What does it mean when the cell membrane is a phospholipid bi layer?
December 17, 2014 10:49PM
Phospholipids are a structural component of the environment
Asked in iPhone, Cell Biology (cytology)
Does iPhone have cell membrane?
Asked in Genetics
What does it mean to say that the cell membrane is semipermeable?
It means that the cell membrane, which is composed of phospholipid bilayer, cholesterol, glycoprotein, glycolipid, intrinsic proteins and extrinsic proteins, only allows certain molecules to pass through. These molecules include small, non-polar molecules. Polar molecules are unable to pass through the phospholipid bilayer (cell membrane) because they are repelled by the hydrophobic core of the cell. Large molecules are unable to pass through the cell membrane due to the tight packing of the phospholipid bilayer. Sometimes, small polar molecules are able to pass through the phospholipid bilayer because of the transient pores that form. Hence, due to the fact that the cell membrane controls what moves in and out of the cell, it is termed as partially permeable (semi-permeable).
What does it mean for a phospholipid membrane to be selectively permeable?
Asked in Cell Biology (cytology)
What does it mean for the cell membrane to be a highly selective barrier?
Asked in Genetics, Cell Biology (cytology)
What does it mean if a cell membrane is selectively permiable?
Asked in Biology, Cell or Plasma Membranes
What does it mean to say the cell membrane is selectively permeable?
A cell membrane is selectively permeable, often referred to as being semi-permeable because it only allows specific substances to enter the cell, and keeps others out. This means that the cell membrane will allow certain molecules, but not others, through the cell. Small molecules can fit through the phospholipid bilayer passively (without requiring energy) and do not require any help to pass through the membrane. Other molecules (specifically large or polar ones) are not immediately permitted through the membrane and require active transport (using energy)