All AP Biology Resources
Example Questions
Example Question #1 : Circulatory Physiology
Which of the following traits is shared by both red blood cells (erythrocytes) and white blood cells (leukocytes)?
They all mature in bone marrow
They are all produced in bone marrow
They all contain mitochondria
They all contain a nucleus
They are all produced in bone marrow
Erythrocytes and leukocytes are both produced and mature in bone marrow, with the exception of T cells, a type of white blood cell that matures in the thymus. Unlike leukocytes, red blood cells contain no nuclei or mitochondria, which could interfere with transporting oxygen, carbon dioxide, and nutrients.
Example Question #1 : Vascular Physiology
Jack has blood type B negative. He is in an accident and needs to receive a blood transfusion. From which of the following blood types can Jack receive blood?
O, Rh+
B, Rh+
AB, Rh-
O, Rh-
O, Rh-
Because Jack has blood type B, he will form antibodies against blood types A and AB, as they contain a foreign antigen that his body will reject. Furthermore, he cannot accept any blood types that are Rh+, as this antigen will also seem foreign to his body. He can thus only accept from the blood types B- and O- (the universal donor type).
Example Question #2 : Circulatory Physiology
Which of the following statements about blood vessels is true?
Arteries contain valves to prevent backflow of blood
Arteries have thicker walls than veins, which have thicker walls than capillaries
Pressure in veins is always higher than it is in arteries
Capillaries contain oxygenated blood only
Arteries have thicker walls than veins, which have thicker walls than capillaries
Arteries have thick, muscular walls that allow for constriction and flow direction, while veins have thin walls to carry blood.
Capillaries have extremely thin walls to allow exchange of oxygen, carbon dioxide, and nutrients with tissues, resulting in both oxygenated and deoxygenated blood in these vessels. Pressure in the arteries is always higher than in veins so that blood can be continuously pushed forward, negating the need for valves to prevent backflow. Such valves are present in veins and help to counteract gravity when returning blood to the heart.
Example Question #2 : Understanding Hemoglobin And Transport
Which of the following will decrease hemoglobin's affinity for oxygen?
Measure affinity while hemoglobin is in the lungs
Decrease the temperature
Decrease the acidity of the blood
Decrease the partial pressure of oxygen
Decrease the partial pressure of oxygen
Hemoglobin will have varying affinity for oxygen depending on its environment. For example, hemoglobin will have a very high affinity for oxygen in the lungs, where most oxygen is loaded onto the hemoglobin molecules. Once hemoglobin goes to the tissues of the body, there is a much lower oxygen tension. This decreased oxygen causes hemoglobin to have a lower affinity for oxygen and release the oxygen to the tissues.
Example Question #1 : Vascular Physiology
Which statement best describes hemoglobin?
It is comprised of alpha and beta proteins and centers around copper
It is comprised only of alpha proteins and centers around iron
It is comprised only of beta proteins and centers around iron
It is comprised of alpha and beta proteins and centers around iron
It is comprised of alpha and beta proteins and centers around iron
Hemoglobin is comprised of two alpha and two beta proteins and uses iron to facilitate oxygen transportation. Some variations of hemoglobin, such as fetal hemoglobin, contain gamma proteins that changes the shape of the protein. Consistent with the theme that structure determines function, fetal hemoglobin has a higher affinity for oxygen than does adult hemoglobin. This is necessary since fetuses lack lungs; they obtain all of their oxygen from the hemoglobin of their mothers.
Example Question #2 : Vascular Physiology
Where does transfer of oxygen to cells occur?
Veins
Capillaries
Arteries
Lungs
Capillaries
Capillaries are the smallest blood vessels, which allow transport of oxygen and other small molecules. There are capillaries involved in gas exchange in the lungs, but it does not involve transfer of oxygen to the cells. Rather, it involves uptake of oxygen by red blood cells from the air inside the alveoli, and removal of carbon dioxide from the blood into the air in the alveoli to be exhaled. All other blood vessels have walls that are too thick to allow transport of any substances across them. The heart is the muscular pump of the circulatory system, which provides the pressure required to drive blood flow.
Example Question #1 : Circulatory Physiology
Which of the following transportation vessels carries deoxygenated blood away from the heart?
Pulmonary arteries
Aorta
Pulmonary veins
Vena cavae
Pulmonary arteries
Arteries carry blood away from the heart, while veins transport blood towards the heart. Because the pulmonary arteries transport blood from the right ventricle towards the lungs to exchange carbon dioxide for oxygen, they contain deoxygenated blood.
The aorta, however, transports oxygenated blood from the left ventricle to the rest of the body for circulation. The pulmonary vein carries oxygenated blood from the lungs to the left ventricle and the vena cavae return deoxygenated blood to the right atrium.
Example Question #1 : Understanding Osmotic And Oncotic Pressure
Which of the following pressure changes would result in decreased fluid movement into the interstitium?
An increase in capillary hydrostatic pressure.
An increase in capillary osmotic pressure.
A decrease in interstitial hydrostatic pressure.
An increase in interstitial osmotic pressure.
An increase in interstitial osmotic pressure.
As fluid moves through the capillary, the hydrostatic pressure decreases from the arteriole end to the venule end (fluid exits the capillary along the gradient). The osmotic pressure in the interstitium is relatively constant, and will be stronger than capillary hydrostatic pressure near the venule end. As a result, an increase in the interstitial osmotic pressure would cause less fluid to enter the interstitium, because there is less area in the bed where the capillary hydrostatic pressure is greater than the interstitial osmotic pressure.
Example Question #2 : Circulatory Physiology
As blood enters the arteriole end of a capillary some fluid generally exits into the interstium. When the blood flows through the venule end of the capillary some of this fluid is returned to the vessel. What best explains this transition?
Interstitial hydrostatic pressure becomes stronger than the capillary osmotic pressure
Capillary hydrostatic pressure becomes stronger than the interstitial osmotic pressure
Interstitial osmotic pressure becomes stronger than capillary hydrostatic pressure
Capillary osmotic pressure becomes stronger than interstitial hydrostatic pressure
Interstitial osmotic pressure becomes stronger than capillary hydrostatic pressure
The capillary is the site of fluid exchange with the body's tissues. This fluid transfer is moderated by two factors: hydrostatic pressure and osmotic pressure. Hydrostatic pressure is the "pushing" force on water due to the presence of more fluid in one region than another. In general, larger fluid volumes generate higher hydrostatic pressure. Osmotic pressure is the "pulling" force on water due to the presence of solutes in solution. Albumin proteins are the main source of osmotic pressure in capillaries, pulling water into the blood.
At the arteriole end of the capillary, the hydrostatic pressure is stronger than the interstitial osmotic pressure and fluid is forced into the interstitium. Osmotic pressure remains relatively constant over the length of the capillary, but hydrostatic pressure drops sharply as it nears the venule end due to the initial loss of fluid volume. At that point, the interstitial osmotic pressure becomes stronger than the capillary's hydrostatic pressure. This forces fluid back into the capillary.
Example Question #1 : Understanding Osmotic And Oncotic Pressure
Why does fluid reenter the capillary from the interstitium at the venule end of the capillary bed?
Osmotic pressure is greater at the venule end of the capillary
Osmotic pressure is lower at the venule end of the capillary
Hydrostatic pressure is greater at the venule end of the capillary
Hydrostatic pressure is lower at the venule end of the capillary
Hydrostatic pressure is lower at the venule end of the capillary
Hydrostatic pressure is the force of the fluid volume against a membrane, while osmotic pressure is related to the protein concentration on either side of a membrane pulling water toward the region of greater concentration.
When fluid enters the capillaries, it is initially pushed out because the hydrostatic pressure pressing outward is greater than the osmotic pressure pushing inward. Although osmotic pressure stays constant throughout the capillary length, hydrostatic pressure decreases towards the venule end of the capillary. This makes the osmotic pressure larger than the hydrostatic pressure, and pushes the fluid back into the capillary.