Which type of membrane protein is involved in both active transport and facilitated transport? A) carrier B) cytoskeletal (C) structural (D) targeted (E) enzymatic

A carrier protein is your go-to here! These versatile membrane proteins play a crucial role in both active transport, where they move substances against their concentration gradient using energy (think of it as a 24/7 delivery service), and facilitated transport, where they help molecules like glucose or ions cross the membrane down their concentration gradient without needing energy. Did you know that carrier proteins are often highly specific? They have binding sites designed just for certain molecules, which means they can efficiently pick up and deliver their "cargo" across the cell membrane. Talk about VIP treatment for nutrients and ions!