What chemical characteristic defines the phospholipid bilayer’s interior? a. This substance is hydrophobic.
What chemical characteristic distinguishes the inside of a phospholipid membrane?
The phospholipid bilayer is composed of two layers of phospholipids, having a hydrophobic inside and a hydrophilic outside. In a single phospholipid molecule, the hydrophilic (polar) head group and hydrophobic tails (fatty acid chains) are represented.
Plasmalogens are phospholipids with an alkyl-1-enyl bond at the first fatty acid-binding site (sn1) of the glycerol backbone ( Fig.2 ).32% of the entire phospholipid pool is comprised of plasmalogens within the human heart ( Horrocks, 1972 ). Due to the substitution of an ester linkage with a vinyl ether linkage at the sn2 position, plasmalogens possess a significantly different molecular geometry inside the phospholipid membrane than diacyl phospholipids.
This results in significant changes in lipid packing and membrane fluidity compared to phospholipid membranes mostly composed of diacyl phospholipids ( Han and Gross, 1991 ). It has been proposed that these plasmalogens have a unique function in the stability of membrane enzyme systems and ion channels inside the sarcolemma due to their chemical properties ( Scherrer and Gross, 1989 ; Kako, 1986 ).
Cardiac plasmalogens are abundant in the sarcolemma and sarcoplasmic reticulum and are the predominant phospholipid species inside these organelles ( Scherrer and Gross, 1989 ; Gross, et al., 1984 ; Gross, 1985 ). Furthermore, plasmalogens are greatly enriched in arachidonic acid in the sn2 position of the glycerol backbone, and hence serve as a significant arachidonic acid reservoir in the heart.
FIGURE 2 compares the architectures of plasmalogen and 1-diacyl phospholipids. Together, diacyl and plasmalogen phospholipids provide integral membrane proteins with a lipid bilayer environment that is essential for their continued activity. Consequently, variations in phospholipid quantity or composition can change the activity of these membrane proteins.
This consists of essential proteins involved in the regulation of cellular electrophysiology. Full chapter available at: http://www.sciencedirect.com/science/article/pii/B978012656975950064X
What property of phospholipids makes it possible for them to form the double layer observed in cell membranes?
Due to their hydrophilic and hydrophobic characteristics, phospholipids organize into two layers during the formation of cellular membranes. The phosphate heads in each layer face the aqueous or watery environment on each side, while the hydrophobic tails hide between the layers of phosphate heads.