BioChem C785 - WGU - Module 3 - all questions

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BioChem C785 - WGU - Module 3 - all questions Hb (hemoglobin) binds to CO (carbon monoxide) with a higher affinity than oxygen and stabilizes the R (relaxed) state Correct Answer: True When hem... oglobin 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 More]

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