Multiple Choice
What prevents the Na+ and K+ gradients across the plasma membrane from dissipating in animal cells?
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8. Membrane Structure
Membrane Proteins
Multiple Choice
In the context of membrane proteins, what forms the channels and pumps embedded within the phospholipid bilayer of the plasma membrane?
A
Cholesterol molecules
B
Integral (transmembrane) proteins
C
Peripheral membrane proteins
D
Glycolipids
Verified step by step guidance1
Understand that the plasma membrane is primarily composed of a phospholipid bilayer, which provides a fluid matrix but is impermeable to most water-soluble molecules.
Recognize that membrane proteins are classified into two main types: integral (transmembrane) proteins and peripheral proteins, based on their association with the membrane.
Recall that integral (transmembrane) proteins span the entire phospholipid bilayer and have hydrophobic regions that interact with the lipid tails, allowing them to be stably embedded within the membrane.
Know that these integral proteins form channels and pumps that facilitate the selective transport of ions and molecules across the membrane, which is essential for cellular function.
Peripheral membrane proteins, in contrast, are loosely attached to the membrane surface and do not form channels or pumps, while cholesterol molecules and glycolipids contribute to membrane fluidity and stability but do not form transport pathways.
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