For the essay i'm pretty certain that it will be based on Biomolecules ( ATP, water, ions, proteins, enzymes, carbohydrates) since this synoptic area hasn't come up for a while.
Possibly a genetics one (How parents produce offspring that differ from each other), and least likely transport/movements/energy.
These are just a logical assumption on the essays that have and haven't come up. Knowing aqa they will probably end up dropping a "dry" essay in like the homeostasis one or negative feedback. What thoughts have you guys got on this and do you agree.