MCQs

High heat increases the kinetic energy of lipid tails, increasing the membrane's fluidity.

The Na+/K+ pump moves ions against their gradients using ATP, defining it as active transport.

Amphipathic molecules are essential for forming the bilayer as they interact with both aqueous and non-aqueous environments.

Transmembrane pumps (like the Na+/K+ pump) use ATP to change conformation and transport ions.

Transmembrane proteins are a subset of integral proteins that traverse both leaflets of the bilayer.

Glycoproteins and glycolipids act as cellular "identity tags" and mediate cell-cell adhesion.

Cell wall thickness is unrelated to the fluidity of the plasma membrane.

Carbohydrate chains are attached to proteins/lipids only on the non-cytosolic side of the membrane.

Passive transport relies on kinetic energy (gradient), while active transport requires metabolic energy (ATP).

Facilitated diffusion requires either channel or carrier proteins to assist polar molecules.

The two hydrocarbon chains (fatty acids) are non-polar and hydrophobic.

The phospholipid bilayer provides the fundamental hydrophobic barrier essential for cellular compartmentalization.

By measuring the surface area of extracted lipids, they determined it was twice the surface area of the RBC.

The membrane is fluid and dynamic, not rigid or crystalline.

In hypertonic environments, the external water potential is lower than the cell, causing water to exit by osmosis.

Channel proteins provide a physical pathway, whereas carrier proteins undergo conformational changes to transport substances.

Osmosis is defined as the net movement of water across a membrane driven by a water potential gradient.

Receptors are usually transmembrane integral proteins that span the membrane to receive signals.

They hypothesized that the lipid bilayer was coated on both sides by globular proteins.