Biological Molecules - Lipids Flashcards
1
Q
Describe The Test For Lipids In A Sample
A
- Dissolve Solid Samples In Ethanol
- Add An Equal Volume of Water To Ethanol and Shake
- A Positive Result Will Show A Milky-White Emulsion Formed
2
Q
How Do Triglycerides Form?
A
A Condensation Reaction Between 1 Glycerol Molecule and 3 Fatty Acids To Form Ester Bonds
3
Q
Compare Saturated and Unsaturated Fatty Acids
A
Saturated:
- Only Single Carbon Bonds
- Straight Chain Molecules With Many Contact Points
- Higher Melting Point So Is Solid At Room Temperature
- Found In Animal Fats
Unsaturated:
- Contain Some Double Carbon Bonds
- Are Kinked Molecules So Have Fewer Contact Points
- Lower Melting Point So Is Liquid At Room Temperature
- Found In Plant Oils
4
Q
Relate The Structure of Triglycerides to Its Functions
A
- High Energy:Mass Ratio
- Insoluble Hydrocarbon Chain = No Effect On Water Potential of Cells and Used For Waterproofing
- Slow Conductor of Heat So Can Provide Thermal Insulation
- Less Dense Than Water So Cause For Buoyancy of Aquatic Animals
5
Q
Describe The Structure and Function of Phospholipids
A
Amphipathic Molecule - Glycerol Molecule (Backbone) Attached to 2 Hydrophobic Fatty Acid Tails & 1 Hydrophilic Phosphate Head
- Forms Phospholipid Bilayer In Water = Component Of Membranes
- Tails Can Splay Outwards = Waterproof
6
Q
Compare Phospholipids & Triglycerides
A
- Both Have Glycerol Backbone
- Both May Be Attached To A Variety of Fatty Acids, eg: Saturated, Monounsaturated, Polyunsaturated
- Both Contain Carbon, Hydrogen & Oxygen
- Both Formed by Condensation Reactions
7
Q
Contrast Phospholipids & Triglycerides
A
Phospholipids:
- 2 Fatty Acids & 1 Phosphate Group Attached
- Hydrophilic Head and Hydrophobic Tail
- Used Primarily In Membrane Formation
Triglycerides:
- 3 Fatty Acids Attached
- Entire Molecule Is Hydrophobic
- Used Primarily As A Storage Molecule
8
Q
Are Phospholipids and Triglycerides Polymers?
A
No; They are not made from repeating units - they are macromolecules
