Download Ch. 8 Cell Membrane

DUBLIN HIGH SCHOOL AP BIOLOGY
CH. 8 STUDY GUIDE: CELL MEMBRANES
KEY TERMS
plasma(=cell) membrane
isotonic
fluid-mosaic model
crenation
phospholipid
plasmolysis
integral(=imbedded) protein
lysis
peripheral protein
facilitated diffusion
membrane channel
gated channel
transport protein
membrane pump
diffusion
active transport
passive transport
sodium-potassium pump
osmosis
endocytosis
selectively permeable
phagocytosis
osmotic concentration
pinocytosis
osmotic pressure(=potential)
pseudopodia
hypertonic
exocytosis
hypotonic
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WORDS ROOTS
amphi - = dual (amphipathic molecule: a molecule that has both a hydrophobic
and a hydrophilic region)
aqua - = water; - pori = a small opening (aquaporin: a transport protein in the
plasma membrane of a plant or animal cell that specifically facilitates the
diffusion of water across a membrane)
co - = together; trans - = across (cotransport: the coupling of the “downhill”
diffusion of one substance to the “uphill” transport of another against its own
concentration gradient)
electro- = electricity; - genic = producing (electrogenic pump: an ion transport
prottein generating voltage across a membrane)
endo - = inner; cyto - = cell (endocytosis: the movement of materials into a cell.
Cell-eating)
exo - = outer (exocytosis: the movement of materials out of a cell)
hyper - = exceeding; - tonus = tension (hypertonic: a solution with a higher
concentration of solutes)
hypo - = lower (hypotonic: a solution with a lower concentration of solutes)
iso - = same (isotonic: solutions with equal concetrations of solutes)
phago - = eat (phagocytosis: cell eating)
pino - = drink (pinocytosis: cell drinking)
plasm - = molded; - lyso = loosen (plasmolysis: a phenomenon in walled cells in
which the cytoplasm shrivels and the plasma membrane pulls away from the cell
wall when the cell loses water to a hypertonic environment)
QUESTIONS
1. Describe the processes of diffusion.
2. How does the random movement of molecules bring about an even distribution
of molecules throughout the system?
3. Describe the processes of osmosis.
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4. Using a diagram describe the fluid-mosaic model of the cell membrane.
Indicate the following; phospholipid molecules, hydrophobic and hydrophilic
ends, types of membrane proteins and glycoproteins. List substances to which
the membrane is relatively permeable and those substances to which it is
relatively impermeable.
5. Why is the term mosaic used to describe the fluid-mosaic model of the cell
membrane?
6. Define the terms hypotonic, hypertonic and isotonic and explain what would
happen to a cell if it were placed in each of these solutions.
7. Describe the role of membrane proteins in movement of materials through
membranes. Discuss integral proteins, and membrane pumps.
8. Distinguish between simple diffusion, facilitated diffusion, and active transport
and indicate the significance of these processes to the life of the cell.
9. Describe and diagram the sodium/potassium pump of the cell membrane.
10. Describe the processes of phagocytosis, pinocytosis, and exocytosis.
11. Describe how cells recognize each other, include a description of the role of
oligosaccharides, glycoproteins and glycolipids.
12. Differentiate between hypotonic, hypertonic and isotonic. Use the example of
red blood cells in pure water, in blood and in 5% salt water.
13. Why is it incorrect to say that a 1% salt solution is isotonic?
14. Justify the conclusion that differences in ion concentration between cells and
their surroundings indicates that cells regulate the passage of materials across
membranes.
15. In addition to the cell membrane, what membranous structures are included
in the endomembrane system?
16. In simple terms, using simple English, describe turgidity.
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