Question

The portion of transmembrane proteins that cross the lipid bilayer are usually:

• A. α-helices
• B. β-sheets
• C. Turns
• D. Loops

Hint:

Remember that α-helices are commonly found in the hydrophobic regions of lipid bilayers due to their structural compatibility.

Answer 1

The Correct Option is A

The transmembrane regions of proteins are predominantly formed by α-helices due to their ability to interact favorably with the hydrophobic core of the lipid bilayer. The α-helix is a stable structure, with hydrophobic side chains extending outward to interact with the lipid bilayer, while the backbone hydrogen bonds stabilize the helix. In contrast, β-sheets are typically seen in specific pore-forming structures like porins and are less common in simple transmembrane domains.