Cell Membrane Structure Flashcards
Why do cell surface membranes surround cells
They act as a barrier between the cell and its environment and they control which substances go in and out of the cell
What does partially permeable mean
They let some molecules go through but not others
What do the membranes between organelles act as
Act as a barrier between the cytoplasm and the cell membrane
What is the basic structure of the cell membrane
Lipids proteins and carbohydrates
What does the cholesterol do in the cell membrane
Gives the membrane stability
Is present in all cell membrane
How does cholesterol restrict movement
The cholesterol molecules fit between the phospholipids and bind to the hydrophobic tails of the phospholipids causing them to pack more closely together which makes the membranes less fluid and more rigid
How does cholesterol help animal cells
It maintains the shape of the cell
Why does the cell membrane have a fluid mosaic structure
The bi layer is fluid because the phospholipids are constantly moving
The bi layer is scattered with proteins which is why it’s called mosaic
What do the channel and carrier proteins do
They allow large molecules and ions to pass through the membrane
What do receptor proteins do
Allow cells to detect chemicals released from other cells
What are glycoproteins
Carbohydrate chain attached to a proteins
How is the head and tail of the phospholipids structured
The head is hydrophilic
The tail is hydrophobic
How is the phospholipids arranged in the bi layer
The heads face out towards the water and the centre is hydrophobic so the membrane doesn’t allow water soluble substances so only contains the tails which as a barrier to dissolved substances
