BIOL 252 Exam 1 Review Questions and 100% Correct Answers Latest 2026/27-
UNC
1. Cystic fibrosis is a disease characterized by thickened mucus in the airway lumen (on the apical side of
the epithelial cells.) In a theoretical situation, how many of the following would help to produce a more
watery, mobile mucus layer? For the hypothetical ions referred to below: the hypothetical cation has an
equilibrium potential of -100mV and the hypothetical anion has an equilibrium potential of +15mV.
Assume the cell has the same resting membrane potential as a neuron.
I. Having the patient inhale the ligand for ligand-gated cation channels on the apical side of the lung
epithelial cells
II. Having the patient inhale the ligand for ligand-gated anion channels on the apical side of the lung
epithelial cell
III. Adding more anion leak channels to the apical side of the lung epithelial cells
IV. Adding more cation leak channels to the apical side of lung epithelial cells
a. Only one
b. Only two
c. Only three
d. All four
e. None of the above (I-IV)
A cation with an equilibrium potential of -100mV would move OUT at -70mV.
An anion with an equilibrium potential of +15mV would move OUT at -70mV.
Remember that ion channels, once open, allow the movement of ions in whatever direction their
electrochemical gradients drive them. Water would follow via osmosis.
2. During the movement of carbon dioxide into the blood from neuron in the brain, how many membranes
must carbon dioxide pass through? For this question, use the assumptions that carbon dioxide starts in the
neuron cytoplasm and cannot pass through tight junctions, and that not all capillaries are completely
surrounded by astrocytes.
I. 0
II. 1
III. 2
IV. 3
V. 4
It would have to cross the cell membrane of the neuron (1) to get into the ECF of the brain,
and then it would have to cross the endothelial cell membrane (2) to get into the cytoplasm,
and then cross the membrane again (3) to go from the cytoplasm to the blood. Note that the
question doesn’t ask about the membranes of how many CELLS (which would be 2) – it asks
about the number of MEMBRANES themselves that it has to pass through, which is 3. See
below picture for clarification.
Edit: 2 will also be accepted as an answer since it was not clear that the question was asking
how many TIMES the molecule crossed a membrane.
BIOL 252 Exam 1
, 3. Sarah got into a terrible car accident and suffered damage to her brain. Her friend John visited
her at the hospital and asked Sarah if she could remember what happened. Sarah could understand
John but could not form a coherent response with her mouth. What are of the brain did Sarah
most likely damage?
a. Broca’s area
b. Wernicke’s area
c. Hippocampus
d. Medulla oblongata
The best answer here is Broca’s area, since it says that Sarah could understand John, making it likely that
Wernicke’s area was unharmed.
4. Which of the following statements are true?
I. If you were comparing a neuron and an astrocyte from the same individual, they would have the same
DNA and RNA but express different proteins.
II. The same protein can function two different ways in two different cell types.
III. Understanding the individual components of a system allows you to predict its emergent properties.
a) I only
b) II only
c) III only
d) Two of these statements (I-III) are true
e) None of these statements (I-III) are true
BIOL 252 Exam 1
UNC
1. Cystic fibrosis is a disease characterized by thickened mucus in the airway lumen (on the apical side of
the epithelial cells.) In a theoretical situation, how many of the following would help to produce a more
watery, mobile mucus layer? For the hypothetical ions referred to below: the hypothetical cation has an
equilibrium potential of -100mV and the hypothetical anion has an equilibrium potential of +15mV.
Assume the cell has the same resting membrane potential as a neuron.
I. Having the patient inhale the ligand for ligand-gated cation channels on the apical side of the lung
epithelial cells
II. Having the patient inhale the ligand for ligand-gated anion channels on the apical side of the lung
epithelial cell
III. Adding more anion leak channels to the apical side of the lung epithelial cells
IV. Adding more cation leak channels to the apical side of lung epithelial cells
a. Only one
b. Only two
c. Only three
d. All four
e. None of the above (I-IV)
A cation with an equilibrium potential of -100mV would move OUT at -70mV.
An anion with an equilibrium potential of +15mV would move OUT at -70mV.
Remember that ion channels, once open, allow the movement of ions in whatever direction their
electrochemical gradients drive them. Water would follow via osmosis.
2. During the movement of carbon dioxide into the blood from neuron in the brain, how many membranes
must carbon dioxide pass through? For this question, use the assumptions that carbon dioxide starts in the
neuron cytoplasm and cannot pass through tight junctions, and that not all capillaries are completely
surrounded by astrocytes.
I. 0
II. 1
III. 2
IV. 3
V. 4
It would have to cross the cell membrane of the neuron (1) to get into the ECF of the brain,
and then it would have to cross the endothelial cell membrane (2) to get into the cytoplasm,
and then cross the membrane again (3) to go from the cytoplasm to the blood. Note that the
question doesn’t ask about the membranes of how many CELLS (which would be 2) – it asks
about the number of MEMBRANES themselves that it has to pass through, which is 3. See
below picture for clarification.
Edit: 2 will also be accepted as an answer since it was not clear that the question was asking
how many TIMES the molecule crossed a membrane.
BIOL 252 Exam 1
, 3. Sarah got into a terrible car accident and suffered damage to her brain. Her friend John visited
her at the hospital and asked Sarah if she could remember what happened. Sarah could understand
John but could not form a coherent response with her mouth. What are of the brain did Sarah
most likely damage?
a. Broca’s area
b. Wernicke’s area
c. Hippocampus
d. Medulla oblongata
The best answer here is Broca’s area, since it says that Sarah could understand John, making it likely that
Wernicke’s area was unharmed.
4. Which of the following statements are true?
I. If you were comparing a neuron and an astrocyte from the same individual, they would have the same
DNA and RNA but express different proteins.
II. The same protein can function two different ways in two different cell types.
III. Understanding the individual components of a system allows you to predict its emergent properties.
a) I only
b) II only
c) III only
d) Two of these statements (I-III) are true
e) None of these statements (I-III) are true
BIOL 252 Exam 1
