Multiple choice

A small molecule diffuses from the cytosol of one cell to the mitochondrial matrix of the neighbouring cell. How many membranes does it traverse?

  1. Two

  2. Three

  3. Four

  4. Five

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

To go from cytosol to mitochondrial matrix of a neighboring cell: exit first cell (plasma membrane), enter second cell (plasma membrane), cross outer mitochondrial membrane, cross inner mitochondrial membrane. Total: 4 membranes.