Final answer:
The tertiary structure is expected in an aqueous environment due to the hydrophobic and hydrophilic interactions of amino acids with water, causing the protein to adopt a specific, functional shape.
Step-by-step explanation:
Among the options given, tertiary structure is the one you would expect to find in an aqueous environment. This is because the tertiary structure of a protein involves a three-dimensional folding pattern of the molecule that is largely driven by the hydrophobic and hydrophilic interactions between amino acid side chains and the surrounding water.
In aqueous environments, hydrophobic (water-avoiding) side chains typically cluster away from the water, while hydrophilic (water-attracting) side chains interact more readily with water.
This action results in the protein assuming a specific shape that is functional in biological systems. Alpha helices and beta sheets are elements of secondary structure and may be present within both soluble proteins and membrane proteins, while quaternary structure refers to the association of multiple polypeptide chains.
The structures you would expect to find in an aqueous environment are the tertiary and quaternary structures. The primary structure of a protein consists of the amino acid sequence, while the secondary structure includes the alpha helix and beta sheet. However, these structures are not directly formed in an aqueous environment.
The tertiary structure is the overall three-dimensional structure of the protein that forms as a result of folding and bonding of the secondary structure.
The quaternary structure, on the other hand, occurs when two or more tertiary subunits interact with each other.