Question

complete each statement by selecting the correct word or phrase from each drop - down. 1. small, nonpolar molecules, like (click to select), pass directly through the phospholipid bilayer. 2. charged particles, like (click to select), can diffuse through the membrane if specific channel proteins are open. 3. some large, polar molecules, like (click to select) can cross the membrane via facilitated diffusion. 4. small, polar molecules, like (click to select), can slip through small gaps in the phospholipid bilayer.

Explanation:

1. Oxygen ($O_2$) is a small non - polar molecule that can pass directly through the phospholipid bilayer due to its non - polar nature and small size.
2. Sodium ions ($Na^+$) are charged particles that require specific channel proteins to diffuse through the membrane as the phospholipid bilayer is impermeable to charged species.
3. Glucose is a large polar molecule that crosses the membrane via facilitated diffusion with the help of carrier proteins.
4. Water ($H_2O$) is a small polar molecule that can slip through small gaps in the phospholipid bilayer, although its movement can also be facilitated by aquaporins.

Answer:

1. Oxygen
2. Sodium ions
3. Glucose
4. Water