Week 8 — Microbiology is Scary

Amelia S -

Hi guys! Welcome back to my blog, today I’m gonna be talking a bit about the actual viruses that cause the epidemics that my project is about. So, though this is mostly a history project, it is the history of science so brace yourself for some biology.

First up is Influenza! There are three main types of Flu Viruses (A, B, and C) and they are characterized into subtypes based on the version of their surface proteins. The two proteins used to classify them are Hemagglutinin (H) and Neuraminidase (N), so when I mention H1N1, I’m talking about subtype 1 Hemagglutinin and subtype 1 Neuraminidase. There are 18 different subtypes of H and 11 of N! Both proteins are super important to the pathogenicity of the virus, Hemagglutinin allows the flu virus to bind to the outside of host cells, allowing them to enter and replicate. N is also important and allows the newly replicated virus to break free from host cells so that they can spread and replicate further! Viruses aren’t alive and they can’t replicate without a host cell, so both proteins are absolutely vital to the flu making people sick. For super deadly pandemics like 1918, people often assume that there were certain mutations in H or N that allowed the virus to become so successful — that’s why scientists spent so long trying to figure out the specifics of the 1918 strain — to see what made it so fit!

SARS and COVID, on the other hand, are Coronaviruses (as I’m sure you know). CoVs are named after their crown shape (I think it’s a bit of a stretch, but whatever). Most coronaviruses cause mild respiratory illnesses — think the common cold — but during the 21st century there have been 3 major pandemic strains — SARS, MERS, and COVID-19. Interestingly, they only have one piece of genetic material — a really long strand of positive sense RNA. (Positive sense means it goes from 5′ -> 3′, Flu has 7 segments of negative sense RNA so 3′ -> 5′). Positive sense RNA viruses are cool because the RNA is used directly to translate into proteins, kind of like mRNA in a cell! Coronaviruses are a good bit more complicated than flu viruses — their genetic material is more than twice as big — so I’m not going to get more specific because we’d be here all day. Anyway, the point is that even though both types of viruses have similar effects on people, they are super different and super interesting, and my final product poster will have some more info on them — so check that out during presentation night!!

Thanks for listening to me ramble — science is so cool! I love biology!! more history next week though, I promise. Please comment if you didn’t understand anything, if I had to learn this for Capstone: Dynamics of Infectious Disease, so do you!

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    leah_b
    Since you don’t really agree with the name CoVs, what would you have named them?
    ryan_t
    Thank you for the explanation!
    Ms. Cooper
    Wow—this was such an engaging and informative post! I love how you broke down the differences between flu viruses and coronaviruses in a way that feels both approachable and scientifically rich. Your explanation of Hemagglutinin and Neuraminidase was super clear, and I especially liked how you connected that to the 1918 pandemic. The RNA comparison between flu and coronaviruses was a great touch too. I can tell how passionate you are about biology, and it really shines through in your writing. Can’t wait to see your final product on presentation night!

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