2.2 - Membrane Structure and Functions Flashcards
Functions of the fluid mosaic model
Separates cell from its external environment
Regulates what enters and leaves the cell
What is the fluid mosaic model made of (4)
Phospholipid Bi-layer
Membrane Proteins
Glycoproteins
Cholesterol
Structure and Function of the Phospholipid Bi-Layer
Structure: 2 layers of phospholipid molecules
Function: Keep cell intact. Regulate all that enters and leaves the cell
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Location and functions of Membrane Proteins
Where: Embedded randomly between the
phospholipids
Function: Give the membrane selective
permeability. Transport larger items through the
membrane. Allow hydrophilic particles to pass
through
6 Membrane Proteins
Receptor, Enzyme, Channel, Gated channel, Cell-identity marker, Cell-adhesion molecule
Receptor Membrane Protein
A receptor that binds to a chemical messenger such as a hormone from another cell.
Enzyme Membrane Protein
An enzyme that breaks down a chemical messenger and terminates its effect.
Channel Membrane Protein
A channel protein that is always open and allows solute to pass into and out of the cell.
Gated Channel Membrane Protein
A gate that opens and closes to allow solutes to pass only at certain times, requires ATP. also allows larger molecules to pass through like glucose
Cell Identity Marker Membrane Protein
A glycoprotein distinguishes the body’s own cells from foreign cells.
Cell-Adhesion molecule
A cell adhesion molecule (CAM) that binds one cell to another.
The structure and functions of glycoproteins
Structure: Proteins with attached sugar molecules
Function: Attachment sites for molecules needing to enter, or for messenger molecules such as hormones. Unique for everyone and recognises our own cells vs others
Cholesterol (Sterols)
Cholesterol is required to establish proper membrane permeability and fluidity.
