Lipids Flashcards
What are lipids?
Macromolecule (NOT polymers) which are only soluble in organic solvents such as alcohols
What is the structure of lipids?
Glycerol + fatty acids
Draw the structure of a glycerol molecule
-correct drawing
Draw the structure of a fatty acid-
- correct drawing
Features of a saturated fatty acid-
-saturated with hydrogen atoms
-no c=c double bonds
Features of unsaturated fatty acids?
-less saturated with hydrogen atoms
-1 or more c=c double bonds which cause kinks in the chain
Why are UFA more fluid and have smaller boiling point that SFA
The kinks in the chain push the molecules apart slightly
Why are all fatty acids insoluble in water?
They are non-polar molecule and cannot form hydrogen bonds in the water
Draw the bonding of a glycerol molecule with one fatty acid
-correct drawing
What is a triglyceride?
One glycerol and three fatty acids
What type of reaction makes a triglyceride? What reaction to break it apart?
-Condensation
-Hydrolysis
Bond formed in a triglyceride?
Ester bond
What are the 5 functions of triglycerides?
1) Energy source
2)energy store
3)insulation
4)buoyancy
5)protection
How are triglycerides a good energy source?
-broken down in respiration to release atp
-ester bond in a hydrolysed and glycerol and fatty acids are broken down into CO2 and water
How are triglyceride a good energy store?
-insoluble= can be stored without affecting water potential
-mammals store under skin
-lipids have more H atoms than carbohydrates so they can release more energy per gram
How are triglycerides good insulators?
-lipids in nerve cells act as electrical insulator
-animals store an extra layer of fat in preparation for hibernation
How do triglycerides help with buoyancy?
-fat less dense than water, helps aquatic animals to float
How are triglycerides good for protection?
-fat around delicate organs absorbs shock
-peptidoglycan wall of some bacteria covered in a lipid-rich outer coat
What is a phospholipid?
Similar to a triglyceride except one fatty acids is replaced with a phosphate group
Draw a phospholipid-
-correct drawing
Which parts of the phospholipids are polar and attracted to water and which parts aren’t?
-The phosphate group has a negative charge making it polar and hydrophilic
-the fatty acids tails are non polar and hydrophobic
Which parts of the phospholipids are polar and attracted to water and which parts aren’t?
-The phosphate group has a negative charge making it polar and hydrophilic
-the fatty acids tails are non polar and hydrophobic
What is a phospholipid monolayer?
Layer of phospholipids on the surface of water with heads sticking into the water and fatty acids tails sticking up out of the water.
What is a phospholipid bilayer?
Two rows of phospholipids with tails point inwards and heads pointing out.
-typically for membranes around cells and organelle
What is a phospholipid Micelle?
Balls with tails inside and head on the outside
What is a phospholipid Micelle?
Balls with tails inside and head on the outside
Phospholipids are found in membranes, name their functions-
-fluidity= individual phospholipids are able to move around in their layer
-stability= they will not move to a position that exposes their tails to water
-selectively permeable= only small non-polar molecules can move through the bilayer (Oxygen and CO2)
What is cholesterol?
-A lipid made from 4 carbon based rings instead of glycerol and fatty acids
-it is small and hydrophobic
Functions of cholesterol?
-Membrane fluidity= sits between hydrophobic fatty acid chains, keeps it fluid at low temps and prevents it becoming too fluid at high temps
-used to produce steroid based hormones
