What is a membrane - Lecture 2 Flashcards
What is the structure of the cell membrane?
Phospholipid bilayer
Proteins - perform most of the membrane-specific functions
Carbohydrates - forms the glycocalyx layer
What does Trilaminar mean?
3 layered
e.g. the phospholipid bilayer
How do phospholipids arrange themselves in the phospholipid bilayer?
Head of phosphoplipid on the outside
Hydrophobic tail on the inside
What are bilayers of lipids called in a solution?
Micelles
What is Cholesterol’s affect on the membrane?
Contributes to the fluidity and stability of the membrane
What are the types of proteins inserted into the membrane?
Integral Proteins
Transmembrane Proteins
Peripheral Proteins
What are the two types of channels in the cell membrane - with regards to ion transfer?
Leak Channels - Open all the time
Voltage-Gated- Channel – Open and closed in response to specific changes in membrane potential
What is the layer of carbohydrates found on the outer cell surface called?
Glycocalyx layer
What roles does the Glycocalyx layer have?
Different cells types have different markers
Role in tissue growth - cells do not overstep their own glycocalyx layer
What are the functions of the lipid bilyaer?
Forms the basic structure of the membrane
Hydrophobic interior serves as a barrier
Responsible for the fluidity of the cell membrane
What are the three types cell junctions?
Desosomes
Tight junctions
Gap Junctions
What is a Desosome?
Adhering junctions that anchor cell together - especially in tissues subject to stretching
What is a Tight Junction?
Join the lateral edges of the epithelial cell near their lumenal membranes.
What is a Gap Junction?
Communicating junctions that allow the movement of charge carrying ions and small molecules between two adjacent cells
What the various functions of specific membrane proteins?
Ion channels Carrier or transport proteins Docking-Marker Acceptors Membrane bound enzymes Receptors Cell adhesion molecules
