In plant cells, the concentration of ions and other materials is significantly higher in the vacuole than in the cytoplasm. This accumulation against the concentration gradient is facilitated by which of the following?

Options:

• A: Passive diffusion through the tonoplast
• B: Simple osmosis across the cell wall
• C: Facilitated diffusion via aquaporins
• D: Active transport facilitated by proteins in the tonoplast

Related Practice Questions:

• Let $S_1$ and $S_2$ be two disjoint, non-empty convex sets in $\mathbb{R}^n$. Under which of the following conditions is there guaranteed to exist a hyperplane that strictly separates $S_1$ and $S_2$?
• Let the primal linear programming problem be: Maximize $Z = c^T x$ subject to $Ax \le b, x \ge 0$. If this primal problem has an unbounded optimal objective value, then which of the following statements is always true regarding its dual problem?
• Let $S = \{(x, y) \in \mathbb{R}^2 \mid x^2 + y^2 \le 9\}$ be a convex set in $\mathbb{R}^2$. The set of all extreme points of $S$ is given by:
• In a linear programming problem with $3$ independent equality constraints and $5$ variables (including slack/surplus variables), what is the maximum possible number of basic solutions?