Chapter 20, Problem 56P

For each of the processes below, tell whether it is based on facilitated diffusion, primary active transport, secondary active transport, or a cell receptor:

(a) LDL movement into the cell

(b) Movement of glucose into the cell by glucose permease

(c) Movement of lactose into the cell by galactoside permease

(d) Exchange of ${\text{Na}}^{+}$ and ${\text{K}}^{+}$ ions across a membrane by the ${\text{Na}}^{+}/{\text{K}}^{+}$ pump