Foundations in Biology Module 3.5 Lipids Flashcards
What are the features of lipids
- C,H,O
- Non-polar
- Insoluble in water
- Macromolecules
What are triglycerides made out of
- a glycerol molecule (alcohol)
- 3 fatty acids (carboxylic acid)
What is the type of condensation reaction takes place and the type of bond formed
Esterification
- ester bonds
Define saturated
no double bonds present between carbon atoms in fatty acid chains
- carbon atoms form the maximum number of bonds with hydrogen atoms
Define unsaturated
Fatty acid chains consist of double bonds between some carbon atoms
What is a lipid with 1 double bond called
monounsaturated
What is a lipid with 2/more double bonds called
polyunsaturated
What does the presence of double bonds cause
Molecule to bend/kink meaning it can’t be closely packed together
What can an excess in saturated fats lead to
Coronary heart disease
What can excess fats cause
Obesity
What are the feature of phospholipids
- P,H,C,O
- Phosphate ions (PO4^3-) soluble in water as they contain extra electrons
- A phosphate ion
- Glycerol molecule
- 2 fatty acid tails
Which part of a phospholipid is hydrophobic
Fatty acid tails - repelled by water
Which part of a phospholipid is hydrophilic
Phosphate head - attracted to water
What are sterols and what is its features
- Complex alocohol molecules which are made up of a 4 carbon ring with a hydroxyl group
- Hydrophobic and hydrophilic
Cholesterol is an example
A sterol
Where is cholesterol made
The liver and the intestines
What does cholesterol do
Maintains stability to cell membranes and regulates their fluidity by keeping membranes at low temperatures.
What can cholesterol be used to make
Bile, Vitamin D and steroid hormones
What are the roles of the non-polar nature of lipids
- Membrane formation and hydrophobic barriers
- hormone production
- Electrical insulation for impulse transmission
- Waterproofing e.g birds feathers/ plant leaves
What are the roles of lipids and triglycerides
- A long term energy store storage which is under the skin and around vital organs
- Thermal insulation to reduce heat loss
- Cushioning which protects vital organs e.g. heart
- Bouyancy of aquatic animals
What is the test for lipids
Emulsion test
Process of an emulsion test
- Sample is mixed with ethanol
- Solution is then mixed with water and shaken
What is the reasult of a positive emulsion test
A white emulsion layer forms on top of solution
