ScienceScience Sunday

Science Sunday: Vicious Virus Edition

Most disease-causing (pathogenic) organisms- such as bacteria- exhibit the characteristics of living things such as respiration, excretion, growth etc. This is why viruses are so awesome- reproduction is the only true characteristic of life which they exhibit. Alive or not, these nifty micro-organisms are super interesting, so read on to find out more!


First, the skinny on what viruses really are! They’re actually classified as “obligate parasites” as they can only replicate within the living cells of a host organism. They’re always associated with disease because the cell is destroyed in the process, damaging the host.

Viruses are small. Like teeny-tiny small. They range in size from 20-300 nanometres, and can only be seen with an electron microscope. It has a pretty simple structure- either DNA or RNA surrounded by a protective coat (generally made of protein). They can be transmitted in many different ways- animal bites, contact with bodily fluids or simple coughing and sneezing (so you should always use a tissue, for any of those ickies out there!).


There are several steps required for most viruses to invade their host cell. They use certain molecules to bind to the surface of the cell, and different viruses get their DNA into the host in different ways. One good example of viral replication is the bacteriophage!

I hope you like the lovingly drawn diagram I did for you to explain this (the wonders of MS Paint).

1. First, the virus approaches the host cell (in this case a bacterium).

2. The virus adheres to the cell and thrusts its tail through the cell wall.

3. The virus injects DNA into the host cell.

4. The viral DNA steals the resources of the host (nucleotides) and replicates lots of times due to the direction of the viral mRNA.

5. The viral DNA steals the rest of the resources (amino acids) to form protein coats.

6. The DNA and protein coats form into the fully-fledged viral particles.

7. The host cell bursts, releasing more copies of the virus than MS Paint would let me fit into the picture.

I think it’s awesome, but I’m kind of a nerd. If you’re not already, you should try it. Nerdism is fun and also cool. HONEST.


Viruses are so interesting to learn about- especially the deadly ones. If you want to read more, Google HIV, rotavirus, influenze, hepatitis B or measles (although there are thousands of interesting and terrifying viruses around). Measles are also the cause of many unnecessary infant deaths every year due to the spreading of anti-vaccination sentiments, so it’s one particularly close to the heart of most skeptics. To read more, click here.

Image Credit: Wikimedia Commons

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