NAU BIO 344 POSNER FINAL
EXAM 2025 UPDATED
QUESTIONS NEW!!!
In a polarized cell, a barrier is created by a specific type of intercellular junction that maintains
the separation of membrane proteins and between the apical and the basal sides of the cell. This
barrier is called a: - CORRECT ANSWER>>>tight junction
What secondary structure found in proteins is often used to enable it to cross a membrane? -
CORRECT ANSWER>>>alpha helices
An inhibitory acetylcholine receptor would - CORRECT ANSWER>>>be a K+ channel
The nonpolar part of a phospholipids consists of - CORRECT ANSWER>>>fatty acid chains
Which of the following is true concerning passive transport and active transport: - CORRECT
ANSWER>>>passive transport transfers molecules down an electrochemical gradient while
active transport transfers molecules against an electrochemical gradient
An example of an amphiphilic phosphoglyceride is: - CORRECT
ANSWER>>>phosphatidlyserine
Reactions that add a phosphate to specific sites on proteins in an ATP dependent manner are
important in cell signaling. The type of enzyme that catalyzes this reaction is: - CORRECT
ANSWER>>>a protein kinase
In a depolarized membrane, repolarization of the neural membrane would occur as a result of: -
CORRECT ANSWER>>>opening of K+ channels
How does an action potential travel down an axon? - CORRECT ANSWER>>>voltage gated
Na+ channels go from closed to open to inactivated in an orchestrated sequential manner
In the presynaptic nerve cell, opening of voltage gated Ca+2 channels at the nerve terminal leads
to: - CORRECT ANSWER>>>exocytosis of the contents of secretory vesicles into the synaptic
cleft
The Na+-K+ pump requires ______ molecule(s) of ATP to transport ______ Na+ ions out of the
cell and _______ K+ ions into the cell. - CORRECT ANSWER>>>1, 3, 2
Phospholipase C and Phospholipase A1 differs differ - CORRECT ANSWER>>>in the specific
site where they cleave phospholipids
Which of the following are used to transport K+ ions against their electrochemical gradient? -
CORRECT ANSWER>>>the sodium potassium pump
, Why is it that in a resting neuron with K+ leak channels open, there are different concentrations
of K+ ions on the two sides of the plasma membrane? - CORRECT ANSWER>>>the membrane
potential of a cell is negative and thus the equilibrium concentration of positively charged K+
ions is higher inside than outside the cell.
Phosphatidylinositol 3-Kinase (also known as PI3K) is a lipid kinase. The 3 is letting you know
that: - CORRECT ANSWER>>>it catalyzes the addition of a phosphate to the 3 position of the
inositol ring.
A glycolipid that is part of the plasma membrane will be found: - CORRECT ANSWER>>>only
on the side of the bilayer that faces away from the cell (towards the extracellular fluid)
When transporting a negatively charged ion through a ligand gated ion channel across the plasma
membrane, which of the following is True? - CORRECT ANSWER>>>the direction of transport
is determined by both the concentration gradient and the membrane potential
Both lipid and protein molecules can diffuse in the plane of a membrane. This is referred to as: -
CORRECT ANSWER>>>Lateral diffusion
The forces that hold together the lipids in the membranes that surround organelles are: -
CORRECT ANSWER>>>Non-Covalent interactions
A prokaryotic organism is isolated from a hydrothermal vent in Yellowstone national park where
despite the fact that the temperature is extremely high, it has been thriving. In the plasma
membrane of such an organism, which of the following concerning its phospholipid composition
will help it adapt to the high temperature of its environment? - CORRECT ANSWER>>>a
predominance of long chain saturated fatty acids
The reason that an action potentials cannot move backward is: - CORRECT
ANSWER>>>voltage gated sodium ion channels cannot go directly from the inactive state to
open
The sodium potassium pump is a - CORRECT ANSWER>>>P-type ATPase
The plasma membrane of an animal cell will contain which of the following: - CORRECT
ANSWER>>>proteins
Which of the following causes a kink (or bend) in the fatty acid chains in a lipid molecule -
CORRECT ANSWER>>>double bonds
The reaction that converts PI 4,5 bisphosphate (PI(4,5)P2) to PI 3,4,5 trisphosphate (PI(3,4,5)P3)
in an ATP dependent manner is an important reaction in cell signaling. The enzyme that
catalyzes this reaction is: - CORRECT ANSWER>>>PI 3-kinase
EXAM 2025 UPDATED
QUESTIONS NEW!!!
In a polarized cell, a barrier is created by a specific type of intercellular junction that maintains
the separation of membrane proteins and between the apical and the basal sides of the cell. This
barrier is called a: - CORRECT ANSWER>>>tight junction
What secondary structure found in proteins is often used to enable it to cross a membrane? -
CORRECT ANSWER>>>alpha helices
An inhibitory acetylcholine receptor would - CORRECT ANSWER>>>be a K+ channel
The nonpolar part of a phospholipids consists of - CORRECT ANSWER>>>fatty acid chains
Which of the following is true concerning passive transport and active transport: - CORRECT
ANSWER>>>passive transport transfers molecules down an electrochemical gradient while
active transport transfers molecules against an electrochemical gradient
An example of an amphiphilic phosphoglyceride is: - CORRECT
ANSWER>>>phosphatidlyserine
Reactions that add a phosphate to specific sites on proteins in an ATP dependent manner are
important in cell signaling. The type of enzyme that catalyzes this reaction is: - CORRECT
ANSWER>>>a protein kinase
In a depolarized membrane, repolarization of the neural membrane would occur as a result of: -
CORRECT ANSWER>>>opening of K+ channels
How does an action potential travel down an axon? - CORRECT ANSWER>>>voltage gated
Na+ channels go from closed to open to inactivated in an orchestrated sequential manner
In the presynaptic nerve cell, opening of voltage gated Ca+2 channels at the nerve terminal leads
to: - CORRECT ANSWER>>>exocytosis of the contents of secretory vesicles into the synaptic
cleft
The Na+-K+ pump requires ______ molecule(s) of ATP to transport ______ Na+ ions out of the
cell and _______ K+ ions into the cell. - CORRECT ANSWER>>>1, 3, 2
Phospholipase C and Phospholipase A1 differs differ - CORRECT ANSWER>>>in the specific
site where they cleave phospholipids
Which of the following are used to transport K+ ions against their electrochemical gradient? -
CORRECT ANSWER>>>the sodium potassium pump
, Why is it that in a resting neuron with K+ leak channels open, there are different concentrations
of K+ ions on the two sides of the plasma membrane? - CORRECT ANSWER>>>the membrane
potential of a cell is negative and thus the equilibrium concentration of positively charged K+
ions is higher inside than outside the cell.
Phosphatidylinositol 3-Kinase (also known as PI3K) is a lipid kinase. The 3 is letting you know
that: - CORRECT ANSWER>>>it catalyzes the addition of a phosphate to the 3 position of the
inositol ring.
A glycolipid that is part of the plasma membrane will be found: - CORRECT ANSWER>>>only
on the side of the bilayer that faces away from the cell (towards the extracellular fluid)
When transporting a negatively charged ion through a ligand gated ion channel across the plasma
membrane, which of the following is True? - CORRECT ANSWER>>>the direction of transport
is determined by both the concentration gradient and the membrane potential
Both lipid and protein molecules can diffuse in the plane of a membrane. This is referred to as: -
CORRECT ANSWER>>>Lateral diffusion
The forces that hold together the lipids in the membranes that surround organelles are: -
CORRECT ANSWER>>>Non-Covalent interactions
A prokaryotic organism is isolated from a hydrothermal vent in Yellowstone national park where
despite the fact that the temperature is extremely high, it has been thriving. In the plasma
membrane of such an organism, which of the following concerning its phospholipid composition
will help it adapt to the high temperature of its environment? - CORRECT ANSWER>>>a
predominance of long chain saturated fatty acids
The reason that an action potentials cannot move backward is: - CORRECT
ANSWER>>>voltage gated sodium ion channels cannot go directly from the inactive state to
open
The sodium potassium pump is a - CORRECT ANSWER>>>P-type ATPase
The plasma membrane of an animal cell will contain which of the following: - CORRECT
ANSWER>>>proteins
Which of the following causes a kink (or bend) in the fatty acid chains in a lipid molecule -
CORRECT ANSWER>>>double bonds
The reaction that converts PI 4,5 bisphosphate (PI(4,5)P2) to PI 3,4,5 trisphosphate (PI(3,4,5)P3)
in an ATP dependent manner is an important reaction in cell signaling. The enzyme that
catalyzes this reaction is: - CORRECT ANSWER>>>PI 3-kinase
