There is no defined limit on the capacity of the brain. The brain's capacity cannot be measured as it is not subject to a defined "space" where the memory is kept, and it is not such that each neuron is responsible for a single memory. The brain has complex mechanisms of memory storage, that even improve if trained.
Enzymes are biological catalysts that speed up reactions
Remember the definition of Osmosis; Water travels through a semipermeable membrane to an area of higher to lower concentration. Since the concentration of a solute is higher outside, we can make the assumption that water concentration is lower, and so the cell is going to release water to balance out and equalize the solution and it's surroundings.
