Chapter 8
A cell placed in a high salt solution would swell because of osmosis.
F
Cell-surface markers face the inside of the cell.
F
Exocytosis is a process that uses vesicles to capture substances and bring them into a cell.
F
Osmosis is the diffusion of starch molecules through a selectively permeable membrane.
F
The cell membrane is made up of a double layer called the DNA bilayer.
F
The nonpolar tails of a phospholipid are attracted to water.
F
When the solute concentration outside a cell is equal to the solute concentration inside the cell, the cell's environment is hypotonic.
F
Refer to the illustration above. What happens when the structure labeled A binds to the structure labeled B?
Information is sent into the cell.
What change takes place in the cell membrane if a signal molecule causes a transport protein to open?
Permeability change
A concentration gradient exists when one area has a higher concentration of a substance than another area does.
T
Receptor proteins may cause the formation of a second messenger molecule inside the cell.
T
The movement down a concentration gradient is called diffusion.
T
Which of the following statements about an isotonic solution and a cell is correct?
The solution has the same solute concentration that the cytoplasm does.
Both active transport and facilitated diffusion involve
carrier proteins.
Proteins in the cell membrane that identify the cell are called
cell surface marker
Refer to the illustration above. The structure labeled C is a(n)
cell-surface marker.
Proteins that serve as tunnels for specific substances through the lipid bilayer are
channel proteins.
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
exocytosis
Removing materials from a cell in vesicles is called
exocytosis
Sugar molecules cross the cell membrane by
facilitated diffusion.
How many potassium ions does the sodium-potassium pump move into a cell if it moves six sodium ions out of the cell?
four
Diffusion is the movement of a substance
from an area of high concentration to an area of lower concentration.
The sodium-potassium pump
is a carrier protein.
Refer to the illustration above. The structure labeled A is composed of
lipids
Phospholipids are molecules that have
one polar phosphate head and two non polar fatty acid tails
The diffusion of water into or out of a cell is called
osmosis
Ions move through ion channels by
passive transport
Osmosis is a type of
passive transport.
Which type of molecule forms the cell membrane?
phospholipid
The sodium-potassium pump usually pumps
potassium ions into the cell
Refer to the illustration above. The structure labeled B in the diagram is an example of a(n)
receptor protein.
Signal molecules bind to
receptor proteins
Which of the following transmit information into a cell by binding to signal molecules?
receptor proteins
The interior of the lipid bilayer of a cell membrane forms a nonpolar zone that
repels ions and most polar molecules
Unlike passive transport, active transport
requires energy
Which of the following descriptions of hormones is correct?
signal molecules distributed throughout the body
Which of the following is a form of active transport?
sodium-potassium pump
How does water pass through the cell membrane?
through channel proteins just for water
Refer to the illustration above. The structure labeled D is a(n)
transport protein
Refer to the illustration above. The process shown is called
diffusion
The dispersal of ink in a beaker of water is an example of
diffusion
Which of the following does not require energy?
diffusion
cell membrane : cell ::
door : house
Proteins and polysaccharides that are too large to move into a cell through diffusion or active transport move in by
endocytosis
As a result of diffusion, the concentration of many types of substances
eventually becomes balanced on both sides of a membrane.