Ch.7 Membrane Structure and Function

Question 1

Selective Permeability

Answer 1

A property of biological membranes that allows them to regulate the passage of substances across them

Question 2

Amphipathic

Answer 2

Having both a hydrophilic region and a hydrophobic region

Question 3

Fluid Mosaic Model

Answer 3

The currently accepted model of the cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids

Question 4

Effect of Cholesterol at High Temps.

Answer 4

Cholesterol makes the membrane less fluid by restraining phospholipid movement (since it is wedged between phospholipid molecules in the plasma membrane)

Question 5

Effects of Cholesterol at Low Temps.

Answer 5

Since cholesterol hinders the close packing of phospholipids, it lowers the temp. required for the membrane to solidify

Question 6

Integral Proteins

Answer 6

A transmembrane protein w/hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and w/hydrophilic regions in contact w/the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein)

Question 7

Peripheral Protein

Answer 7

A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer

Question 8

Integrins

Answer 8

A type of integral transmembrane protein

Question 9

Six Major Functions Performed by Proteins

Answer 9

Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, and attachment to the cytoskeleton and ECM

Question 10

Transport Function of Proteins

Answer 10

A protein that spans the membrane may provide a hydrophilic channel across the membrane that is selective for a particular solute