Topic 2 - Cell Membranes Flashcards
What is meant by fluidity and mosaic in the fluid mosaic model?
Fluidity: phospholipids can move laterally making the membrane flexible and self-sealing.
Mosaic: proteins are scattered throughout the phospholipid layer tiles in a mosaic.
What is the structure of the phospholipid bilayer?
Hydrophilic heads face outward, interacting with water.
Hydrophobic tails point inward, avoiding water.
This allows lipid-soluble molecules to pass through and prevent the movement of water soluble molecules.
What are intrinsic proteins?
They spam the bilayer and include carrier proteins and proteins that facilitate the movement of molecules across the membrane.
What are extrinsic proteins?
Extrinsic proteins are found on the surface and provide mechanical support or actors receptors in conjunction with glycolipids.
What are the functions of proteins in the phospholipid bilayer?
– aid of substances
– Provide mechanical support
– Actors receptors for hormones and other signalling molecules.
What is cholesterol?
It is embedded within the bilayer.
– Increases rigidity by reducing the lateral movement of phosphor lipids.
– Prevent the leakage of water and ions due to its hydrophobic nature.
What are glycolipids?
Made of carbohydrates bound to lipids.
Extends from the surface of the cell membrane.
– Act as cell surface receptors for specific molecules.
– Facilitate cell adhesion to form tissue .
What are glycoproteins?
Made of carbohydrates attached to extrinsic proteins
– Actors receptors for signalling molecules like neurotransmitters.
– Enable cell recognition.
– Aid cell adhesion form tissue
What is selective permeability?
Controls the entry and exits of substances such as ions, nutrients, and waste.
Maintains the internal environment of the cell or organelle.
What does flexibility allow in the bilayer?
The fluid nature allows membranes to change shape important processes like endocytosis and exocytosis.
