• Question: Why do cells explode when they have so many virus in it?

    Asked by anon-256945 on 16 Jun 2020.
    • Photo: Anabel Martinez Lyons

      Anabel Martinez Lyons answered on 16 Jun 2020:

      Great question – you’ve probably seen some videos of viruses bursting out of a host cell. What is happening is that the host cell is being destroyed from the inside out. The viral life cycle begins with infection of a host cell, and ends with that cell dying and its outer membrane (called the plasma membrane) breaking. Only then, can newly synthesised virus ‘get out’ and go on to infect and kill other cells. Here’s a really quick video that outlines the life cycle of a virus, which you may find helpful: https://www.youtube.com/watch?v=uIut0oVWCEg. Thanks for the interesting questions, Iago! 🙂

    • Photo: Luke Hillary

      Luke Hillary answered on 16 Jun 2020:

      Great questions Iago! Not all viruses make cells explode. Some can live peacefully inside a cell until reactivated. Others can pass from one cell to another through passages between them. Some viruses force the host cells to make proteins that break down or make holes in the cell membrane. This weakens the cell membrane to the point where they pop, and release the virus particles to go on and infect other cells. Some other viruses, like coronavirus take some of the host cell membrane with them, a bit like pinching off a piece of blu tack from a big ball. One of the things that’s always fascinated me about viruses is how they do all this by taking over a cell’s own functions, and forcing it to work to produce more viruses.

    • Photo: Melanie Krause

      Melanie Krause answered on 16 Jun 2020:

      Hi Lago,
      Great question!
      Viruses basically turn all processes in the cells upside down.. all energy of the cell is directed towards making more virus. So on the one hand the cell its just SUPER full with virus! I study viruses myself and our lab could actually show that right before cells break apart they are so full with viruses that they are heavier than uninfected cells and you can measure that on a very sensitive scale.
      The other aspect is that the virus takes away energy from the cell that it usually uses to keep the cell membrane intact and maintain it.
      So its basically the cell is just so full that there is no space and the cell is so weak that it can’t keep the membrane up.

    • Photo: Aisling Ryan

      Aisling Ryan answered on 16 Jun 2020:

      Great question!
      I think Luke has answered this really well. Viruses aren’t fully alive, so they need to use human cells to keep them alive. So when a person gets infected with a virus, the virus will go inside the human cells and once they are nice and all settled and cosy they will make lots and lots of new viruses so that the person’s body is overwhelmed and can’t fight back quickly enough to kill the virus. As mentioned by all of the scientists who have already answered your question, not all viruses will make the human cell explode, but every virus wants to spread itself to as many other cells as possible. So, in the case of some viruses they will kill the human cell by making it explode, and this of course is going to cause a lot more damage to the person than if the virus didn’t explode the cell and used some other way of spreading itself from cell to cell.
      Did you know that when a person infected with a virus coughs or sneezes this is another way of the virus spreading itself to new cells? Except this time it is an entirely new person they are spreading to!! Which, of course is why everyone is social distancing, wearing face masks (if they can), and washing their hands lots- so that we don’t let the annoying virus infect more cells!!

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