Lipids: Structure and function of Phospholipids Flashcards
What is a hydrophilic molecule
A molecule
attracted to water
due to having a charge
Thinking about it, is a hydrophilic WATER LOVING or WATER HATING?
Water loving
Phospholipid is a lipid (TRUE OR FALSE?)
TRUE
What is the diff between phospholipid and triglycerides?
One of the fatty acid molecules is replaced by a phosphate molecule in a phospholipid
How does the joining of the phosphate group occur?
through a condensation reaction between hydroxyl groups on both a glycerol molecule and a phosphoric acid molecule
what covalent bond links the phosphate molecule to the glycerol ?
a phosphate ester bond
What are both the phosphate group and the glycerol together known as ? What are the fatty acid chains known as in a phospholipid molecule?
The head of the phospholipid
The tail of the phospholipid
What happens when the phospholipid is surrounded by water? What is formed?
the hydrogen ions DISSIPATE from the phosphoric acid, forming a phosphate group with a negative charge.
Why? OH groups when losing positive hydrogen ions, leave behind negative oxygen ions and the head gains an overall negative charge
does having a negative charge cause the molecule to become hydrophilic
yes
Are fatty acid tails polar? are they charged?
NO,They are non polar
No, they are not charged
What is a hydrophobic molecule?
a molecule repelled from water due to not having a charge
Can phospholipids form layers on the surface of the water? how?
yes
the hydrophilic heads are attracted to the water and submerged and the hydrophobic heads are repelled by water
What is the name of a
spherical monolayer of phospholipids formed?
micelle
Phospholipids can also form a trilayer in cell membrane true or false?
false
bilayer in the cell membrane
where can we find a phospholipid bilayer?
in the cell membrane
where is the facing of hydrophilic tails and what is the facing of hydrophobic tails?
hydrophillic outwards
hydrophobic inwards
what keeps the membrane fluid?
but what keeps it stable?
the fact that phospholipids can move and slide past each other, however they will never expose the hydrophobic tails to water which keeps the membrane stable
Role of phospholipid bilayer
- electrical insulation
- control what moves in and out of the cell
how is it an electrical insulator?
the inside of a bilayer has no water and does not allow water to flow, so charged ions which are always surrounded by water molecules cannot pass
which molecules can pass through bilayer
small non polar molecules
ex: oxygen and carbon dioxide
