Multiple choice

Which cellular structure controls what enters and exits the cell?

  1. Mitochondrion

  2. Cell wall

  3. Nucleus

  4. Cell membrane

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cell membrane (or plasma membrane) is selectively permeable, meaning it regulates the passage of substances into and out of the cell. The cell wall provides structural support but is fully permeable, while the nucleus and mitochondria have different metabolic and genetic functions.