What's a virus, anyway? The bare-bones basics

It's hard not to draw analogies though.

For example, the covid-19 virus's RNA ends with AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA (33 As) which, as someone pointed out, looks suspicially like a "NOP sled"[1] (i.e. so that a protein coming in hot can hit anywhere on the sled and then slide down to the actual information)

[1] https://en.wikipedia.org/wiki/NOP_slide

The cliff notes version of it is that DNA encodes the information on how to build proteins.

https://en.wikipedia.org/wiki/Central_dogma_of_molecular_bio...

Proteins are built out of a chain of aminoacids. There are 20 different kinds of aminoacid, and the particular sequence of aminoacids determines the shape of the protein, and therefore its biological function.

https://en.wikipedia.org/wiki/Amino_acid

To build a protein, the cell uses a strand of RNA as template. The RNA consists of a sequence of 4 kinds of bases (A=Adenine, C=Cytosine, G=Guanine, U=Uracyl) and there is a genetic code that maps each group of 3 RNA bases into one aminoacid. For example, "AGC" corresponds to serine, "AAG" means lysine, and "AGCAAG" means serine followed by lysine.

https://en.wikipedia.org/wiki/Genetic_code

DNA is built of similar pieces as RNA. The main difference is that RNA is single stranded, while DNA is double stranded with that famous double helix structure. Additionally, DNA uses T=Thymine in place of U=Uracyl.

DNA acts a store of information. Each gene contains the genetic sequence that describes how to build one protein. When a gene is active, the cell copies that part of the DNA into a messenger RNA, and then uses that RNA as a template to build the protein in question.

Every cell in the body has the exact same set of genes, but they differ in what genes are active at each time.

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Now on to viruses...

The Coronavidus is an RNA virus. Each individual virius is a little ball made of proteins and lipids, encasing a genome made of RNA.

By itself the virus is inert, but once that RNA finds its way to inside a human cell, it behaves like a fork bomb. The cell translates the viral RNA into proteins, just like it would with our own RNA. One of the proteins is a polimerase enzyme, which then makes even more copies of the viral genome. Soon, there are thousands of copies of the virus. Additionally, the viral genome also encodes the structural proteins for the capsule of the virus, including the "spike" protein that gives coronaviruses their signature look.

A poly A tail is at the end of the transcript, not the start. This is a perfect example of the dangers of analogies because this one is completely incorrect. Poly A tails protect RNA from degradation. A ribosome will not bind to that part, it will bind to something within the 5' untranslated region on the other end of the genome) ribosome binding site, kozak consensus sequence, etc). If you bound to the poly A tail and slide "down," you'd just slide right off the end of the gene.

Definitely nothing wrong with trying to find things that look similar across fields and try and gain differentiated insights, it's certainly an admirable thing and an important part of making many discoveries. But a first principles understanding of the structure of DNA, what a 5' end and a 3' end is, and how transcription/translation works (all bio 101 type stuff) would provide a much better foundation to do that with. You don't need a degree in biology to know the basics, just like you don't need a degree in CS to know the basics, but it's worth learning the basics if you want to get an understanding of the field or work with it.

https://en.wikipedia.org/wiki/Polyadenylation

I have a CS background and for me the best explanation of how life fundamentally works was the MIT 7.00x "Introduction to Biology - The Secret of Life" course. It is absolutely amazing, requires only high school level knowledge and covers so many incredible stuff that I cannot possibly list all of it here. And not only is this course teaching you how stuff works but also the history behind it, how we, humans, figured it out. And, it's free and available online!

If you ever wanted to get deeper into biology than reading news articles, I cannot recommend this course enough.

Edit - I'll concede that analogies are absolutely fun haha. They might be useful to come up with when you yourself are trying to better understand something by drawing connections to other things you know and all. But I don't think they're ideal for being taught the subject. And again, for a layperson, analogies are totally fine if you just want a surface level understanding of "oh, mitochondrias are powerhouses of the cell." But if you want to do anything with that, beware the dangers.

The second analogy is ok, but again not really great if you want to understand what's actually going on. If you just want to get an intuition that DNA has something to do with storing information, as long as that comes with an understanding that information evolves (biology is really the study of evolution in many ways), that's probably more than enough for a layperson. But it's a dangerous understanding if you plan on using it as a foundation to try and explore more complicated topics in biology. There's no need to do so, but if you are going to, it's far far better to spend the time getting the correct first-principles understanding and get rid of this idea of "DNA as source code" so you can better grapple with the subject.

I don't think the first analogy makes much sense since it makes nucleotides the sort of active agents here and needlessly focuses on individual nucleotides when codon triplets are what are involved in coding for proteins (probably better to, if you have to use an analogy, treat nucleotides as letters instead of words). And, especially in the context of this thread, neither analogy build the understanding needed to really dive into what RNA is, which is important for understanding what RNA viruses are, and what the coronavirus is.