And yeah, I know what you're thinking, powerhouse of the cell.
Well, I mean, it produces ATP, right? The mitochondria produces ATP. And it's also a membrane-bound organelle. But we'll discuss more about the ATP production process in a future lesson.
Okay? Specifically, I think it's lesson three. For, yeah, I'll recheck.
But I think it's lesson three. Okay? So aside from producing ATP, the mitochondria also plays a role in apoptosis or programmed cell death. It also plays a role in detoxification or removing toxins from cells, but this doesn't happen in all cells.
And it also plays a role in signaling or cell-to-cell communication or signaling within a cell. And that's... it for this lesson.
Now, if you have any other questions, please post them in the question discussion board. And please don't forget to answer the points for discussion for this lesson. Okay, so all in all, I think this lesson had nine parts, if I'm not mistaken.
So I hope you watch all of them. And if you have time, watch them twice or even thrice. to help you understand them more. Okay, so that's it for lesson one, and bye-bye.
Have a good day.