Cell Membrane Unit Test
Which of the following factors would tend to increase membrane fluidity?
a greater proportion of unsaturated phospholipids
Which means of particle transport requires input to energy from the cell?
active transport
Which of these processes can move a solute against its concentration gradient?
active transport
Diffusion is the movement of molecules from
an area of high concentration to an area of low concentration
The ___________ regulates which substances enter and leave a cell
cell membrane
Which of the following structures serves as the cell's boundary from its environment
cell membrane
Once _________ is reached, roughly equal numbers of molecules move in either direction across a semipermeable membrane, and there is no further change in concentration on either side of the membrane
equilibrium
What membrane-surface molecules are though to be most important as cells recognize each other
glycoproteins
The interior of the phospholipid bilayer is
hydrophobic
Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
it exhibits a specificity for a particular type of molecule
Which of the following statements is correct about diffusion?
it is a passive process in which molecules move from a region of higher concentration to lower concentration
When the concentration of molecules on both sides of a membrane is the same, the molecules will
move across the membrane in both directions
the diffusion of water across a selectively permeable membrane is called
osmosis
White blood cells engulf bacteria through what process?
phagocytosis
The cell membrane contains channels and pumps that help move material from one side to another. What are these channels and pumps made of?
proteins
Which of the following is a function of the cell membrane>
regulates which materials enter and leave the cell
A red blood cell placed in pure water will
swell
Diffusion occurs because
the concentration of a solution is never the same throughout a solution
Of the following, which is the most important role of exocytosis?
to release substances from the cell
Unlike the cell membrane, the cell wall is
usually made of tough fibers
an animal cell that is surrounded by fresh water will burst because the osmotic pressure causes
water to move into a cell