Which of the following statements regarding hydrogen bonding in secondary structures is true? Group of answer choices Both α-helices and β-sheets only use intrachain hydrogen bonds. Both α-helices and β-sheets only use interchain hydrogen bonds. α-helices only use intrachain hydrogen bonds and β-sheets can use either intrachain or interchain hydrogen bonds. α-helices can use either intrachain or interchain hydrogen bonds and β-sheets only use interchain hydrogen bonds.

The correct answer is "α-helices only use intrachain hydrogen bonds and β-sheets can use either intrachain or interchain hydrogen bonds".

Explanation:

Hydrogen bonding are essential forces for the formation of the secondary structures of proteins. The alpha helix is a coiled secondary structure that is stabilized only by intrachain hydrogen bonds, which are formed between the NH and CO groups of the main chain. On the other hand,  β-sheets can use either intrachain or interchain hydrogen bonds for its stabilization. Adjacent chains in β-sheets can run either in the same or opposite directions, which are stabilized by interchain hydrogen bonds.

lithosphere and asthenosphere