Lipids Flashcards
What are lipids
Diverse group of compounds that are insoluble in water but soluble in organic solvents such as ethanol
What is the most common type of lipids
Triglycerides (True fats + Neutral fats)
Other important lipids
Waxes, steroids, cholesterol
What do lipids contain
Carbon, Hydrogen and Oxygen - They have a higher proportion of hydrogen and a lower proportion of oxygen
Role of lipids
To be an energy source
How much energy do lipids provide
More than twice the amount as carbs (38kJ/g)
Where are lipids stored
In adipose tissue
What does adipose tissue do for the body
Heat Insulation - in mammals the tissue underneath the skin reduces heat loss
Protection - the tissue is around delicate organs such as kidneys act as cushion for impacts
Structure of Triglycerides
Made from a glycerol backbone joined to 3 fatty acid chains
What is glycerol and its formula
an alcohol with the formula C3H8O3 - Contains 3 hydroxyl (OH) groups
Structure of fatty acids
Long-chain hydrocarbons containing a carboxylic (COOH) group at one end
General formula for a fatty acid
CH3(CH2)nCOOH where n is normally an even number
When is an ester bond formed
In a condensation reaction between one of the OH groups of the glycerol, and the COOH group of the fatty acid. Produces one molecule of water
What can the three fatty acids in a triglyceride be
Can be the same or different
What do the type o fatty acids in a triglyceride affect
Its properties such as melting points
Structure of saturated fatty acids
Single bonds between carbon atoms - Makes molecule straight
Structure of unsaturated fatty acids
Double bonds between carbon atoms - Creates a kink to the chain
Structure of monounsaturated fatty acids
One double bond
Structure of polyunsaturated fatty acids
Contain two or more double bonds
How many fatty acids to phospholipids contain
two
What group is joined to the third hydroxyl group of the glycerol molecule
A polar phosphate group
What is the group that is usually bound to the phosphate group and what does it affect
An alcohol group (‘X’) it affects properties of the phospholipid
What is the word for a molecule that has both hydrophilic and hydrophobic sections
Amphipathic
