1.2 Lipids Flashcards
What are lipids composed of?
Carbon, hydrogen, some oxygen
What kind of molecules are lipids
Non polar
What is a triglyceride composed of ?
One molecule of glycerol and three fatty acids.
What kind of reaction forms a triglyceride?
Condensation reaction
What is a condensation reaction?
When two hydrogen atoms and one oxygen atom is removed to join two things
What kind of bond joins the glycerol molecule and fatty acid chain ?
Ester bond
What is an ester bond ?
Covalent bond formed via condensation reaction between -OH group of a carboxylic acid and an -OH group of an alcohol
How is the triglyceride synthesised ?
- Condensation reaction happens between OH- group of carboxlyic acid and OH- group of fatty acid to remove 2 hydrogen and one oxygen which then forms a covalent ester bond between the two
What kind of reactions break down a triglyceride ?
Hydrolysis
How does a hydrolysis reaction break down the triglyceride?
By adding three water molecules which were previously taken out to then separate glycerol and three fatty acid chains
What are triglycerides in general and where can you find them?
A good source of energy, oils butter
What are the purposes of phospholipids in an organism ?
- To provide structural role in cell membranes
What differentiates unsaturated and saturated fatty acids?
The presence of double carbon bonds in the fatty acid tails
Why are some fatty acids saturated?
Fatty acids with hydrocarbon chains that have no double bonds between carbon atoms are saturated
Why are some fatty acids unsaturated ?
Fatty acids with one or more double bonds between two carbon atoms make the fatty acid unsaturated
What structural change is caused due to the double bond in unsaturated fatty acids and what does this do ?
- Bends in the fatty acid tail which pushes the molecules further apart from each other than saturated molecules
What do the bends then cause ?
Reduces intramolecular forces between the triglycerides so they form a liquid at room temp
Why are triglycerides a good energy store?
1 - They provide the most energy per unit of mass of any storage molecule, this is useful as it reduces the mass that must be carried around
Why are triglycerides water insoluble, why is this important ?
They are large and non polar therefore insoluble. This is important because they do not affect the osmotic balance of cells in the body
What is another purpose of triglycerides?
- They can be used as a fat store for insulation
What is the difference between a phospholipid and a triglyceride?
- In the phospholipid one of the fatty acids is replaced via a phosphate molecule which is attached to glycerol
- How does the phosphate group bind to the glycerol
Via a condensation reaction between the OH groups of phosphoric acid and glycerol to remove water and join the two via cov bond
The phospholipid head is ?
Hydrophillic due to negative charge
What does hydrophillic
Molecule attracted to water due to charge
The fatty acid tails on a phospholipid are ?
HYDROPHOBIC
Why are they hydrophboic
- They do not have any charge therefore repel water
How do phospholipid bi layers remain fluid ?
Because they can move past and thru each other.
What are the roles of phospholipids in cells?
- ## Controls substances in and out of the cell.
How can a gene mutation result in an enzyme not being able to digest a lipids (5)
- Change in the DNA sequence
- Change in the primary structure of a protein due to different R groups
- This then leads to different type of bonding
- This then changes the way the protein is folded into its 3D structure
- This causes a change in the active site therefore lipid does not fit in active sit as a substrate anymore
What are two dietary factors which cause CVD
High saturated fats
High alcohol intake
