Category Archives: Biol 105 Assignments

Have Fun Storming the Castle!

One of the things that I find most interesting about viruses is the diversity in their replication cycles.  It seems that for every barrier that viruses encounter during replication it is overcome in a myriad of ways.

Imagine you are a warrior invading a castle.  How many different ways can you penetrate the defenses, cross the moat, get through the walls, and then access and use all the stuff inside for your own benefit?  Will you knock down the gate?  Will you sneak through the windows?  Catapult yourself over the wall?

A Virus must enter a host cell, take over the machinery to make lots of copies of itself, then get out and transmit to the next host.  While the viral replication cycle of all viruses follows the same general patterns, the subtle differences are fascinating.  Its like an evolutionary brainstorm that resulted in thousands of different ways to solve the same basic problem.

Ive asked my Biol 105 class to read Ch 19 of Campbell’s Biology and post a comment about an interesting thing about viruses that caught their attention.  DId you learn something new and surprising?  What is it about it that is interesting to you?


Viruses: Dead or Alive

An ongoing question in virology is whether viruses are to be considered living creatures.  Its easy to tell that a groundhog is alive but a book is not.  But what properties does a groundhog have that a book does not?  We can look up basic properties of living things in a biology textbook, and yet it remains difficult to define life in a simple sentence.

I would argue that a virus is not alive. Viruses are completely dependent on host cells to replicate.  That said, in absence of the host cell the virus clearly lacks most of the properties of a living thing.  (Does stealing those properties from a living thing count towards being alive?)  Life seems to emerge from a collection of parts where the whole is greater  than the sum of the parts.  This emergent property, life, is present in animals, plants, bacteria etc, but in a virus infected cell, that property remains a part of the cell, not the virus.

Alive or not, viruses are an integral part of biology.  They help us understand life and they certainly have an effect on living things.