BioChem C785 - WGU - Module 3 - all questions
Hb (hemoglobin) binds to CO (carbon monoxide) with a higher affinity than oxygen and stabilizes the R (rel... [Show More] axed) state Correct Answer: True
When hemoglobin changes from the T to the R, it has a high affinity for oxygen Correct Answer: True
When hemoglobin changes from the R to T, it has a low affinity for oxygen Correct Answer: True
Cooperatively refers to Correct Answer: structural changes that increases the affinity for oxygen in hemoglobin
When the oxygen concentration is high, the heme shape is planar. When the oxygen concentration is low, the heme shape is bent shape. Correct Answer: True
The Bohr effect is a relationship between hemoglobin's oxygen binding behavior in conjunction with the pH of the surroundings. When the pH is low, hemoglobin has low affinity for oxygen and releases oxygen Correct Answer: True
Bohr effect is a relationship between hemoglobin's oxygen binding behavior in conjunction with the pH of the surroundings. When the pH is high, hemoglobin has high affinity for oxygen and binds oxygen. Correct Answer: True
Relative to the lungs, the pH in the peripheral tissues is lower, because the CO2 generated by metabolism is converted to bicarbonate, which releases proton (H+) Correct Answer: True
The Bohr effect is a relationship between hemoglobin's oxygen binding behavior in conjunction with the pH of the surroundings. When the H+ ion concentration increases, the pH of the solution decreases. Correct Answer: True
Myoglobin stores oxygen, whereas hemoglobin transports oxygen. Myoglobin has a higher affinity for oxygen compared to hemoglobin Correct Answer: True
Hemoglobin is an oxygen transport protein, whereas myoglobin is an oxygen storage protein. They exhibit different binding curves when plotted on a graph with total partial pressure of the oxygen (x-axis) plotted against the percentage saturation of hemoglobin (y-axis). What pattern of binding curves do these proteins exhibit? Correct Answer: Hemoglobin has a sigmoidal curve whereas the myoglobin has a hyperbolic curve.
Hemoglobin and myoglobin proteins bind to molecular oxygen. However, the protein part of the hemoglobin does not bind directly to the oxygen. Instead a specific atom helps bind the oxygen - Correct Answer: Iron
The symptoms of sickle cell anemia are primarily because red blood cells are misshaped, due to Correct Answer: a mutation in the beta hemoglobin gene which leads to the insertion of valine into the hydrophobic patches on deoxygenated hemoglobin
Relative to the peripheral tissues, the pH in lungs is higher, because Correct Answer: the protons (H+) that were combined with hemoglobin quickly bind to bicarbonate (HCO3-) to form CO2; the CO2 is then exhaled
Why is carbon monoxide poisonous? Correct Answer: it binds hemoglobin 200 times better than oxygen
BPG stabilizes the T (tense) states of hemoglobin Correct Answer: True
Even though the amino acids sequence between subunits of hemoglobin and myoglobin are not exactly the same, there are other similarities between the two proteins. Which level of protein structure is not found in both molecules? Correct Answer: Quarternary
In the deoxygenated state the heme is bent, where as in the oxygenated state, the heme is planar. Correct Answer: True
Fetal hemoglobin binds to oxygen tightly at lower oxygen concentrations since its R state is the preferred structure. Correct Answer: True
When blood pH is low, the heme is in bent shape. When the blood pH is high, the heme is in planar shape. Correct Answer: True
In a firefighter who is brought to the emergency room after entering a burning building, the planar confirmation of the heme group in hemoglobin is preferred Correct Answer: True
Structurally, hemoglobin can bind 4 molecules of oxygen, all of which could potentially be replaced by carbon monoxide. Correct Answer: True
Carbon monoxide outcompetes oxygen for attachment to the heme group of hemoglobin where it is permanently, covalently attached. Correct Answer: True
As carbon monoxide binds to hemoglobin, the protein subunits change conformation to allow carbon monoxide to bind faster, This process is called Correct Answer: positive cooperatively
Carbon monoxide shifts the oxygen-hemoglobin dissociation curve to the left, while carbon dioxide shifts this curve to the right. Based on your knowledge of the Bohr Effect, what is true? Correct Answer: Carbon dioxide decreases the hemoglobin's affinity for oxygen, while carbon monoxide increases it.
Hemoglobin's cooperative binding behavior is key to its physiological function, the binding of which molecules influences this behavior? Correct Answer: Oxygen
Carbonic anhydrase is an important enzyme present in the red blood cells that aids in efficient transportation of carbon dioxide in the form of bicarbonate ions, from tissues to lungs. Correct Answer: True
Hemoglobins ability to bind or release oxygen depends on the pH of the environment. This behavior is known as the Bohr Effect, thus Hemoglobin binds to the oxygen at high pH and releases oxygen at a low pH. Correct Answer: True
Hemoglobin acts as a buffer and controls the pH of the blood by binding to h+ ions. Correct Answer: True
In the lungs, CO2 concentration is low and the pH is high, while in the tissues, the CO2 concentration is high and the pH is low. Correct Answer: True
In the locations where the pH is low, hemoglobin will be in the T state, allowing it to release oxygen more effectively Correct Answer: True
Increased levels of 2,3-BPG will decrease the affinity for oxygen by binding to and stabilizing the T state of hemoglobin. The action of 2,3-BPG allows hemoglobin to release oxygen more effectively, which is similar to the effect of low pH on the action of hemoglobin. Correct Answer: True
In comparison to adult hemoglobin, fetal hemoglobin has a higher affinity for oxygen because it doesn't bind 2,3-BPG. Correct Answer: True
Myoglobin and hemoglobin each have different numbers of subunits and this affects their respective oxygen storage and delivery capabilities. How many subunits do myoglobin and hemoglobin each have? Correct Answer: Myoglobin = 1
Hemoglobin = 4
Addition of oxygen alters the shape of the iron-heme complex, and therefore its absorption of light as indicated by its color change from dark purple (the color of hemoglobin in venous blood) to brilliant scarlet (the color of hemoglobin in arterial blood). Correct Answer: True
Oxygen binding alters the structure of an entire hemoglobin tetramer, so the structures of oxyhemoglobin and deoxyhemoglobin are noticeably different. The oxyhemoglobin conformation is specifically referred to as the R (relaxed) state, whereas the deoxyhemoglobin conformation is referred to as the T (tense) state. Correct Answer: True
Patients with sickle cell anemia have atypical hemoglobin, which will distort the red blood cells into sickle shape during oxygen delivery. The substitution of a hydrophilic amino acid with a hydrophobic amino acid in hemoglobin subunits results in the polymerization of hemoglobin, leading to the sickling of red blood cells. Correct Answer: True
Hemoglobin consists of 4 protein subunits. Each subunit contains a heme group that holds an iron atom, which can bind to: Correct Answer: an oxygen molecule
When binding hemoglobin or myoglobin, CO binds in place of: Correct Answer: oxygen [Show Less]
