BIOL 235 MIDTERM 1 ACTUAL EXAM 2026
TEST BANK QUESTIONS WITH CORRECT
ANSWERS
⩥ Integral Proteins. Answer: Amphipathic proteins which extend into or
through the lipid bilayer. Hydrophilic regions protrude into either watery
extracellular fluid or the cytosol. Most are transmembrane proteins and
glycoproteins.
⩥ Transmembrane Proteins. Answer: Span entire lipid bilayer and
protrude into both the cytosol and extracellular fluid
⩥ Glycoproteins. Answer: Have carbohydrate groups attached to the
ends that protrude into the extracellular fluid. These carbohydrates are
called oligosaccharides (2 - 60 monosaccharides, either straight or
branched). They form glycocalyx.
⩥ Glycocalyx. Answer: Extensive sugary coating formed by the
carbohydrate parts of glycoproteins and glycolipids. Acts as a molecular
"signature" that enables cells to recognize each other. e.g. detect
"foreign" glycocalyx to destroy invading organisms.
⩥ Peripheral Proteins. Answer: Not firmly embedded in the membrane.
Attached to the polar heads of membrane lips or to integral proteins at
,the inner or outer surface of the membrane. Help support plasma
membrane, anchor integral proteins, participate in mechanical activities.
⩥ Ion Channel. Answer: Integral proteins. Pores or holes that specific
ions can flow through. Most are selective.
⩥ Carriers. Answer: Integral proteins. Selectively moves a polar
substance or ion from one side of the membrane to the other. Also
known as transporters.
⩥ Receptors. Answer: Integral proteins. Serve as cellular recognition
sites. Each type recognizes/binds a specific type of molecule. The
specific molecule that binds to a receptor is called a ligand.
⩥ Enzymes. Answer: Integral or peripheral proteins. Catalyze specific
chemical reactions.
⩥ Linkers. Answer: Integral or peripheral proteins. Anchor proteins in
the plasma membrane of neighbouring cells to one another or to protein
filaments inside and outside of the cell.
⩥ Cell-identity markers. Answer: glycoproteins and glycolipids. Enable
a cell to (1) recognize cells of the same kind during tissue formation or
(2) recognize/respond to potentially dangerous foreign cells. e.g. wrong
blood types clumping together.
, ⩥ Selective Permeability. Answer: Plasma membrane allows some
substances to pass more readily than others. Permeability varies.
⩥ High Permeability. Answer: Non-polar molecules (O2, CO2, steroids).
⩥ Moderate Permeability. Answer: Small, uncharged polar molecules
(H2O, urea). Can cross the membrane unassisted.
⩥ Impermeability. Answer: Ions and large uncharged polar molecules
(glucose). Uses channels and carriers
⩥ Concentration Gradient. Answer: Difference in concentration of a
chemical from one place to another, such as from inside to outside of the
plasma membrane.
⩥ Electrical Gradient. Answer: Difference in distribution of positive and
negative ions between the two sides of the plasma membrane. Inner
surface is more negative, while outside surface is more positive. Because
it occurs across the plasma membrane, this difference is termed
membrane potential.
⩥ Electrochemical Gradient. Answer: Combined influence of the
concentration gradient and electrical gradient on movement of a
particular ion.
TEST BANK QUESTIONS WITH CORRECT
ANSWERS
⩥ Integral Proteins. Answer: Amphipathic proteins which extend into or
through the lipid bilayer. Hydrophilic regions protrude into either watery
extracellular fluid or the cytosol. Most are transmembrane proteins and
glycoproteins.
⩥ Transmembrane Proteins. Answer: Span entire lipid bilayer and
protrude into both the cytosol and extracellular fluid
⩥ Glycoproteins. Answer: Have carbohydrate groups attached to the
ends that protrude into the extracellular fluid. These carbohydrates are
called oligosaccharides (2 - 60 monosaccharides, either straight or
branched). They form glycocalyx.
⩥ Glycocalyx. Answer: Extensive sugary coating formed by the
carbohydrate parts of glycoproteins and glycolipids. Acts as a molecular
"signature" that enables cells to recognize each other. e.g. detect
"foreign" glycocalyx to destroy invading organisms.
⩥ Peripheral Proteins. Answer: Not firmly embedded in the membrane.
Attached to the polar heads of membrane lips or to integral proteins at
,the inner or outer surface of the membrane. Help support plasma
membrane, anchor integral proteins, participate in mechanical activities.
⩥ Ion Channel. Answer: Integral proteins. Pores or holes that specific
ions can flow through. Most are selective.
⩥ Carriers. Answer: Integral proteins. Selectively moves a polar
substance or ion from one side of the membrane to the other. Also
known as transporters.
⩥ Receptors. Answer: Integral proteins. Serve as cellular recognition
sites. Each type recognizes/binds a specific type of molecule. The
specific molecule that binds to a receptor is called a ligand.
⩥ Enzymes. Answer: Integral or peripheral proteins. Catalyze specific
chemical reactions.
⩥ Linkers. Answer: Integral or peripheral proteins. Anchor proteins in
the plasma membrane of neighbouring cells to one another or to protein
filaments inside and outside of the cell.
⩥ Cell-identity markers. Answer: glycoproteins and glycolipids. Enable
a cell to (1) recognize cells of the same kind during tissue formation or
(2) recognize/respond to potentially dangerous foreign cells. e.g. wrong
blood types clumping together.
, ⩥ Selective Permeability. Answer: Plasma membrane allows some
substances to pass more readily than others. Permeability varies.
⩥ High Permeability. Answer: Non-polar molecules (O2, CO2, steroids).
⩥ Moderate Permeability. Answer: Small, uncharged polar molecules
(H2O, urea). Can cross the membrane unassisted.
⩥ Impermeability. Answer: Ions and large uncharged polar molecules
(glucose). Uses channels and carriers
⩥ Concentration Gradient. Answer: Difference in concentration of a
chemical from one place to another, such as from inside to outside of the
plasma membrane.
⩥ Electrical Gradient. Answer: Difference in distribution of positive and
negative ions between the two sides of the plasma membrane. Inner
surface is more negative, while outside surface is more positive. Because
it occurs across the plasma membrane, this difference is termed
membrane potential.
⩥ Electrochemical Gradient. Answer: Combined influence of the
concentration gradient and electrical gradient on movement of a
particular ion.
