BIO 253 EXAM 3 COMPREHENSIVE
EXAMINATION TEST 2026 SOLVED QUESTIONS
ANSWERS GRADED A+
◉ Hemoglobin.
Answer: protein made up of four subunits bound together
subunit consists of a heme and a polypeptide attached to the heme
one molecule can bind four O2 molecules
◉ globin.
Answer: the four polypeptides of a hemoglobin molecule
◉ Forms of Hemoglobin.
Answer: deoxyhemoglobin (Hb) and oxyhemoglobin (HbO2)
◉ percent hemoglobin saturation.
Answer: fraction of oxyhemoglobin molecules relative to
hemoglobin molecules present in a blood sample
,%= (O2 bound to Hb/maximal capacity of Hb to bind O2) *100
◉ oxygen carrying capacity.
Answer: the maximum amount of oxygen that can be transported by
hemoglobin
◉ anemia.
Answer: significant decrease in hemoglobin in the blood
◉ oxygen-hemoglobin dissociation curve.
Answer: quantitative relationship between blood Po2 and o2 with
hemoglobin
◉ what contributes to the Po2 of the blood.
Answer: dissolved oxygen, not oxygen bound to hemoglobin
◉ diffusion gradient of oxygen movement into the blood.
Answer: alveoli to plasma to erythrocytes
◉ diffusion gradient of oxygen in tissue capillaries.
Answer: plasma to interstitial fluid to mitochondria of tissue cells
,◉ exercise effect on o2.
Answer: exercising muscle consumes more O2 which lowers
intracellular and interstitial Po2
this increases the blood-to-cell Po2 which increases the rate of
oxygen diffusion from blood to cell
decrease in erythrocyte Po2 causes additional dissociation of
hemoglobin and oxygen
active hyperemia contributes to increased O2 supply
◉ hemoglobin saturation.
Answer: percent of hemoglobin that has O2 or any other gas bound
to its iron moiety regardless of the red cell concentration
(hematocrit) in the blood
◉ effect of decreased hematocrit.
Answer: hemoglobin can be 100% saturated with o2 but the oxygen-
carrying capacity of the blood will be decreased
◉ factors that influence hemoglobin saturation.
Answer: 1. PCO2
, 2. Temperature (increase = decreased affinity for oxygen, curve to
right)
3. H+ Concentration (increase = decreased affinity for oxygen, curve
to right))
4. DPG/ BPG concentration (increase = decreased affinity for
oxygen)
5. presence of hemoglobin found in fetal blood
◉ fetal hemoglobin.
Answer: has a higher affinity for oxygen than adult hemoglobin
allows adequate oxygen uptake in the placenta to supply the
developing fetus
◉ Carbon Monoxide (CO).
Answer: A colorless, odorless gas that is produced in small
quantities by certain cells of the body and is believed to have
physiologically important functions
toxic at higher concentration; product of incomplete combustion of
hydrocarbons
EXAMINATION TEST 2026 SOLVED QUESTIONS
ANSWERS GRADED A+
◉ Hemoglobin.
Answer: protein made up of four subunits bound together
subunit consists of a heme and a polypeptide attached to the heme
one molecule can bind four O2 molecules
◉ globin.
Answer: the four polypeptides of a hemoglobin molecule
◉ Forms of Hemoglobin.
Answer: deoxyhemoglobin (Hb) and oxyhemoglobin (HbO2)
◉ percent hemoglobin saturation.
Answer: fraction of oxyhemoglobin molecules relative to
hemoglobin molecules present in a blood sample
,%= (O2 bound to Hb/maximal capacity of Hb to bind O2) *100
◉ oxygen carrying capacity.
Answer: the maximum amount of oxygen that can be transported by
hemoglobin
◉ anemia.
Answer: significant decrease in hemoglobin in the blood
◉ oxygen-hemoglobin dissociation curve.
Answer: quantitative relationship between blood Po2 and o2 with
hemoglobin
◉ what contributes to the Po2 of the blood.
Answer: dissolved oxygen, not oxygen bound to hemoglobin
◉ diffusion gradient of oxygen movement into the blood.
Answer: alveoli to plasma to erythrocytes
◉ diffusion gradient of oxygen in tissue capillaries.
Answer: plasma to interstitial fluid to mitochondria of tissue cells
,◉ exercise effect on o2.
Answer: exercising muscle consumes more O2 which lowers
intracellular and interstitial Po2
this increases the blood-to-cell Po2 which increases the rate of
oxygen diffusion from blood to cell
decrease in erythrocyte Po2 causes additional dissociation of
hemoglobin and oxygen
active hyperemia contributes to increased O2 supply
◉ hemoglobin saturation.
Answer: percent of hemoglobin that has O2 or any other gas bound
to its iron moiety regardless of the red cell concentration
(hematocrit) in the blood
◉ effect of decreased hematocrit.
Answer: hemoglobin can be 100% saturated with o2 but the oxygen-
carrying capacity of the blood will be decreased
◉ factors that influence hemoglobin saturation.
Answer: 1. PCO2
, 2. Temperature (increase = decreased affinity for oxygen, curve to
right)
3. H+ Concentration (increase = decreased affinity for oxygen, curve
to right))
4. DPG/ BPG concentration (increase = decreased affinity for
oxygen)
5. presence of hemoglobin found in fetal blood
◉ fetal hemoglobin.
Answer: has a higher affinity for oxygen than adult hemoglobin
allows adequate oxygen uptake in the placenta to supply the
developing fetus
◉ Carbon Monoxide (CO).
Answer: A colorless, odorless gas that is produced in small
quantities by certain cells of the body and is believed to have
physiologically important functions
toxic at higher concentration; product of incomplete combustion of
hydrocarbons
