Who is Jenna Smith from Going Bovine and what is their importance?

Jenna Smith is Cameron's twin sister. She is everything that Cameron isn't: smart, popular, and able to deal with the realities of life. Jenna loves Cameron, but is tired of being embarrassed by his druggie behavior at school. Jenna is determined to ignore the dysfunction that is going on at home and has thrown herself into being perfect and popular at school. Jenna is deeply effected by Cameron's illness and sits by his bedside at the hospital. She shows up on his quest and the two are able to make peace before Cameron's time runs out.