91影视

A thin polar membrane made up of two layers of lipid molecules is known as a lipid bilayer or phospholipid bilayer.The membrane is made up of flat sheets of lipid molecules that create continuous layers.

If the polypeptide chain possesses hydrophobic side chains that engage the lipid tails and can protect its polar backbone, it can enter or traverse the lipid bilayer.

The width of a bilayer is $30A掳$.

The length of a the single turn of 伪 helix is $5.4A掳$.

On calculating,

$$\begin{gathered} No.ofturnsof伪helix=\frac{Widthofthelipidbilayer}{Widthofthelipidbilayerina\sin gleturnof伪helix} \\ =\frac{30A掳}{5.4A掳} \\ =5.6 \end{gathered}$$

The number of residues formed per turn of 伪helix is 3.6 residues.

The number of residues formed in 5.6 turns of 伪 helix is $5.6脳3.6=20$residues.

The transmembrane helices contain more than the minimum number of residues. The additional residues present in the transmembrane helices can form a helix.For protein folding to occur, hydrogen bonding is necessary.

Lipid head groups do not have any role in hydrogen bonding formation. However, the transmembrane helices' extra residues partially meet the hydrogen bonding criteria.