Hello everyone. In this lesson, we are going to be talking about the different groups and classifications of viruses depending on the amount and type of genetic material that they have. So, viruses, even though they are not alive, are going to have genetic material that contains the blueprints for new viruses. And they can either have a DNA virus or an RNA virus. Meaning that they can have a DNA genome or an RNA genome. Now, these different genomes can come in the form of double stranded DNA or RNA or single stranded DNA or RNA. So first, let's talk about double stranded DNA viruses and double stranded RNA viruses. Double stranded RNA viruses are going to have a genome that's very similar to ours. They're going to have double stranded DNA to make up their genetic material. And because it's so similar to our genome, whenever the virus enters into the cell, it can easily be replicated because it often replicates with the genome during the S phase. Double stranded DNA viruses often integrate themselves into our genome, so that anytime we replicate our genome, the viral genome is replicated as well. Now, they're going to infect a wide array of organisms including us, including bacteria, including all sorts of organisms except land plants, which I always thought was interesting. Land plants don't have double stranded DNA viruses. Now, there's also double stranded RNA viruses. Double stranded RNA viruses are not as common as single stranded RNA viruses, but they're still very important. Double stranded RNA viruses are going to be a little bit different. They are going to enter the cytosol, and because they are double stranded RNA viruses, they can serve as a template for synthesis. They can actually serve as a template to create the viral proteins that are needed because it's already RNA, and it's already going to have RNA molecules that can be translated. So, this allows the viral enzymes to be made, and then these viral enzymes are made, and then the viral genome can be replicated as well. And this is going to include a whole bunch of organisms that can be infected including fungi, plants, vertebrates, bacteria, and insects. So a ton of different organisms are infected by double stranded RNA viruses. Now, we're going to talk about single stranded RNA viruses, which are going to be the most common type of virus that you will ever hear of. Now, if you guys wanted some examples of Double or if you wanted some examples of DNA viruses, Smallpox is a DNA virus, herpes is a DNA virus, and chickenpox, I also believe, is a DNA virus. Most viruses we're familiar with are going to be RNA viruses and most of those are going to be single stranded RNA viruses. Now, I'm going to go over this topic first before we talk about single stranded RNA viruses because single stranded RNA viruses can come in 2 forms, but I wanna go over a concept before we talk about those two forms. So, what do we have here? Do you guys know? Well, this is the process of transcription whenever we already learned about whenever we learned about DNA expression. So, this is the process of transcription and this mRNA in blue is being made by the RNA Polymerase actually reading the genetic code, the DNA, and building an mRNA strand off of this genetic code. So this is the DNA, and then we have our RNA polymerase. Now, whenever we talked about creating mRNA, we talked about the coding DNA strand and the template DNA strand. Now, there are many names for the coding strand and there are many names for the template strand. You guys might also remember that the coding strand can also be called the sense strand. And it's also called the positive strand. For whatever reason, the coding strand has 3 different names. Remember, the coding strand is going to have the same exact code as the mRNA. So the coding strand equals the code of the mRNA. They have the same exact code. Now, we also have the template strand here, which is very important. The template strand also has its own unique names. It's either called the template strand. It's either called the antisense strand, or it's called the minus strand. Now, I know that it sucks that we have to remember all these different names of these DNA strands, but they are going to become very useful. Let me rewrite that since you guys can't really see it. So, the minus strand. Okay. So, the template strand is called the antisense strand and the minus strand. And the template strand is going to be complementary to the mRNA. So, the template strand is complementary to the mRNA. And that is because the template strand is utilized to build the mRNA. So they're going to be complementary to each other while the coding strand and the mRNA are going to be exactly the same code. Now remem
17. Viruses
Viruses
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