Chapter 3 Cell Membrane Structure & Function
Cell (plasma) membrane - phospholipid bilayer; selectively permeable membrane.
Fluid mosaic model - many different ________________ floating in the phospholipid bilayer.
Cell walls - stiff coatings around outside of cell membrane of bacteria, plants, fungi, and some protists.
Plasmodesmata - openings in the walls of adjacent _______________ cells.
I. Membrane Components
1. Cholesterol in the membrane stabilize the membrane.
2. Integral proteins - ____________ membrane.
3 Peripheral proteins - one _____________ or the other of the membrane.
4. Transport proteins - have _______________ through which substances can pass
5. Receptor proteins - receive a signal from a chemical messenger (________________).
6. Recognition proteins - distinguish self from non-self; part of _______________ system.
II. Transport Across Membrane
1. Selectively permeable - only lets _______________ things in, but not others.
2. Hydrophobic molecules (hydrocarbons, CO2, O2) and ____________ uncharged molecules (water,
ethanol) can pass easily through the membrane.
3. Large uncharged molecules (glucose and other _____________) and ions (Na+, Cl-, H+) generally
cannot pass through the membrane; they must be taken in through a transport protein.
4. Simple diffusion - a random mixing of ion / molecules; goes from ______________ to low concentration.
The rate of diffusion depends on:
A . Steepness of the concentration gradient; more difference, the ______________ the diffusion.
B. ________________ temperature faster diffusion.
C. Size of thing diffusing; _______________ things diffuse faster.
D. Surface area; _______________ area to diffuse across, the better.
E Diffusion distance; the shorter the distance, the ________________.
5. Facilitated diffusion - facilitated by transport proteins; still diffuses from high to _______________.
6. Osmosis - selectively permeable membrane; _______________ moves to higher ion concentration.
7. Active transport - uses ______________ (ATP) to go from low to high concentration of ion.
In cystic fibrosis the cells of the respiratory system have a bad Na __________________ transporter gene.
8. Exocytosis - pushes things ____________ of the cell.
9. Endocytosis - brings things _______________ the cell.
10. Receptor-mediated endocytosis - things come ________ the cell because there is a receptor on the
outside saying over here.
11. Phagocytosis - cell _________________.
12. Pinocytosis - cell _______________.
III. Types of Solutions
1. Isotonic - concentration in Red Blood Cell = concentration in beaker
- concentration in cell = concentration outside of cell
2. Hypotonic - less ___________;
- concentration in Red Blood Cell > concentration in beaker
- concentration in cell > concentration outside
- the solution is hypotonic to the Red Blood Cell
Hemolysis - RBCs ______________
3. Hypertonic - _____________ salt
- concentration in Red Blood Cell < concentration in beaker
- concentration in cell < concentration outside
- the solution is hypertonic to the Red Blood Cell
Crenation - RBCs _______________
Last updated: 1-24-07.
Cell (plasma) membrane - phospholipid bilayer; selectively permeable membrane.
Fluid mosaic model - many different ________________ floating in the phospholipid bilayer.
Cell walls - stiff coatings around outside of cell membrane of bacteria, plants, fungi, and some protists.
Plasmodesmata - openings in the walls of adjacent _______________ cells.
I. Membrane Components
1. Cholesterol in the membrane stabilize the membrane.
2. Integral proteins - ____________ membrane.
3 Peripheral proteins - one _____________ or the other of the membrane.
4. Transport proteins - have _______________ through which substances can pass
5. Receptor proteins - receive a signal from a chemical messenger (________________).
6. Recognition proteins - distinguish self from non-self; part of _______________ system.
II. Transport Across Membrane
1. Selectively permeable - only lets _______________ things in, but not others.
2. Hydrophobic molecules (hydrocarbons, CO2, O2) and ____________ uncharged molecules (water,
ethanol) can pass easily through the membrane.
3. Large uncharged molecules (glucose and other _____________) and ions (Na+, Cl-, H+) generally
cannot pass through the membrane; they must be taken in through a transport protein.
4. Simple diffusion - a random mixing of ion / molecules; goes from ______________ to low concentration.
The rate of diffusion depends on:
A . Steepness of the concentration gradient; more difference, the ______________ the diffusion.
B. ________________ temperature faster diffusion.
C. Size of thing diffusing; _______________ things diffuse faster.
D. Surface area; _______________ area to diffuse across, the better.
E Diffusion distance; the shorter the distance, the ________________.
5. Facilitated diffusion - facilitated by transport proteins; still diffuses from high to _______________.
6. Osmosis - selectively permeable membrane; _______________ moves to higher ion concentration.
7. Active transport - uses ______________ (ATP) to go from low to high concentration of ion.
In cystic fibrosis the cells of the respiratory system have a bad Na __________________ transporter gene.
8. Exocytosis - pushes things ____________ of the cell.
9. Endocytosis - brings things _______________ the cell.
10. Receptor-mediated endocytosis - things come ________ the cell because there is a receptor on the
outside saying over here.
11. Phagocytosis - cell _________________.
12. Pinocytosis - cell _______________.
III. Types of Solutions
1. Isotonic - concentration in Red Blood Cell = concentration in beaker
- concentration in cell = concentration outside of cell
2. Hypotonic - less ___________;
- concentration in Red Blood Cell > concentration in beaker
- concentration in cell > concentration outside
- the solution is hypotonic to the Red Blood Cell
Hemolysis - RBCs ______________
3. Hypertonic - _____________ salt
- concentration in Red Blood Cell < concentration in beaker
- concentration in cell < concentration outside
- the solution is hypertonic to the Red Blood Cell
Crenation - RBCs _______________
Last updated: 1-24-07.
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