Plasmids

For my school's Projects Day 2009, two friends, Wang Fan and Philmann(click here to view his blog) and I will possibly be doing a projects on plasmids. Plasmids occur naturally as double strands of DNA that are coiled up in the topographic shape of a torus(simulate this by twisting an adapter tightly and then plugging it into itself). Plasmids and viruses have many things in common.

1. Both act independantly from their host.
2. They are not living things.
3. They are packets of DNA without any organelles.

However, they are also very different.

1. Viruses destroy the host and propagate, whereas plasmids travel within the host and only destroy the host when the plasmid has been replicated and passed on to one of the host's daughter cells. Some plasmids don't destroy the host at all.
2. Viruses' method of propagation involves rupturing the cell and destroying it after an incubation period when the virus replicates while plasmids act as "upgrades", with different plasmids acting in different ways, e.g. providing resistance to antibiotics, increasing rate of reproduction.
3. Plasmids also only replicate when they are about to passed on.

Please correct me if any of my data is wrong. I will write more as my project progresses.

By the way, if you see any "Ah Phui"s on any other blogs, they refer to Philmann.