Which of the following gases can bind to hemoglobin?

Which factors contribute to the Bohr Effect?

Albumin is created in the liver and is an important protein found in the blood. If a vial of blood is centrifuged, in which of the following layers would albumin be found?

Which of the following cell types does not possess a nucleus in its mature form?

An individual with hemophilia, most likely has a deficiency in which of the following proteins?

Which of the following scenarios will cause the oxygen-hemoglobin dissociation curve to shift to the left?

Which statement regarding blood typing is correct?

Hemoglobin is the principal oxygen-carrying protein in humans. It exists within erythrocytes, and binds up to four diatomic oxygen molecules simultaneously. Hemoglobin functions to maximize oxygen delivery to tissues, while simultaneously maximizing oxygen absorption in the lungs. Hemoglobin thus has a fundamentally contradictory set of goals. It must at once be optimized to absorb oxygen, and to offload oxygen. Natural selection has overcome this apparent contradiction by making hemoglobin exquisitely sensitive to conditions in its microenvironment.

One way in which hemoglobin accomplishes its goals is through the phenomenon of cooperativity. Cooperativity refers to the ability of hemoglobin to change its oxygen binding behavior as a function of how many other oxygen atoms are bound to the molecule.

Fetal hemoglobin shows a similar pattern of cooperativity, but has unique binding characteristics relative to adult hemoglobin. Fetal hemoglobin reaches higher saturation at lower oxygen partial pressure.

Because of cooperativity, adult and fetal oxygen-hemoglobin dissociation curves appear as follows.

Beyond its ability to carry oxygen, hemoglobin is also effective as a blood buffer. The general reaction for the blood buffer system of hemoglobin given below.

H+ + HbO2 ←→ H+Hb + O2

Hemoglobin is the most important component of red blood cells. How are red blood cells different from other cells of the body?

Bilirubin is a byproduct of heme catabolism, and is excreted in the bile and stool. Bilirubin is likely derived from processes in what cell type?

Carbonic anhydrase is a very important enzyme that is utilized by the body. The enzyme catalyzes the following reaction:

A class of drugs that inhibits this enzyme is carbonic anhydrase inhibitors (eg. acetazolamide, brinzolamide, dorzolamide). These drugs are commonly prescribed in patients with glaucoma, hypertension, heart failure, high altitude sickness and for the treatment of basic drugs overdose.

In patients with hypertension, carbonic anhydrase inhibitors will prevent the reabsorption of sodium chloride in the proximal tubule of the kidney. When sodium is reabsorbed back into the blood, the molecule creates an electrical force. This electrical force then pulls water along with it into the blood. As more water enters the blood, the blood volume increase. By preventing the reabsorption of sodium, water reabsorption is reduced and the blood pressure decreases.

When mountain climbing, the atmospheric pressure is lowered as the altitude increases. As a result of less oxygen into the lungs, ventilation increases. From the equation above, hyperventilation will result in more being expired. Based on Le Chatelier’s principle, the reaction will shift to the left. Since there is more bicarbonate than protons in the body, the blood will become more basic (respiratory alkalosis). To prevent such life threatening result, one would take a carbonic anhydrase inhibitor to prevent the reaction from shifting to the left.

Carbonic anhydrase inhibitors are useful in patients with a drug overdose that is acidic. The lumen of the collecting tubule is nonpolar. Due to the lumen's characteristic, molecules that are also nonpolar and uncharged are able to cross the membrane and re-enter the circulatory system. Since carbonic anhydrase inhibitors alkalize the urine, acidic molecules stay in a charged state.

How will excess intake of a carbonic anhydrase inhibitor affect the hemoglobin dissociation curve?