Lipids Flashcards
Lipids
Molecules that are found in fats and oils
Fats
Solid lipids
Oils
Liquid fats
Functions of lipids in our diet
A source of energy for respiration
Functions of lipids as tissue in our body
Adipose tissue/ fat on body:
Stores energy
Insulates the body
Protects the organs from injury
Functions of lipids in our cells
Part of membrane structures around cells and mitochondria
Categories of lipids
Triglycerides
Phospholipids
Triglyceride structure molecule
Molecule of glycerol
Bonded to 3 fatty acids
Fatty acid molecules
Contains carboxylic acid group at one end
Then long chain of carbons surrounded by hydrogen
Saturated fatty acids
Contains only single bonds between the carbon atoms on the long chain
Unsaturated fatty acid
Contains at least one double covalent carbon to carbon bond in the carbon chain
Monounsaturated fatty acid
Contains only 1 double covalent bond in the carbon chain
Polyunsaturated fatty acid
Contains 2 or more double covalent bond double covalent bond in the carbon chain
Glycerol structure
3 carbon atoms bonded to 3 hydroxyl groups each
Rest is bonded to hydrogen
How does 1 glycerol and 3 fatty acids bond together
The 3 OH groups in the acid group of each fatty acid
And the 3 OH groups of the glycerol form an ester bond (oxygen linking each molecule together) and water
Esterification
Forming ester bonds between glycerol and fatty acids
Through condensation = releases water
How are triglycerides digested?
Lipase enzymes break ester bonds which release the 3 fatty acids and glycerol
Requires water = hydrolysis
Features of triglycerides
Insoluble in water (hydrophobic)
Large amounts of energy release
Why are triglycerides hydrophobic?
Because it is non polar so won’t dissolve in the polar molecule water
Why are triglycerides good stores of energy?
Contains many carbon to hydrogen bonds
Which when broken release a lot of energy
Phospholipid structure
Glycerol molecule
Attached to 2 fatty acid molecules (ester bond)
Remaining carbon in the glycerol attaches to phosphate group forming a phosphodiester bond
Phosphate group
PO₄³⁻
Is negatively charged
Is the phosphate group polar?
Yes because there’s an uneven distribution of electrons in its bonding
And negatively charged
Why is the phosphate group hydrophilic?
Because it is a polar molecule so attracts other polar molecules (water)
Simple way to show phospholipid
Circle with 2 lines coming out of it
Circle = polar hydrophilic head (phosphate) and glycerol bonded to the acid group in fatty acids
Lines = non polar hydrophobic fatty acids
Are fatty acids hydrophobic
Yes because it contains no oxygen to hydrogen bonds therefore not a polar molecule
Phospholipids properties
Contains hydrophobic region (fatty acidsl)
Contains hydrophilic region (phosphate group and glycerol)
When phospholipid is put in water
The polar hydrophilic phosphate heads position themselves to interact with them
And the hydrophobic tails cluster away from water molecules
Phospholipid bilayer
Structure formed when phospholipids face themselves where the hydrophilic head interacts with water molecules and hydrophobic tails face away
Phospholipid bilayer use
Forms membranes around cells and inside cells
