Question

Which of the following characteristics is shared by simple and facilitated diffusion of glucose?

1) Occurs down an electrochemical gradient
2) Is saturable
3) Requires metabolic energy
4) Is inhibited by the presence of galactose
5) Requires a Na⁺ gradient

Answer 1

Simple and facilitated diffusion of glucose do not require metabolic energy, but only facilitated diffusion requires a Na⁺ gradient to aid in the movement of glucose molecules.

Step-by-step explanation:

Both simple and facilitated diffusion of glucose share the characteristic of not requiring metabolic energy. This means that glucose molecules move across the cell membrane without the need for the cell to expend energy. Instead, glucose molecules move down their concentration gradient from an area of higher concentration to an area of lower concentration.

However, the characteristic of requiring a Na⁺ gradient is specific to facilitated diffusion, not simple diffusion. Na⁺, or sodium ions, can assist in the movement of glucose molecules across the cell membrane through facilitated diffusion.

So, in summary, both simple and facilitated diffusion of glucose do not require metabolic energy, but only facilitated diffusion requires a Na⁺ gradient to aid in the movement of glucose molecules.