Your job is to assess whether what we know about neurons is suuficent to say whether or not a model of them could be the computing element in a model of the brain. To focus your efforts you may want to take a pro or con position.
A successful essay would, as a minimum, touch upon 1) the structure of a neuron 2) the number of neurons and synapses 3) a basic architecture of how the neural circuits would be used and 4) timing constraints.
A huge number of facts about neurons is available on the Web.