Question

The plasma membrane are composed of specific types of phospholipids that are asymmetrically distributed between the two monolayers of the lipid bilayer. For example, the inner monolayer of the human erythrocyte plasma membrane is primarily composed of phosphatidylethanolamine and phosphatidylserine. On the other hand, the outer monolayer mainly consists of phosphatidylcholine and sphingomyelin. The specific composition and distribution of phospholipids in the two monolayers is continuously maintained.
Select the statements that describe how the transbilayer asymmetry in the lipid bilayer is achieved and maintained.

---The phospholipids in the plasma membrane can freely diffuse within the bilayer. To maintain the asymmetrical distribution within the bilayer, phospholipases continuously replace the phospholipids in each monolayer

---Movement of phospholipids in the plasma membrane from one monolayer to the other requires the polar or charged head groupd to enter the hydrophobic interior of the lipid bilayer. This process requires a large positive change in free-energy, thus making this type of movement unlikely without an input of energy.

---Phospholipids in the plasma membrane are anchored to a specific location in the plasma membrane via strong hydrophobic interactions with neighboring lipids, thus maintaining the asymmetrical distribution of lipids in the bilayer.

---Specific phospholipids in the plasma membrane covalently attach to certain integral membrane proteins. These covalent interactions anchor the phospholipids to specific locations in the plasma membrane and maintain the asymmetrical distribution of lipids in the bilayer.

---Membrane lipids are synthesized in the ER, then modified and targeted to specific locations in the inner and outer monolayers of the plasma membrane

NOTE:

1,3,5 is incorrect

1,2 is incorrect

Answer 1

Answer:

The statements that describe how the trans bilayer asymmetry in the lipid bilayer is achieved and maintained are listed below.

Explanation:

Phospholipids in the plasma membrane are anchored to a specific location in the plasma membrane via strong hydrophobic interactions with neighbouring lipids thus maintaining the asymmetrical distribution of lipids in the bilayer.

Specific phospholipids in the plasma membrane covalently attach to certain integral membrane proteins.These covalent interaction anchor the phospholipid to specific location in the plasma membrane and maintain the asymmetrical distribution of lipids in the bilayer.