Question 1
The phospholipid molecules of most membranes have
◦ a hydrophobic head and a hydrophilic tail.
◦ a hydrophobic head and a hydrophobic tail.
◦ a hydrophobic head and two hydrophobic tails.
◦ a hydrophilic head and two hydrophobic tails.
◦ two hydrophobic tails.
Question 2
The proteins of the cell membrane are
◦ enzymes.
◦ channels through the membrane.
◦ transporters that move substances across the membrane.
◦ receptors.
◦ all of these.