Membranes and Transport (Chapter 5) Test Questions with Verified Answers Rated A
1. phospholipid bi- architecture of membranes; two layers of phospholipids
layer
2. amphipathic a molecule that has both a hydrophilic region and a hydrophobic region.
3. fluid-mosaic the currently accepted model of cell membrane structure, which envisions the
model membrane as a mosaic of individually inserted protein molecules drifting laterally
in a fluid bilayer of phospholipids; proposed by Singer and Nicolson
4. leaflet one half of the phospholipid bilayer
5. transmembrane Integral proteins that span the membrane.
proteins
6. lipid-anchored integral proteins that covalently attach to a membrane lipid molecule
proteins
7. extrinsic proteins that associate with membrane in a non-covalent way
1/8
, 8. selective perme- a property of a plasma membrane that allows some substances to cross more easily
ability than others
9. diffusion movement of molecules from an area of higher concentration to an area of lower
concentration
10. passive transport the movement of substances across a cell membrane without the use of energy by
the cell; molecules move from high to low concentration (down their concentration
gradient)
11. active transport the movement of materials through a cell membrane using energy; molecules
move from low to high concentration (against concentration gradient)
12. simple diffusion
2/8
1. phospholipid bi- architecture of membranes; two layers of phospholipids
layer
2. amphipathic a molecule that has both a hydrophilic region and a hydrophobic region.
3. fluid-mosaic the currently accepted model of cell membrane structure, which envisions the
model membrane as a mosaic of individually inserted protein molecules drifting laterally
in a fluid bilayer of phospholipids; proposed by Singer and Nicolson
4. leaflet one half of the phospholipid bilayer
5. transmembrane Integral proteins that span the membrane.
proteins
6. lipid-anchored integral proteins that covalently attach to a membrane lipid molecule
proteins
7. extrinsic proteins that associate with membrane in a non-covalent way
1/8
, 8. selective perme- a property of a plasma membrane that allows some substances to cross more easily
ability than others
9. diffusion movement of molecules from an area of higher concentration to an area of lower
concentration
10. passive transport the movement of substances across a cell membrane without the use of energy by
the cell; molecules move from high to low concentration (down their concentration
gradient)
11. active transport the movement of materials through a cell membrane using energy; molecules
move from low to high concentration (against concentration gradient)
12. simple diffusion
2/8
