#Biology #Cytology #Vesicles Class aimed at high school and ENEM students about cytoplasmic vesicles. Script below. Due to lack of space, it is not possible to include the video bibliography. If you want, get in touch and I will send it. Video script: In your cell, almost all material transported here or there does not come loose, but through small bags that move in the cytoplasm. One of the main roles of these bags is to transport, but some have special characteristics such as enzymes inside them, so in addition to transport, they also digest. But let's take it easy and understand more about what this is. These bags are called vesicles, they are essentially a small ball made of a membrane with a phospholipid bilayer that can originate from various parts of the cell, but the best known come from either the plasma membrane, the ER or the CG. They can be separated into groups depending on their function, so let's talk about some of them: Starting with transport vesicles: as the name suggests, they transport substances from one place to another in the cell, such as the vesicles that go from the RER to the CG. Next, we have secretory vesicles, which are those that will take some cellular product and transport it out of the cell, such as hormones, neurotransmitters, and others. They are further subdivided depending on the cell we are talking about, such as nerve cells having synaptic vesicles to help with synapsis, endocrine tissue cells have endocrine vesicles to release hormones, bones and cartilage have calcium mining vesicles, and so on, each with its own vesicle. We also have vesicles with other functions, such as gas vesicles, endosomes, and several others that may be present in cells. However, since this is a short class, we will focus on three special vesicles from now on. Starting with one of the most famous, the Lysosome. This vesicle is so important that it has the status of an organelle defined by several authors, and it is indeed very important. It was discovered in a study of liver cells in 1949. In this study, researchers (Christian de Duve) tested a specific enzyme that reacted to insulin and, after several days of testing, they realized that the enzyme was surrounded by a membrane, like a bag, or as we mentioned before, like a vesicle. However, it was only given the name Lysosome in 1955 because other digestive functions of this strange vesicle were being discovered. Later, the same researcher who discovered the Lysosome in 1949 received the Nobel Prize in 1974 for his discovery. But what is the importance of this organelle? Well... Lysosomes are vesicles formed in the GC that take enzymes from the RER to digest macromolecules in the cells, such as proteins, polysaccharides, lipids and others). It works more or less like this: The RER sends specific enzymes to the GC, where these enzymes are placed inside special vesicles called late endosomes (made by endocytosis) (TUMB CLASS INTRA/EXTRA TRANSPORTATION). The combination of these late endosomes with these enzymes makes the enzymes mature with the addition of some chemical components, increasing the enzyme's potency. Once at maximum potency, the lysosome is ready. Then it detaches from the GC and goes to work. One of the most important things is that its membrane composition is made specifically to hold the action of these enzymes inside this bag, protecting the rest of the cell from self-decomposition. In addition to this characteristic, lysosomes can associate with other vesicles from intracellular transport, such as pinosomes and phagosomes, helping to digest almost everything that enters the cell. Finally, another function is their relationship with autophagy. A process that occurs when the cell is at a point where it can no longer obtain nutrients to maintain regular processes, or has some defect that prevents its regular function. In both cases, it understands that it is better to destroy itself and recycle its material so that other cells can use it and survive. This function is very important for the cell, and it is the lysosomes that perform this function. Animal cells have a large number of lysosomes, but plant cells have a slightly different lysosome, and we will talk about them now, the famous vacuoles. In essence, vacuoles are lysosomes 2.0, they do everything that animal lysosomes do, but in addition, they have some other capabilities. The first is the ability to store substances, as long as they are related to the digestion and excretion of cells. Another important fact is that they are very large organelles, in fact they occupy the largest space in a plant cell, and this is very good because another function of them is to regulate the osmotic pressure of plant cells, as we discussed in the class on osmosis in plant cells (TUMB).