BIOL 1201 Louisiana State University | Exam 2 Practice
Questions And Answers | 2025-2026 Updated Tests | A+
Grade
1. Which best describes a biological membrane?
a. two layers of phospholipids with proteins embedded between the two layers
b. a mixture of covalently linked phospholipids and proteins that determines which solutes can
cross the membrane and which cannot
c. two layers of phospholipids with proteins either spanning the layers or on the surface of the
layers
d. a fluid structure in which phospholipids and proteins move freely between sides of the
membrane
e. two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with
each layer covered on the outside with proteins
2. Which molecule will diffuse most quickly across a lipid bilayer membrane?
a. H2O
b. O2
c. H2PO4–
d. glucose
e. Na+
3. A correct distinction between facilitated diffusion and active transport is that
a. active transport requires conformational changes in the transport protein associated with
the transport process, and facilitated diffusion does not.
b. active transport requires an integral membrane protein to carry out the transport, and
facilitated diffusion does not.
c. facilitated diffusion requires a protein-lined pore in the membrane, and active transport
does not.
d. facilitated diffusion depends on an existing energy gradient acting on the transported
substance, while active transport makes such a gradient.
e. facilitated diffusion requires cellular energy (often from ATP hydrolysis), but active transport
does not.
4. At a cocktail party with people moving around a large room, the doors to the room are like
_____.
, a. energy
b. membrane proteins
c. DNA
d. organelles
e. none of the above
5. You are studying a pump protein in the lab. What should you order to make sure that the pump
will operate?
a. salt
b. glucose
c. DNA
d. pure water
e. ATP
6. How do membrane phospholipids interact with water?
a. Phospholipid do not interact with water because they are lipids, and this are completely
hydrophobic
b. They have hydrophilic tails that face outward and are exposed to water and hydrophobic
heads that face the center of the membrane and are shielded from water
c. The polar heads have no affinity for water and the nonpolar tails have an affinity for water
d. The polar heads interact with water; the nonpolar tails do not.
7. Which of the following factors would tend to increase membrane fluidity?
a. a greater proportion of unsaturated phospholipids
b. a greater proportion of saturated phospholipids
c. a lower temperature
d. a relatively high protein content in the membrane
8. Based on our model of the membrane, which statement would lose points on an exam?
a. Glycoproteins tend to have oligosaccharides on their outward-facing side.
b. Transmembrane proteins often bind with cytoplasmic proteins, but not with extracellular
molecules.
c. The combinations of phospholipids in the two faces of the membrane often differ.
d. Phospholipids tend to move faster laterally along the membrane than do the proteins.
e. Some transmembrane proteins function as active transport systems.
9. What is the function of cholesterol in membrane structure?
a. stabilization of the phospholipids
Questions And Answers | 2025-2026 Updated Tests | A+
Grade
1. Which best describes a biological membrane?
a. two layers of phospholipids with proteins embedded between the two layers
b. a mixture of covalently linked phospholipids and proteins that determines which solutes can
cross the membrane and which cannot
c. two layers of phospholipids with proteins either spanning the layers or on the surface of the
layers
d. a fluid structure in which phospholipids and proteins move freely between sides of the
membrane
e. two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with
each layer covered on the outside with proteins
2. Which molecule will diffuse most quickly across a lipid bilayer membrane?
a. H2O
b. O2
c. H2PO4–
d. glucose
e. Na+
3. A correct distinction between facilitated diffusion and active transport is that
a. active transport requires conformational changes in the transport protein associated with
the transport process, and facilitated diffusion does not.
b. active transport requires an integral membrane protein to carry out the transport, and
facilitated diffusion does not.
c. facilitated diffusion requires a protein-lined pore in the membrane, and active transport
does not.
d. facilitated diffusion depends on an existing energy gradient acting on the transported
substance, while active transport makes such a gradient.
e. facilitated diffusion requires cellular energy (often from ATP hydrolysis), but active transport
does not.
4. At a cocktail party with people moving around a large room, the doors to the room are like
_____.
, a. energy
b. membrane proteins
c. DNA
d. organelles
e. none of the above
5. You are studying a pump protein in the lab. What should you order to make sure that the pump
will operate?
a. salt
b. glucose
c. DNA
d. pure water
e. ATP
6. How do membrane phospholipids interact with water?
a. Phospholipid do not interact with water because they are lipids, and this are completely
hydrophobic
b. They have hydrophilic tails that face outward and are exposed to water and hydrophobic
heads that face the center of the membrane and are shielded from water
c. The polar heads have no affinity for water and the nonpolar tails have an affinity for water
d. The polar heads interact with water; the nonpolar tails do not.
7. Which of the following factors would tend to increase membrane fluidity?
a. a greater proportion of unsaturated phospholipids
b. a greater proportion of saturated phospholipids
c. a lower temperature
d. a relatively high protein content in the membrane
8. Based on our model of the membrane, which statement would lose points on an exam?
a. Glycoproteins tend to have oligosaccharides on their outward-facing side.
b. Transmembrane proteins often bind with cytoplasmic proteins, but not with extracellular
molecules.
c. The combinations of phospholipids in the two faces of the membrane often differ.
d. Phospholipids tend to move faster laterally along the membrane than do the proteins.
e. Some transmembrane proteins function as active transport systems.
9. What is the function of cholesterol in membrane structure?
a. stabilization of the phospholipids
