NBEO Biochemistry Practice Exam

Albumin has a globular tertiary protein structure, which is characterized by its compact, folded shape that allows it to be soluble in water. The globular structure is formed through multiple interactions, such as hydrogen bonds, ionic bonds, and hydrophobic interactions among the amino acid side chains. This structure is essential for its function in the body, particularly its role in transporting various substances in the bloodstream, including hormones, vitamins, and drugs.

The globular shape of albumin allows it to easily interact with other molecules, making it an efficient carrier protein. This solubility in an aqueous environment is crucial for its biological functions, contrasting with fibrous proteins, which typically form elongated, structural fibers and are usually insoluble in water.

The other choices, such as fibrous, spherical, or multi-layered, do not accurately describe albumin's structure. Fibrous proteins are more rigid and serve structural roles instead of dynamic functions like transport. "Spherical" could describe the overall appearance of some proteins but does not capture the specific characteristics of globular proteins. "Multi-layered" is also not a term typically used to define protein tertiary structure, which is better described by its compact and folded formation inherent to globular proteins like albumin.