system
Given the following post, respond as if you're commenting on Reddit:
human
How do bacteriophages have the energy to inject their DNA into cells?

I've been curious for a long time about how viruses, specifically bacteriophages, are able to move, seemingly on their own, once they are attached to a cell. I am talking about the plunging that they do in order to inject their DNA into a cell. This seems like much more focused movement than what they do until they come around to the right kind of receptor, right?

After some Wikipedia reading, I came across this paragraph:
*Myovirus bacteriophages use a hypodermic syringe-like motion to inject their genetic material into the cell. After making contact with the appropriate receptor, the tail fibers bring the base plate closer to the surface of the cell known as reversible binding. Once attached completely irreversible binding is initiated, the tail contracts, possibly with the help of ATP present in the tail, injecting genetic material through the bacterial membrane. Podoviruses lack a elongated tail sheath similar to that of a myovirus so will instead use its small tail fibers in a teeth-like manner to enzymatically degrade a portion of the cell membrane before inserting its genetic material.*

However, I do not understand reversible nor irreversible binding, and I'm hoping someone here might be able to explain this in slightly less technical terms. Here's the question as succinctly as I can pose it: How to bacteriophages summon the energy to plunge into a cell?

Thanks for considering this question!
gpt
Antiviral biologist here, not a biochemist though.  It's a series of chemical reactions similar to the way proteins can change their conformation as a result of a single binding.  In the simplest terms, when the phage connects to the membrane, the difference in polarities at the binding site creates a cascade of changes into what is the most ideal organization of atoms in the structural protein sheathing.  These changes eventually lead to the expulsion of the DNA from the structural protein and into the cell.

The reversible vs irreversible, in this case, just correspond to different phases of binding.  Reversible is before the 'hypodermic needle' section has made contact, where as irreversible is after, as the cell's membrane has been penetrated.