Why Would a Transverse Diffusion or Flip-Flop of Membrane Phospholipids

question 19

Multiple Choice

Why would a transverse diffusion or flip-flop of membrane phospholipids from one leaflet to the other be so rare?

• A)Flippases are enzymes which are transiently stable and expressed at low concentrations.
• B)For flip-flop to occur, it would be necessary for the hydrophilic head of a phospholipid to move through the hydrophobic part of the bilayer, an extremely unlikely event.
• C)For flip-flop to occur, it would be necessary for the hydrophobic head of a phospholipid to move through the hydrophilic part of the bilayer, an extremely unlikely event.
• D)Other membrane activities like flexing and lateral shift inhibit phospholipid flip-flop.

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Definitions:

Neurons

Specialized cells transmitting nerve impulses; the basic building blocks of the nervous system.

Synapses

The junctions between neurons that allow for the transmission of chemical or electrical signals, facilitating communication within the brain.

Communication Links

The channels or connections through which information is transmitted from one entity or person to another.

Neurological Pathways

The routes made up of neurons connected by synapses through which electrical signals travel across the nervous system.