Question

Are the terms retroviridae and retrovirus interchangeable or is retrovirus a specific virus? Are retroviruses that means a virus that becomes a provirus? I'm confused between terms.

Answer 1

Retroviridae is a FAMILY of viruses.

And all viruses that belong to this family are called "retroviruses."

Answer 2

I thought so. I have a test tomorrow and wanted to make sure I wasn't generalizing a specific virus. Retroviruses refers to any virus that uses reverse transcriptase (in the case of RNA) to integrate itself into the host DNA (provirus), right?

Answer 3

Yes. Retroviruses use reverse transcriptase to make DNA from their RNA.

That's why they're called "retroviruses."
The word "retro" means "backward."
And making DNA from RNA is totally backward.

The PROVIRUS is the part of the virus that gets integrated into the host DNA.
For example, the genetic material of the HIV.

Answer 4

Right. I think I read my notes wrong and thought that retrovirus was the name of a specific virus. Good clarification, thanks. This is semi-related: can you tell me whether the Hepatitis B has a SS RNA or a DS DNA genome? I know that it is partially DS DNA, but my book and my professor have it as a SS (+) RNA virus. What determines it? It is explained as a cycle, and it looks as if it is depends on where it is being replicated. It is a bit confusing.

Answer 5

Good question. I just did a little research here,
and I found that the Hepatitis B virus is actually a DNA virus. Single stranded.

Strange, because there's nothing here that tells me that it's a positive-sense RNA virus.

Answer 6

Hold that thought. I'm reading. This is a strange virus.

Answer 7

That's what my prof said too, but in the powerpoint and the book it is under RNA viruses as an exception. Maybe the book is overcomplicating it. I understand the replication process for it, just not what its genome is classified as.

Answer 8

Well, every article that I pick up tells us that it's partially double stranded DNA.

But since it's only PARTIALLY double stranded,
some articles classify it as a single stranded DNA virus.

It DOES use reverse transcriptase though. You knew that right?

What I don't understand is.....whose RNA is it transcribing?
Its own RNA? That it apparently carries, according to one article I read?

Answer 9

I did know that. It has to transcribe its own mRNA to make DNA, which is its genome, because our bodies don't have the enzymes to make DNA from RNA. My question is why it might be categorized as an RNA virus.

Answer 10

It beats me,
but I'm looking at this picture:
http://upload.wikimedia.org/wikipedia/commons/thumb/0/00/HBV_Genome.svg/425px-HBV_Genome.svg.png

It's a picture of the HBV genome.

We know that it's partially double stranded,
because that RED strand, shown in the middle, isn't quite complete.

Well, that partially completed red strand is labeled as the positive sense strand.
It's the one that has to be completed, inside the host cell.

Do you think that's why the book associates it with positive sense RNA?

Answer 11

Maybe because it can't replicate its genome without mRNA, which is unusual. I don't know why I didn't think of that. DNA is supposed to be able to replicate using its own template, but the fact that it has to use RNA to duplicate probably makes it that it is an "RNA" virus. Annnd the lightbulb goes on.

Answer 12

Well thank you, I believe you just showed me a better explanation.

Answer 13

Are you in college? Or grad school?

Answer 14

I study best when I talk it out with people. I appreciate your willingness to discuss. I am a freshman in college, I'm at a community college, so it's hard to make great study groups.

Answer 15

Oh alright, I see.

Good luck with your test.

You seem to understand the greater part of this material really well.
Are you a biology major?

Answer 16

Thank you, it shouldn't be terrible. I just want to be solid on my understanding. I am a nursing major actually. Which... is pretty much a bio major.

Answer 17

By the way, in response to the other question I asked, I found in my textbook that "an adenovirus has a naked capsid that adheres to its host cell by nestling surface molecules on its capsid into the receptors on the host cell's membrane". I guess they are using spikes and surface molecules interchangeably.

Answer 18

I see! Good to know, about that interchangeability. Thank you.

Answer 19

Quick, dumb question: Hydrogen carries only one electron, right? Like when NAD+ is reduced, it receives two H+ molecules, which each carry only one electron?

Answer 20

Yeah that's right. One electron, one proton.

Answer 21

A hydrogen ion has two electrons, right?

Answer 22

Actually, no electrons.

Hydrogen ions are hydrogen atoms that have given up their single electron.

So they're left with just a single proton,
which makes them positively charged.

Answer 23

I thought ions could be either positive or negatively charged. So either gained an electron or lost one.

Answer 24

Yep, they can be either positively charged cations,
or negatively charged anions.

But I can't think of any cases where hydrogen gains electrons, and becomes an anion.

I've got these articles here too:

http://www.ehow.com/info_8629128_properties-hydrogen-ions.html

http://www.lsbu.ac.uk/water/ionish.html

Answer 25

H+...that's right. It's obviously my bedtime. I just finished explaining potential energy of electrons to another member... I'm fired.

Answer 26

Mmm hm. Even superwoman needs to sleep.

And so do I, frankly.

Answer 27

Far from. That's why I came to this site! Best study tool EVER. I can't tell you how much I appreciate discussing with someone (smarter) than me to make sure I am doing it all right.

Answer 28

I do think that, overall, you're more knowledgeable in biology than I am.
I mean you're one of the few people on this site who seems to have a solid grasp on it.

When I talk to you, I realize that I've yet many things to learn.
It's humbling. Refreshing.
And so I understand your appreciation. I share it.

In any case, I'm happy to be of help.

Answer 29

I have actually only last semester taken a true biology course, and this semester I'm in microbiology and A&P. I never took a good biology class in high school. I have a solid grasp on some things, but you are much father along in your studies and exposure.

Likewise! I will be coming back here for all my studying! Answering questions has forced me to explain things in a way that others will understand and to be sure I understand it myself.