Final Answer:
The correct statement is Hemoglobin is composed of four identical protein subunits. Thus the correct option is (E).
Step-by-step explanation:
Hemoglobin is a crucial protein responsible for oxygen transport in the blood. Each hemoglobin molecule consists of four protein subunits, commonly referred to as globins. These globins are arranged in a quaternary structure, forming a tetramer. Importantly, the four subunits are identical in structure, creating a symmetrical and functional protein.Thus the correct option is (E).
The composition of hemoglobin contradicts options B, C, and D. It is not a dimer, as it consists of four subunits, and it does not have binding sites for nitrogen gas; instead, it binds to oxygen. Additionally, hemoglobin is not composed of two different types of protein subunits, eliminating option D. The correct understanding lies in recognizing hemoglobin's tetrameric structure, where each of the four subunits is identical.
In a mathematical perspective, considering the tetrameric nature of hemoglobin, if we denote each subunit as X, the overall structure can be represented as (X)_4. This signifies the presence of four identical subunits. This arrangement is fundamental to hemoglobin's function, allowing it to bind and transport oxygen efficiently. Therefore, the correct statement, option E, aligns with the well-established structure of hemoglobin.