BMS 300 Exam 4 [2026/2027] | UPDATED ACTUAL
Exam Question and Answer | Frequently Tested
Questions
• Concentration gradients -✓✓ Biological membranes have the capacity to separate
ions and produce _________________. Although the membranes themselves are
relatively impervious to ionic movement, transmembrane proteins called ion
channels provide ion specific pathways that permit the movement of ions across
the membrane.
• Osmosis -✓✓ _________ is the movement of water from a region of higher
concentration to a region of lower concentration
• Diffusion -✓✓ ___________ is the movement of small molecules, especially
ions, from a region of higher concentration to a region of lower concentration.
• Fe -✓✓ In regions where partial pressures of O2 are high, O2 enters the blood
stream by binding to ___ on hemoglobin
• cooperative -✓✓ the relationship of O2 and Fe on hemoglobin that the binding of
the first molecule of O2 increases the probability that a second molecule of O2 will
bind and so forth until each Fe atom in each of the four globin chains contains a
molecule of O2.
• hemoglobin -✓✓ The molecule in erythrocytes that binds O2 is ____________.
- oxygenated when each of its four molecules has a molecule of O2 attached.
-reduced or deoxygenated when the O2 leaves the Fe atoms.
-composed of four protein submits each with an O2-carrying Fe
,• CO2 -✓✓ ___ is carried to the lungs in the form of bicarbonate HCO3- which is
facilitated by carbonic anhydrase H2CO3
• motor neurons, CO2, pH, CO2, carbonic acid -✓✓ -breathing requires rhythmic
activity of ________________ that drive the diaphragm.
-The stimulus for increased breathing rate is mostly from the effects of
___________.
-The effects of increased arterial PCO2 are indirect and function through changes
in _____.
-Because _____ is freely diffusible it easily leave the blood, and pass into the
brain.
-In the brain CO2 forms ___________ and yields an increase in the H+
concentration in the cerebral spinal fluid.
• diaphragm, CO2, action potential -✓✓ -The breathing rhythm is controlled by the
waxing and waning of activity in the motor neurons that cause muscle contraction
in the _____________.
-The rate at which this activity cycles is largely regulated by the amount of
________ that dissolves in the cerebral spinal fluid and the interstitial fluid in the
brain.
-A group of neurons in the brain stem located within a few millimeters of the
surface are sensitive to increases in H+ ion concentrations. These neurons respond
to increased H+ by increasing their rate of ___________________ generation.
• respiratory, peripheral chemosensory, PCO2 -✓✓ -The neurons sensitive to
increases in H+ cause motor neurons in the brain stem that activate the diaphragm
to become active.
-These centrally located sensors that monitor pH are the major contributors to
changes in ___________ rate.
, -The __________________ neurons are located in the carotid and aortic bodies.
These neurons are sensitive to changes in arterial O2 and CO2. Their contribution
to changes in respiratory rate are small compared to the effects of the central
receptors.
-Changes in arterial PO2 can effect respiratory rate and tidal volume, but arterial
PO2 levels must fall below 60 mm of Hg before these changes have a significant
effect on respiration rate.
-The peripheral chemosensors are far more sensitive to changes in ________ than
to changes in PO2. However, the major driving force for changes in respiratory
rate is the change in pH that is sensed by neurons in the medulla.
• Carbonic Anhydrase -✓✓ _______________ increases the rate of carbonic acid
formation from CO2 and H2O. Once H2CO3 is formed, it quickly breaks into H+
ions that bind to the amino acids in hemoglobin.
• aquaporins -✓✓ The water channels, called _________, permit water to move
across membranes down its concentration gradient.
• ion pumps, NaK pump. -✓✓ against the concentration gradient (Low to high).
-To do this, requires specialized transmembrane proteins called _______ that
usually use ATP as an energy source to move ions up a concentration gradient, i.e.,
from a region of lower concentration to a region of higher concentration.
-The most common of the ion pumps is the ________
• cotransporter -✓✓ The Na-driven ___________ is the most common of the -----.
These transmembrane proteins use the energy of the Na+ gradient across the
epithelial cell membrane to transport amino acids or glucose into cells.
• renal artery, renal vein -✓✓ Each kidney receives blood from a _________ and is
drained by a __________.
Exam Question and Answer | Frequently Tested
Questions
• Concentration gradients -✓✓ Biological membranes have the capacity to separate
ions and produce _________________. Although the membranes themselves are
relatively impervious to ionic movement, transmembrane proteins called ion
channels provide ion specific pathways that permit the movement of ions across
the membrane.
• Osmosis -✓✓ _________ is the movement of water from a region of higher
concentration to a region of lower concentration
• Diffusion -✓✓ ___________ is the movement of small molecules, especially
ions, from a region of higher concentration to a region of lower concentration.
• Fe -✓✓ In regions where partial pressures of O2 are high, O2 enters the blood
stream by binding to ___ on hemoglobin
• cooperative -✓✓ the relationship of O2 and Fe on hemoglobin that the binding of
the first molecule of O2 increases the probability that a second molecule of O2 will
bind and so forth until each Fe atom in each of the four globin chains contains a
molecule of O2.
• hemoglobin -✓✓ The molecule in erythrocytes that binds O2 is ____________.
- oxygenated when each of its four molecules has a molecule of O2 attached.
-reduced or deoxygenated when the O2 leaves the Fe atoms.
-composed of four protein submits each with an O2-carrying Fe
,• CO2 -✓✓ ___ is carried to the lungs in the form of bicarbonate HCO3- which is
facilitated by carbonic anhydrase H2CO3
• motor neurons, CO2, pH, CO2, carbonic acid -✓✓ -breathing requires rhythmic
activity of ________________ that drive the diaphragm.
-The stimulus for increased breathing rate is mostly from the effects of
___________.
-The effects of increased arterial PCO2 are indirect and function through changes
in _____.
-Because _____ is freely diffusible it easily leave the blood, and pass into the
brain.
-In the brain CO2 forms ___________ and yields an increase in the H+
concentration in the cerebral spinal fluid.
• diaphragm, CO2, action potential -✓✓ -The breathing rhythm is controlled by the
waxing and waning of activity in the motor neurons that cause muscle contraction
in the _____________.
-The rate at which this activity cycles is largely regulated by the amount of
________ that dissolves in the cerebral spinal fluid and the interstitial fluid in the
brain.
-A group of neurons in the brain stem located within a few millimeters of the
surface are sensitive to increases in H+ ion concentrations. These neurons respond
to increased H+ by increasing their rate of ___________________ generation.
• respiratory, peripheral chemosensory, PCO2 -✓✓ -The neurons sensitive to
increases in H+ cause motor neurons in the brain stem that activate the diaphragm
to become active.
-These centrally located sensors that monitor pH are the major contributors to
changes in ___________ rate.
, -The __________________ neurons are located in the carotid and aortic bodies.
These neurons are sensitive to changes in arterial O2 and CO2. Their contribution
to changes in respiratory rate are small compared to the effects of the central
receptors.
-Changes in arterial PO2 can effect respiratory rate and tidal volume, but arterial
PO2 levels must fall below 60 mm of Hg before these changes have a significant
effect on respiration rate.
-The peripheral chemosensors are far more sensitive to changes in ________ than
to changes in PO2. However, the major driving force for changes in respiratory
rate is the change in pH that is sensed by neurons in the medulla.
• Carbonic Anhydrase -✓✓ _______________ increases the rate of carbonic acid
formation from CO2 and H2O. Once H2CO3 is formed, it quickly breaks into H+
ions that bind to the amino acids in hemoglobin.
• aquaporins -✓✓ The water channels, called _________, permit water to move
across membranes down its concentration gradient.
• ion pumps, NaK pump. -✓✓ against the concentration gradient (Low to high).
-To do this, requires specialized transmembrane proteins called _______ that
usually use ATP as an energy source to move ions up a concentration gradient, i.e.,
from a region of lower concentration to a region of higher concentration.
-The most common of the ion pumps is the ________
• cotransporter -✓✓ The Na-driven ___________ is the most common of the -----.
These transmembrane proteins use the energy of the Na+ gradient across the
epithelial cell membrane to transport amino acids or glucose into cells.
• renal artery, renal vein -✓✓ Each kidney receives blood from a _________ and is
drained by a __________.
