CELLULAR ORGANIZATION
1
Movement Across Cell Membrane
1. Following receptor mediated endocytosis, the clathrin and receptors will be recycled back to
the cell membrane. (T/F)
2. Clathrin is used in receptor mediated endocytosis to dislodge the material bound to the
receptor so that the once-bound material can be destroyed. (T/F)
3. If a cell is placed into an hypertonic media, it will swell due to __ and possibly undergo lysis.
a. facilitated diffusion
b. active transport
c. diffusion
d. osmosis
4. Oxygen and carbon dioxide can move into or out of cells by __ because they are nonpolar.
a. facilitated diffusion
b. active transport
c. diffusion
d. osmosis
5. A gated channel is a special form of __ in which movement takes place with the gradient but
only when some signal removes the gate from the channel.
a. facilitated diffusion
b. active transport
c. diffusion
d. osmosis
6. Large, insoluble structures (e.g., a mitochondrion released from a dead cell) could enter into
another cell to be degraded by
a. active transport
b. bulk flow transport
c. pinocytosis
d. phagocytosis
7. Which of the following is NOT true of receptor mediated endocytosis?
a. it is a form of pinocytosis
b. bound receptors accumulate in clathrin coated pits
c. bound receptors are brought into the cells in membrane bound endosomes
d. both the receptor and what is bound to the receptor are destroyed when the
internalized vesicle fuses with lysosomes.
8. During osmosis,
a. ions are transported across a cell membrane by active transport.
b. ions are transported across a cell membrane by facilitated diffusion.
c. water is drawn across a cell membrane due to a higher concentration of solutes on
one side than the other.
d. water is drawn across a membrane in order to repolarize the membrane
CELLULAR ORGANIZATION
2
Short Answer
The sketch below shows two Na/K pump units embedded in the cell membrane. Attach labels to
this drawing to show when Na+ is attached and released and when K+ is attached and released.
Why is this an active transport process? Briefly describe three important physiological processes
that rely on the action of this pump.