phospholipids

what is the structure of a phospholipid?

it contains a glycerol and two fatty acids chains and a phosphate group.

is the fatty acid chains hydrophobic or hydrophilic?

hydrophobic

is the phosphate group hydrophobic or hydrophilic?

hydrophilic

what does this dual nature of the phospholipids allow them to do?

arrange themselves into a bilayer in cell membranes.

how are the fatty acid tails joined to the glycerol?

via ester bonds made in condensation reactions

what are the properties of phospholipids?

• amphipathic nature

• forms a bilayer in aqueous solutions

• partially permeable

how does the amphipathic nature of the phospholipids work?

the phosphate head is hydrophilic and interacts with water whereas the hydrophobic fatty acid tails avoid water and face inward in a bilayer.

how does the fact that a phospholipid creates a bilayer in aqueous solutions help with its function?

it helps the structure of the plasma membrane

how does the partially permeable aspect of the phospholipids help them function?

small non polar molecules such as oxygen and carbon dioxide can diffuse through easily. large polar molecules require transport proteins to cross the membrane. water is polar but it is small enough to diffuse through the phospholipid bilayer without a transport protein.

what are the functions of phospholipids?

• major component of cell membranes (phospholipid bilayer)

• provides fluidity to the membrane which allows flexibility and movement. this is because the phospholipids can move laterally.

• acts as a barrier to large water soluble molecules so this helps regulate entry and exit from the cell.