1.3 The cell surface membrane Flashcards
(17 cards)
What do phospholipids form?
The bi-layer.
Phosphate heads are hydrophobic or hydrophilic?
Hydrophilic.
Fatty acids are hydrophobic or hydrophilic?
Hydrophobic.
What are the functions of phospholipids?
Make the membrane more flexible, prevent water soluble substances entering and leaving the cell and allow lipid soluble substances to enter and leave the cell.
What is the ‘fluid’ part of the bi-layer?
Phospholipids can move relative to each other - flexible.
What is the ‘mosaic’ part of the bi-layer?
Proteins embedded in the phospholipid bilayer vary in shape, size and pattern.
Where do extrinsic proteins occur?
On the surface or partially embedded in the bi-layer.
What do extrinsic proteins do?
They act to give mechanical support.
In conjunction with what do extrinsic proteins act as cell receptors?
Glycolipids.
Where do intrinsic proteins occur?
Completely span the phospholipid bilayer.
What do intrinsic proteins do?
Some act as carriers to transport water soluble material across the membrane.
What does Cholesterol do?
Makes the membrane more rigid
and stable.
What do Glycoproteins and Glycolipids do?
Involved in cell to cell recognition/ hormone receptors.
Where is cholesterol found in the bi-layer?
Found between phospholipid
molecules.
Where are Glycoproteins and Glycolipids found?
On the outer layer.
What is a glycoprotein/glycolipid?
Where a carbohydrate attaches to a lipid/protein.
What are the functions of proteins in the membrane?
Provide structural support, carry/transport water-soluble substances across the membrane, form recognition sites by identifying cells, adhere cells together, act as receptors and allow active transport across the membrane by forming ion channels.
