Membranes and Membrane Proteins

Flashcards based on the key concepts regarding membranes and membrane proteins.

What are the four properties of biomembranes?

Fluid, Closed compartments, Semi-permeable, Asymmetric.

What are the three classes of membrane proteins?

Integral, lipid-linked, peripheral.

What is a characteristic of lipid bilayers?

Phospholipids spontaneously form lipid bilayers in aqueous solution due to their amphipathic nature.

What is a key factor that affects membrane fluidity?

Fatty acid length, presence of cis double bonds, and steroid content.

What are the two main types of movement in membrane fluidity?

Rapid lateral diffusion and slow transverse (flip-flop) movement.

How does size affect the permeability of molecules through membranes?

Small, uncharged, or hydrophobic molecules pass freely, while large, hydrophilic, or charged molecules cannot cross.

What is the function of carbohydrates on biomembranes?

Carbohydrates are found exclusively on the exoplasmic face and play a role in cell recognition.

What do integral membrane proteins typically have?

They have distinct domains: cytoplasmic (hydrophilic), transmembrane (hydrophobic), and exoplasmic (hydrophilic).

What are tail-anchored proteins and how are they inserted into membranes?

They require Get3 recognition of the hydrophobic C-terminal tail for insertion.

What determines the orientation of Type II and Type III membrane proteins?

The orientation is determined by positively charged amino acids that are kept in cytosol.