A new blog post on the Sims 3 site explains in a little more detail the new building types that will come in the University Life expansion pack, as well as the PlantSims that will make their first appearance in the series since The Sims 2.
As is to be expected, the University Life expansion includes dorms, sorority houses, and fraternity houses. These are all essentially the same, except that dorms are co-ed and the latter two – obviously – are not. When you move your Sim into one of these buildings in the new University town, the game will automatically search fill the rest of the space with roommates. Another new building type is the apartments, which can also be used outside of the University town. Like in The Sims 2 Apartment Life, your Sims will pay weekly rent, the cost of which is relative to the lot's value.
PlantSims will also return from The Sims 2. These Sims are much closer to nature than others, and can talk to plants just like they would with a human. They're practically plant themselves, since they don't need to eat but do need to absorb water, for instance through swimming or absorbing puddles. New to The Sims 3, PlantSims have the ability to give other Sims Flower Kisses, which can cause the other Sim to become obsessed with them, or Poisonous Kisses that can make the other Sim sick. While you might meet a PlantSim wandering around your town after you've bought this expansion, it's pretty rare. But not to worry: you can apparently grow PlantSim babies by planting forbidden fruits.
The blog post ends with a few fun facts about the expansion, including that Nerd Sims will be able to play SimCity, which is pretty meta. The Sims 3 University Life launches on March 5th.