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BIOLOGY 93 UCI MIDTERM 1 KEY TERMS 2025
QUESTIONS AND ANSWERS.
1. Peripheral Proteins - correct answer - Are not embedded in the lipid
bilayer at all; they are appendages loosely bound to the surface of the
membrane often to exposed parts of integral protein
2. Transmembrane Proteins - correct answer - Transmembrane protein
span the entire phospholipid bilayer.
3. Glycolipids - correct answer - Membrane lipids that may have
carbohydrate chains in the exoplasmic domain
4. Glycoproteins - correct answer - Membrane carbohydrates that are
covalently bonded to proteins.
5. Transport Proteins - correct answer - membrane proteins that help move
specific ions, and a variety of polar molecule across a semi-permeable
cell membrane
6. FRAP - correct answer - Fluorescent
Recovery
After
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Photobleaching
Measures the fluidity of a membrane by shooting a laser that bleaches
fluorescent markers on the membrane and measures the time of
fluorescence
7. Diffusion coefficient - correct answer - Typically, a compound's diffusion
coefficient is ~10,000× as great in air as in water. Carbon dioxide in air
has a diffusion coefficient of 16 mm2/s, and in water its diffusion
coefficient is 0.0016 mm2/s. Diffusivity has an SI unit of m2/s (length2 /
time).
A multiplier relating diffusion flux to the concentration gradient
8. Diffusion - correct answer - The movement of particles of any substance
so that they spread out in available space. In the absence of other
forces, a substance will diffuse from where it is more concentrated.ed to
where it is less concentrated.
9. Concentration Gradient - correct answer - Any substance will diffuse
down its concentration gradient, the region along which the density of a
chemical substance increases or decreases.
10. Passive Transport - correct answer - The diffusion of a substance
across a biological membrane is called passive transport because the
cell does not have to expend energy to make this happen.
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11. Osmosis - correct answer - The diffusion of free water across a
selectively permeable membrane.
12. Tonicity - correct answer - The ability of a surrounding solution to
cause a cell to gain or lose water
13. Hypotonic - correct answer - Having a lower concentration of solute
than another solution (relative to the cell).
14. Isotonic - correct answer - Having the same solute concentration as
another solution (relative to the cell).
15. Hypertonic - correct answer - Having a higher concentration of solute
than another solution (relative to the cell).
16. Facilitated diffusion - correct answer - The diffusion of molecules
across a membrane through transport proteins
17. Channel Proteins - correct answer - have a hydrophilic channel that
certain molecules or ions can use as a tunnel
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18. Ion Channels - correct answer - channel proteins that transport ions
19. Gated Channels - correct answer - a transmembrane protein channel
that opens or closes in response to a particular stimulus (usually
electrical).
20. Carrier proteins - correct answer - bind to molecules and change
shape to shuttle them across the membrane
21. Active Transport - correct answer - The movement of substances
across the cell membrane that requires the cell to use energy. Pumping
a solute against its electrochemical gradient requires energy.
22. Sodium-Potassium Pump - correct answer - 2 K+ ions in, 3 Na+ ions
out. A form of active transport that requires energy in the form of ATP.
Also, this allows a cell to maintain a negative membrane potential. The
Na-K pump generates voltage across the membrane and is therefore
classified as an electrogenic pump.
23. Membrane potential - correct answer - The voltage across a cell's
plasma membrane.
BIOLOGY 93 UCI MIDTERM 1 KEY TERMS 2025
QUESTIONS AND ANSWERS.
1. Peripheral Proteins - correct answer - Are not embedded in the lipid
bilayer at all; they are appendages loosely bound to the surface of the
membrane often to exposed parts of integral protein
2. Transmembrane Proteins - correct answer - Transmembrane protein
span the entire phospholipid bilayer.
3. Glycolipids - correct answer - Membrane lipids that may have
carbohydrate chains in the exoplasmic domain
4. Glycoproteins - correct answer - Membrane carbohydrates that are
covalently bonded to proteins.
5. Transport Proteins - correct answer - membrane proteins that help move
specific ions, and a variety of polar molecule across a semi-permeable
cell membrane
6. FRAP - correct answer - Fluorescent
Recovery
After
, Page |2
Photobleaching
Measures the fluidity of a membrane by shooting a laser that bleaches
fluorescent markers on the membrane and measures the time of
fluorescence
7. Diffusion coefficient - correct answer - Typically, a compound's diffusion
coefficient is ~10,000× as great in air as in water. Carbon dioxide in air
has a diffusion coefficient of 16 mm2/s, and in water its diffusion
coefficient is 0.0016 mm2/s. Diffusivity has an SI unit of m2/s (length2 /
time).
A multiplier relating diffusion flux to the concentration gradient
8. Diffusion - correct answer - The movement of particles of any substance
so that they spread out in available space. In the absence of other
forces, a substance will diffuse from where it is more concentrated.ed to
where it is less concentrated.
9. Concentration Gradient - correct answer - Any substance will diffuse
down its concentration gradient, the region along which the density of a
chemical substance increases or decreases.
10. Passive Transport - correct answer - The diffusion of a substance
across a biological membrane is called passive transport because the
cell does not have to expend energy to make this happen.
, Page |3
11. Osmosis - correct answer - The diffusion of free water across a
selectively permeable membrane.
12. Tonicity - correct answer - The ability of a surrounding solution to
cause a cell to gain or lose water
13. Hypotonic - correct answer - Having a lower concentration of solute
than another solution (relative to the cell).
14. Isotonic - correct answer - Having the same solute concentration as
another solution (relative to the cell).
15. Hypertonic - correct answer - Having a higher concentration of solute
than another solution (relative to the cell).
16. Facilitated diffusion - correct answer - The diffusion of molecules
across a membrane through transport proteins
17. Channel Proteins - correct answer - have a hydrophilic channel that
certain molecules or ions can use as a tunnel
, Page |4
18. Ion Channels - correct answer - channel proteins that transport ions
19. Gated Channels - correct answer - a transmembrane protein channel
that opens or closes in response to a particular stimulus (usually
electrical).
20. Carrier proteins - correct answer - bind to molecules and change
shape to shuttle them across the membrane
21. Active Transport - correct answer - The movement of substances
across the cell membrane that requires the cell to use energy. Pumping
a solute against its electrochemical gradient requires energy.
22. Sodium-Potassium Pump - correct answer - 2 K+ ions in, 3 Na+ ions
out. A form of active transport that requires energy in the form of ATP.
Also, this allows a cell to maintain a negative membrane potential. The
Na-K pump generates voltage across the membrane and is therefore
classified as an electrogenic pump.
23. Membrane potential - correct answer - The voltage across a cell's
plasma membrane.
