CH 5: Cell Membranes

1
CH 5 Cell Membranes

• Practice Test

2
The movement of a substance toward an area of
lower concentration is called ________.

• diffusion
• osmosis
• active transport
• exocytosis

3
Which component in the cell membrane restricts
the passage of water-soluble substances?

• glycolipids
• protein
• oligosaccharides
• phospholipid

4
A membrane protein with two hydrophilic domains
will generally

• be an enzyme
• be an integral membrane protein
• be a peripheral membrane protein
• be involved with cell recognition

5
Which type of membrane protein will bind to a
signal molecule such as a hormone?

• adhesion
• passive transporter
• cell-to-cell communication
• receptor

6
Communication proteins permit ________.

• a cell to respond to extracellular signals
• cells to import signal molecules from the
  extracellular environment
• signaling between adjacent cells
• body cells to distinguish foreign cells

7
Which combination of conditions would promote the
most rapid diffusion across a cell membrane?

• large molecule, high temperature, large
  concentration gradient
• large molecule, low temperature, small
  concentration gradient
• small molecule, low temperature, small
  concentration gradient
• small molecule, high temperature, large
  concentration gradient

8
The term "selective permeability" describes the
characteristic of membranes that ________.

• restrict the passage of polar molecules
• provide an anchoring between adjacent cells
• allow membrane proteins to float freely within
  the membrane
• permit some molecules to cross the membrane while
  preventing others from crossing

9
In the absence of a specific carrier protein,
which type of molecule would be least likely to
cross the membrane?

• one that is large and polar
• one that is small and nonpolar
• one that is large and nonpolar
• one that is small and polar

10
Why is diffusion the method by which O2 and CO2
are transported across the cell membrane?

• it is faster than active transport
• it allows ions and molecules to accumulate at
  higher concentrations within the cell than in the
  surrounding environment
• the phospholipid bilayer is permeable to small,
  non-polar molecules
• protein components are needed in the cell
  membrane for diffusion to occur

11
Nerve cells contain an unusually high
concentration of potassium how are they able to
obtain concentrations of potassium greater than
those of the surrounding extracellular
environment?

• reverse diffusion
• reverse osmosis
• active transport
• facilitated diffusion

12
Which of the following is a characteristic of
active transport?

• solute movement across the membrane is toward the
  side with the higher concentration
• specific membrane proteins are required but no
  energy is needed
• only molecules with potential energy greater than
  ATP are transported
• it is a passive process

13
Proteins in membranes can provide all of the
following functions except ________.

• carriers for polar molecules
• insulation
• receptors
• enzymes

14
Imagine cells suspended in a fluid to which a
large amount of salt is suddenly added. If the
cell membrane were impermeable to the salt, the
cell would subsequently ________.

• die
• swell as it gains water osmotically
• shrink as it loses water osmotically
• experience no changes since it's impermeable,
  salt has no effect

15
Osmosis can be described as ________.

• movement of water from a region of high solute
  concentration to a region of low solute
  concentration
• movement of solute from an area of low solute
  concentration to an area of high solute
  concentration
• water molecules colliding with one another and
  the wall of a container
• movement of water across a membrane from an area
  of low solute concentration to an area of high
  solute concentration

16
Which graphic, A, B, or C, portrays what would
happen to cells in a hypertonic environment?

• A
• B
• C

17
The cell membrane ________.

• is selectively permeable
• has a bilayered phospholipid-protein structure
• defines the boundary of the cell
• all of the choices

18
The most abundant lipid in a cell membrane is
________.

• phospholipid
• steroids
• cholesterol
• triglycerides

19
When a plant cell is placed in a hypotonic
solution the plant cell will

• Lose water from its vacuole.
• Not be affected
• Take in water and potentially burst
• Take in water and expand up to its cell wall.

20
What feature of a vesicle would indicate an
endocytotic formation?

• there would not be any receptor proteins
• it would contain cytoplasmic fluid
• it would contain extracellular fluid
• integral proteins would be absent

21
Phagocytosis is one type of ________.

• active transport
• osmosis
• exocytosis
• endocytosis