MCQs

Mosaic implies a diverse pattern of different components (proteins, lipids, carbs) packed together.

While proteins may contribute more by mass, phospholipids are the most numerous molecules.

Because facilitated diffusion uses a limited number of proteins, the rate can reach a maximum (saturation).

The Robertson model (Unit Membrane) described a fixed, trilaminar structural arrangement.

The fatty acid tails create a hydrophobic region that prevents passage of polar substances.

Most cytoskeletal anchors are peripheral proteins attached to the cytoplasmic surface.

Singer and Nicolson proposed the Fluid Mosaic Model in 1972.

Plants typically have higher levels of unsaturated fats to adapt to ambient temperatures.

Many peripheral proteins are connected to the cytoskeleton on the cytoplasmic side of the membrane.

It is passive (no ATP) but uses a protein facilitator.

Glycoproteins and glycolipids on the surface form the glycocalyx, involved in cell adhesion.

Selective permeability ensures only specific molecules can pass, keeping internal homeostasis.

Membrane proteins can act as enzymes to catalyze reactions at the membrane surface.

Cholesterol restricts the lateral movement of phospholipids, thus decreasing fluidity at high temperatures.

Standard plasma membranes are approximately 7.5 nanometers (or 75 Angstroms) in width.

Maintaining concentration gradients against the electrochemical gradient necessitates active transport.

The "kinks" created by double bonds prevent tight packing, which lowers the melting point and increases fluidity.

Hormones and other signaling molecules bind to glycoprotein receptors on the cell surface.

Peripheral proteins are bound to the surface, not embedded, making them easier to isolate.