Module 2.1.5 Biological Membranes Brewer Flashcards
What is the plasma membrane?
-partially permeable barrier between the cell and its environment
What does the plasma membrane do?
-controls what enters and leaves the cell
-site of some chemical reactions
-site of cell signalling
What is compartmentalisation?
Membranes keep the inside of organelles separate from the cytoplasm
What is cell signalling?
-communication between cells and cell recognition
-a molecule released by one cell attaches another and causes a response
Components of the fluid mosaic model
-glycoprotein
-glycolipid
-cholesterol
-carrier protein
-intrinsic protein
-channel protein
-phospholipid bilayer
What does the phospholipid bilayer do?
Provide a barrier to large polar molecules
How thick is the phospholipid bilayer?
7nm
What can pass through the phospholipid bilayer?
-fat soluble substances
-very small molecules
Eg
-steroids , water, cholesterol
What does cholesterol do?
-stabilises the membrane
-regulates the fluidity by binding to phospholipids
-reduces the permeability to charges particles
What are glycolipids?
-carbohydrates and lipids
What are glycoproteins?
-carbohydrates and proteins
What do glycolipids and glycoproteins do ?
-stabilise the membrane by forming H bonds with surrounding water molecules
CONTAIN
-receptors -> for messenger molecules in cell signalling, drugs, hormone and antibodies
-antigens -> for self recognitions and the immune response
What are extrinsic proteins?
(Peripheral proteins)
-present in one side of the bilayer
-normally have hydrophilic R-groups on their surface
What are intrinsic proteins?
-span the width of the membrane
What do intrinsic do?
-transport water soluble charged particles
