📚 Biology Enem E-book http://bit.ly/35OYaeg Free Enem Course https://goo.gl/2rebsa What is a virus: https://cursoenemgratuito.com.br/virus/ Simulation about viruses https://cursoenemgratuito.com.br/simu... Today you will learn with biology teacher Juliana Evelyn Santos, from Curso Enem Gratuito, how viral diseases occur. These are the cycles that viruses perform inside host cells, that is, the reproduction of viruses. Come and teacher Ju will explain! :D #Virus #Biology #Enem Description: 00:00 - Hi, students, how are you? Today we are going to talk about a very small part of the biology content but that is very important for us to understand how viral diseases occur. These are the cycles that viruses perform inside host cells! 00:14 - Before we think about viral cycles, it is important that you remember the essential/general characteristics of viruses and viral structure. We have a class about this, go and watch it and then come back here ;) 00:25 - First, you have to remember that viruses cannot do anything if they are outside of a host cell! So they need to parasitize a cell to use its cellular machinery/cellular structure to be able to produce their own structures. Without this, the virus is an inert particle. 00:47 - And then it can perform two different types of cycles inside a cell. To do this, it needs to enter the cell or at least inject its genetic material. Viruses will have different ways to enter a cell. Basically, we divide them into three different types of viral introduction into a cell. What we will see here, which is often used as an example, is the example of the bacteriophage. The bacteriophage is a virus that will specifically parasitize bacterial cells. This virus has a structure that looks like a little spaceship. In addition to the protein capsule and the genetic material inside this capsule, it also has a tail that will help it attach itself to the cell and inject genetic material into it. This tail is like a needle that will dissolve the cell membrane to inject only its genetic material into the cell, with the rest of the virus remaining outside. 2:00 - But not all viruses have this entire structure. Some of them are enveloped, as is the case with the flu virus. In this case, the technique used is to fuse its envelope with the cell membrane. The envelope of a virus is precisely a piece of membrane from the previous host cell that it was in. So it will fuse these two membranes and thus enter the cell completely, unlike the bacteriophage, where only the genetic material is injected. And there are some viruses that phagocytize the cell. 2:52 - Knowing all this, now let's think about how the virus will act inside the cells. Let's divide this mode of action within the cell into two cycles: the lytic cycle and the lysogenic cycle. The virus can do either one or the other. The lytic cycle is the cycle in which the virus will inject genetic material into the cell, and then, once this genetic material is inside the cell, it begins to enslave this genetic material - the cell understands this genetic material as if it were its own, and it begins to produce viral materials within itself (with its cellular organelles). And so it replicates several viruses within itself, as if it were a factory! There will be so many viruses inside the cell that it ends up breaking and releasing several new viruses into the environment in which it finds itself - and so these viruses will look for new cells to parasitize. So, you can see that in addition to harming the cell during its life cycle, the virus will also kill the cell at the end because it will burst it. 4:27 - And we also have the lysogenic cycle. This cycle occurs when the virus's genetic material is incorporated into the cell's genetic material and remains hidden there, latent; it will not activate any production of viral material. This incorporated genetic material will be replicated unintentionally by the cell itself when it begins cell division. So, for example, a bacterium undergoes cell division and ends up copying the viral genetic material along with its genetic material. The daughter cells will have a copy of this viral genetic material. There, it can remain latent or it can activate and return to the lytic cycle. // Subscribe to the channel // Give it a thumbs up // Leave your comment // Share with friends SOCIAL MEDIA // FACE /cursoenemgratuito/ // INSTA @cursoenemgratuito // TWITTER @enemgratuito Curso Enem Gratuito is an independent channel for disseminating content to support learning and information about programs and opportunities for access to Higher Education.