Principles of Biology I BIOL 100 Exam
I
1) A scientist observes that when a specific enzyme is extracted from a cell
membrane, it loses functionality. However, when the membrane is briefly
warmed (increasing fluidity) before extraction, the enzyme retains activity.
This suggests that the enzyme's function in the membrane likely depends
on:
a) The concentration gradient of the substrate it is transporting.
b) Its attachment to the rigid cytoskeleton.
c) Its identity as a peripheral protein loosely bound to the surface.
d) Its ability to move laterally within the fluid lipid environment to
interact with other molecules.
e) Its reliance on the specific charge generated by electrogenic pumps
2) Which of the following is the best description of phagocytosis?
a) The uptake of cholesterol via specific receptor proteins.
b) The continuous "gulping" of extracellular fluid nonspecifically into tiny
vesicles.
c) The secretion of large molecules via the fusion of a vesicle with
the plasma membrane.
d) The extension of pseudopodia to engulf a large particle into a food vacuole.
e) The use of a carrier protein to shuttle ions across the membrane.
3) If a highly water-soluble compound, such as a large protein (lysozyme),
is placed in water, which condition would result in the maximum rate of
dissolution (solvation)?
a) The concentration of dissolved sodium cations (Na+) and chloride
anions (Cl-) are equal inside and outside the crystal surface.
b) The sodium and chlorine ions attract each other so strongly that water
molecules cannot penetrate the lattice structure.
c) The water molecules surrounding the substance maximize the
contact between their charged regions and the ionic/polar regions of
the compound.
d) The water is nonpolar, enabling the ionic bonds to be stabilized.
e) All of the above.
4) Compared to a volume of pure water (pH = 7.0) at 25oC, an equal volume
of a solution with a pH of 3.0 has:
1
, a) 104 times fewer hydrogen ions (H+).
b) 103 times fewer hydrogen ions (H+).
c) 104 times more hydrogen ions (H+).
d) 103 times more hydroxide ions (OH-).
e) Equal concentrations of H+ and OH-.
2
I
1) A scientist observes that when a specific enzyme is extracted from a cell
membrane, it loses functionality. However, when the membrane is briefly
warmed (increasing fluidity) before extraction, the enzyme retains activity.
This suggests that the enzyme's function in the membrane likely depends
on:
a) The concentration gradient of the substrate it is transporting.
b) Its attachment to the rigid cytoskeleton.
c) Its identity as a peripheral protein loosely bound to the surface.
d) Its ability to move laterally within the fluid lipid environment to
interact with other molecules.
e) Its reliance on the specific charge generated by electrogenic pumps
2) Which of the following is the best description of phagocytosis?
a) The uptake of cholesterol via specific receptor proteins.
b) The continuous "gulping" of extracellular fluid nonspecifically into tiny
vesicles.
c) The secretion of large molecules via the fusion of a vesicle with
the plasma membrane.
d) The extension of pseudopodia to engulf a large particle into a food vacuole.
e) The use of a carrier protein to shuttle ions across the membrane.
3) If a highly water-soluble compound, such as a large protein (lysozyme),
is placed in water, which condition would result in the maximum rate of
dissolution (solvation)?
a) The concentration of dissolved sodium cations (Na+) and chloride
anions (Cl-) are equal inside and outside the crystal surface.
b) The sodium and chlorine ions attract each other so strongly that water
molecules cannot penetrate the lattice structure.
c) The water molecules surrounding the substance maximize the
contact between their charged regions and the ionic/polar regions of
the compound.
d) The water is nonpolar, enabling the ionic bonds to be stabilized.
e) All of the above.
4) Compared to a volume of pure water (pH = 7.0) at 25oC, an equal volume
of a solution with a pH of 3.0 has:
1
, a) 104 times fewer hydrogen ions (H+).
b) 103 times fewer hydrogen ions (H+).
c) 104 times more hydrogen ions (H+).
d) 103 times more hydroxide ions (OH-).
e) Equal concentrations of H+ and OH-.
2
