Question

Hemoglobin is an iron-containing protein (molar mass \(64,458 \mathrm{~g} / \mathrm{mol}\) ) that is responsible for oxygen transport in our blood. Hemoglobin is \(0.35 \%\) iron by mass. Calculate how many iron atoms are in each hemoglobin molecule.

Short answer

There are approximately 4 iron atoms in each hemoglobin molecule.

Step-by-step solution

Determine the Mass of Iron in One Mole of Hemoglobin

Start by calculating the mass of iron in one mole of hemoglobin. We know the molar mass of hemoglobin is \(64,458 \text{ g/mol}\) and hemoglobin is \(0.35\%\) iron by mass. Using this percentage, the mass of iron in one mole of hemoglobin can be calculated as follows:\[ \text{Mass of Iron} = \left(\frac{0.35}{100}\right) \times 64,458 \text{ g/mol} = 225.603 \text{ g/mol}. \]

Calculate the Moles of Iron in One Mole of Hemoglobin

Next, determine how many moles of iron are present in the 225.603 g of iron calculated. Since the molar mass of iron is \(55.845 \text{ g/mol}\), the number of moles of iron is given by:\[ \text{Moles of Iron} = \frac{225.603 \text{ g/mol}}{55.845 \text{ g/mol}} \approx 4.04 \text{ moles of iron}. \]

Calculate the Number of Iron Atoms per Hemoglobin Molecule

Finally, determine how many iron atoms are found in each hemoglobin molecule using the moles of iron calculated. Since one mole of any substance contains Avogadro's number (\(6.022 \times 10^{23}\)) of molecules, the number of iron atoms in one hemoglobin molecule is approximately 4 because the moles of iron is about 4.

Key concepts

Hemoglobin

Hemoglobin is a vital protein found in red blood cells, responsible for carrying oxygen from the lungs to the tissues throughout the body. It is made up of four protein subunits, each of which can bind to one oxygen molecule. This protein's complex structure is key to its function in oxygen transport, allowing it to effectively capture and release oxygen as needed. Hemoglobin gives red blood cells their characteristic color, due to the iron atoms it contains. Without hemoglobin, our bodies couldn't efficiently deliver oxygen to cells, which is crucial for energy production and overall function.

It is composed mostly of the elements carbon, hydrogen, nitrogen, and oxygen, but the iron content is what allows it to bind oxygen. This binding capacity is crucial for the transport of oxygen from the lungs to tissues and facilitates carbon dioxide transport back to the lungs for exhalation.

• Provides red color to blood.
• Binds with oxygen and carbon dioxide.
• Composed of four subunits.

Iron Atoms

Iron atoms play a crucial role in the function of hemoglobin. Each hemoglobin molecule contains four iron atoms, which are an integral part of the heme groups embedded in the protein. These iron atoms are the reaction sites for oxygen attachment. Due to the presence of these metal ions, hemoglobin can attach to oxygen molecules and transport them efficiently throughout the body.

Iron is an essential nutrient obtained from our diet, and its deficiency can lead to anemia, characterized by low hemoglobin levels. This emphasizes the importance of iron in maintaining healthy blood function. The calculation of iron atoms in the step-by-step solution shows how iron is distributed within hemoglobin, confirming that it accounts for a small but vital part of hemoglobin’s molecular makeup.

• Essential for oxygen binding in blood.
• Central to the heme group in hemoglobin.
• Inadequate iron levels can cause anemia.

Oxygen Transport

Oxygen transport is the primary role of hemoglobin and a fundamental process in human physiology. Hemoglobin's structure allows it to effectively bind to oxygen in the lungs and release it where it is needed in the body. This efficient system is facilitated by the iron atoms within the heme group, which are directly involved in binding to the oxygen.

As blood circulates, the hemoglobin picks up oxygen molecules, mainly in the lung's alveoli, and travels through the bloodstream to deliver oxygen to various cells and tissues. Once the oxygen is released, hemoglobin can then bind to carbon dioxide, a waste product of cellular respiration, and return it to the lungs, where it is expelled from the body. The ability to transport oxygen and carbon dioxide efficiently makes hemoglobin vital to metabolism and energy production.

• Involves transportation from lungs to tissues.
• Supports cellular respiration and energy production.
• Releases carbon dioxide as a waste product.