Question

1.If glucose is ALWAYS present at higher concentrations outside the cell than inside the cell, explain why it needs its own transporter protein to get into

Answer 1

Cell membrane is usually made up of phospholipids which have hydrophilic heads and hydrophobic tails.these heads form the outer and inner surface of membrane and tails form the middle of membrane. glucose is usually a polar molecule and hydrophilic..so when glucose tends to go down the concentration gradient the head end accepts it as it is hydrophilic but the tail end repels it(hydrophobic).that is the reason why glucose needs transporter protein with hydrophilic layer inside that allows glucose molecule to pass.