Download Name Date____________ Block ___ Movement of Materials

Name ____________________
Date____________ Block ___
Movement of Materials Through the Cell Membrane
In this section you learned about processes by which materials enter and leave the
cell. These processes are diffusion, osmosis, facilitated diffusion and active
transport.
Diffusion is the process by which molecules of a substance move from areas of
higher concentration to areas of lower concentration. Whether a substance will diffuse
across a membrane depends on the permeability of the membrane to that substance as
well as the concentration of the substance on either side of the membrane.
Osmosis is the diffusion of water molecules through a selectively permeable
membrane.
Facilitated diffusion is the process in which carrier proteins help transport certain
molecules across the cell membrane. This allows materials to be transported across the
membrane quickly and selectively. But it can work only if the correct kind of concentration
difference exists across the membrane.
Active transport enables materials to move across a cell membrane against a
concentration difference. Active transport requires energy. There are two types of active
transport. In one type, transport macromolecules pump materials across the membrane.
In the other type, movement of the cell membrane take in or remove relatively large
amounts of material through phagocytosis, pinocytosis, exocytosis, or the use of a
contractile vacuole.
Word Bank:
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Diffusion
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Phagocytosis
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Osmosis
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Pinocytosis
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Facilitated diffusion
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Exocytosis
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Active Transport
Identifying Processes: Using the Main Ideas
Name the process involved in moving molecules across the cell membrane in each of the
following cases. When appropriate, use a more specific term. (For example, “cat” would
be a better answer than “animal.”)
1. Fresh water moves into a single-celled organism. ________________________
Inside cell = 94% water
Outside cell =
100% water
2. Pockets of the cell membrane fill with water and pinch off to become vacuoles
inside the cell. _______________________________________
Water
3. Oxygen molecules (O2) move from the lungs into the bloodstream.
________________________________
100 units of
O2
40 units of O2
4.
An amoeba engulfs a large particle of food. ____________________________
5. Carrier proteins transport glucose into a muscle cell. ________________________
0.3% glucose
outside of cell
0.05%
glucose
inside of
the cell
6. Sodium ions (Na+) are pumped out of a red blood cell. _______________________
155 units
Na+ outside
of cell
19 units of
Na+ inside of
cell