in this video we're going to continue to talk about animal viruses and animal virus infections. By specifically focusing on reverse transcribing virus synthesis and replication. And so reverse transcribing viruses are specific types of RNA viruses that encode the enzyme called reverse transcriptase tastes. And so reverse transcriptase is an enzyme that serves as an RNA dependent DNA preliminary race. Which means that this is an enzyme that uses RNA as a template to make DNA. And really this is the reverse of transcription which is really where it gets its name from reverse transcript taste as the reverse of transcription. And so here in this video we're mainly going to be focusing on retro viruses. And so retroviruses are specific types of reverse transcribing viruses that have a plus S. S. RNA genome or a plus single stranded RNA genome. And of course because they are reverse transcribing viruses they will also have the enzyme reverse transcriptase. And so after entry into the cell the retrovirus is going to inject both the PLUS Ss RNA genome as well as the reverse transcript taste. And so the reverse transcriptase enzyme is able to use the plus S. S. RNA genome as a template in order to make minus S. S. DNA. And so if we take a look at our image down below, over here on the left hand side, we're showing you that upon entry into the host cell. The retrovirus will inject its genome which is a plus S. S. RNA genome. And it will also inject the enzyme reverse transcript tastes. And so reverse transcriptase. The enzyme is able to use the plus Ss. RNA as a template to build a minus S. S. D. N. A. And so it is using the RNA to build D. N. A. Then the minus S. S. D. N. A. Is going to be used to build a compliment DNA strand to form the plus minus double stranded DNA or D. S. D. N. A. And so notice down below that the minus S. S. DNA. The single stranded DNA is going to be used to build the complementary strand. So that is now a plus minus double stranded DNA molecule. And from here the plus minus double stranded DNA molecule can be transcribed to form more plus S. S. RNA, which recall is a messenger RNA. And that messenger RNA can be translated to form viral proteins. And or it could be used to replicate the original plus S. S. RNA genome. And so remember that the original genome of the virus that is injected is always going to be regenerated over uh at the end of genome replication. So we have another plus SSR and over here. And so another important feature to keep in mind is that this plus minus double stranded DNA molecule that's right here. Uh it can also have the ability to integrate itself into the host cell's chromosome in order to become latent or dormant or silent inside of the host cell. And again it can replicate along with the host cell as the host cell replicates. And so this year concludes our brief introduction to reverse transcribing viruses and how they synthesize proteins and replicate their genomes. And so we'll be able to get some practice applying these concepts as we move forward in our course. And so I'll see you all in our next video.
2
Problem
Problem
Which of the following characteristics correctly describes retroviruses?
A
They are made up of only a single protein.
B
They can only reproduce by infecting bacteria.
C
They have single-stranded DNA that acts as a template for DNA synthesis.
D
They have single-stranded RNA that acts as a template for DNA synthesis.
3
Problem
Problem
A retrovirus _____.
A
Is a DNA virus.
B
Integrates viral DNA into the host chromosome.
C
Requires the viral protein replicase to replicate its genome.
D
All of the above.
4
Problem
Problem
The human immunodeficiency virus (HIV) is a retrovirus. HIV will not be able to integrate its viral genome into the host cell's genome unless it carries which enzyme in its viral particle?
