Lipids Unit 1.2 Flashcards
How are triglycerides formed
the condensation of 1 glycerol head and 3 fatty acid tails
what bond is formed between glycerol and a fatty acid?
How many bonds are in 1 triglyceride?
- Ester bond
- 3
What do Fatty acids consist of?
- A Hydrocarbon chain (sometimes referred to as R)
- A carboxylic acid group (COOH)
- The whole fatty acid can be referred to as RCOOH
What is the difference between saturated and unsaturated fatty acids?
- Saturated do not have any double bonds between the carbon atoms in the hydrocarbon chain
- Unsaturated have double bond between the carbon atoms in the hydrocarbon chain
how do fatty acids react in water
Non-polar (do not have a charge)
Hydrophobic- repels water
What do triglycerides form in water
- Insoluble droplets
- hydrophobic fatty acid tails face inward shielded from the water by glycerol heads
What is the structure of a phospholipid
-Similar to triglycerides but one fatty acid tail is replaced by a phosphate head
-2 fatty acid tails
-1 gycerol molecule
-1 phosphate head
-
How do phosphate groups act in water
- Phosphate groups are polar (negative charge)
- Hydrophilic- attracts water
What do phospholipids form in water?
- Forms Bilayer in water
- Hydrophillic phosphate heads are arranged on outside in contact with water
- Hydrophobic fatty acid tails arranged in middle away from water
What is the test for lipids?
- Crush sample
- Add ethanol
- Shake
- Add water
- Shake
- If a lipid is present a white emulsion will be obtained
How are the properties of triglycerides useful for its function?
Insoluble in water
-Does not affect water potential of cell
-Will not dissolve and release stored energy in water
Long hydrocarbon fatty acid chains contain lots of chemical energy
-Used as energy storage molecule
How are the properties of phospholipids useful for its function?
Forms a phospholipid bilayer in water
- Forms cell membrane
- Hydrophobic fatty acid centre so water soluble molecules cannot easily pass across membrane
