Lipids Flashcards
Lipids are used as a…
Principal form of storing energy
Lipids are ____ in water
Insoluble
Where are lipids found?
Membranes
Major structural elements of biological membranes
Fatty acids
Hydrocarbon derivatives
Stored form of energy
Low oxidation state
Carboxylic acid + hydrocarbon chain
Saturated vs unsaturated
Saturated: single bonds
Unsaturated: double bonds
What changes melting point (fatty acids)?
Increase mp:
- single bonds (saturated)
- long hydrocarbon chains
Decrease mp:
- double bonds (unsaturated)
- short hydrocarbon chains
Solubility of fatty acids in water
Low solubility:
- longer fatty acid chain (non polar)
- less double bonds
High solubility:
- short chains
- more double bonds
Triacylglycerols
3 fatty acids + 1 glycerol
Store energy (adipose)
Insulation
Lipases catalyze the hydrolysis of triacylglycerols
Lipases
Enzymes that catalyze the hydrolysis of triacyglycerols
Releasing fatty acids for export to sites that require fuel
What is more common in fatty acids, cis or trans double bonds?
Cis
Waxes
Esters of long chain fatty acids and long chain alcohols
Energy stores
Water repellent
Higher mp
Two back bones of lipids
Glycerol
Sphingosine
Glycerophospholipids
Fatty acids eateries to two of the hydroxyl groups of glycerol
Head group (alcohol) eateries to third hydroxyl group of glycerol
Via phosphodiester bonds
What do glycerophospholipids have many of?
Many head groups
Sphingolipids
Sphingosine + long chain aliphatic amino alcohol + 2 hydrocarbon chains
No glycerol
Important for RED BLOOD CELLS
Sterols
Four fused rings + hydroxyl group (polar head)
Cholesterol:
- membrane component
- Precursor to steroids
Types of phospholipids
Glycerophospholipids
Sphingolipids
lipid nomenclature convention
the chain length : number of double bonds
18:1
where are phospholipids and sphingolipids degraded?
lysosomes
PUFAs
polyunsaturated fatty acids
omega-3/6 fatty acids
double bond on 3rd carbon and 6th carbon
cis vs trans fatty acids
polar lipids (2)
glycerophospholipids
sterols
In saturated fatty acids, the carbons are linked exclusively by single bonds. Monounsaturated fatty acids have one carbon-carbon double bond and polyunsaturated fatty acids have more than one.
A. Both statements are true
B. Both statements are false
C. First statement is true and second is false
D. First statement is false and second is true
A
The molecule pictured below plays a major role as an:
A. Energy source
B. Membrane component
C. Signal mechanism
D. Two of the above
E. All of the above
A. energy source
B. membrane componentt
?
- triacylglycerol
- hydrophilic: glycerol polar head
- hydrophobic: carbon non-polar tails
- 18:3 (delta 9, 12,15) OR omega-3 (w-3)
- 22:6 (delta 4, 7, 10, 13, 16, 19) OR omega-3 (w-3)
- 20:4 (delta 5, 8, 11, 14)
MP rank (high to low)
1.
only three double bonds (less double bonds = increase mp)
short c chain (decreases mp)
- six double bonds (more double bonds = decrease mp)
long c chain = increases mp
* lowest mp - four double bonds
long c chain = increase mp
Increase mp:
- single bonds (saturated)
- long hydrocarbon chains
Decrease mp:
- double bonds (unsaturated)
- short hydrocarbon chains
