Lipids and Fatty Acids Flashcards
What is the only thing lipids are soluble in?
Only soluble in non-polar solvents
Are fatty acids, hydrophobic or hydrophilic?
2
They are amphiphilic
But the hydrocarbon chain generally makes them act hydrophobic
What are the three main functions of lipids in the body?
Energy storage
Cellular signalling
Cellular structural components
Describe the structure of a fatty acid?
A carboxylic acid (COOH) joined to a long hydro-carbon chain
What is formed when fatty acids undergo saponification?
Soap and glycerol
What are the two classifications of fatty acids?
Saturated fats
Unsaturated fats
What is a mono-unsaturated fatty acid?
One carbon-carbon double bond is present
What is a poly-unsaturated fatty acid?
Two or more carbon-carbon double bonds are present
How can unsaturated fats be subcategorised?
By the type of double bond present (cis or trans)
Write a note on trans fatty acids.
4
Increase amount of LDL
Reduce amount of HDL
Naturally occurring, higher levels in processed foods
Found in butter, milk, ground beef etc
Write a note on cis fatty acids.
5
Increase amount of HDL
Naturally occurring
Hydrogenated during food processing to form a saturated fat
Isomerisation during processing to form a trans fat
Found in olive oil, vegetable oil, avocado etc
How are fatty acids named symbolically?
x:y ^(Da, b, c)
x = number of Cs in chain
y = number of double bonds
a, b, c are the position of double bonds counting from C1 at the carboxyl end
What is the x in the symbolic naming of fatty acids?
The number of Cs in the chain
What is the y in the symbolic naming of fatty acids?
The number of double bonds in the chain
What is the a, b, c in the symbolic naming of fatty acids?
The position of double bonds counting from C1 at the carboxyl end
What are the four most common omega acids?
Omega-3
Omega-6
Omega-7
Omega-9
How are omega acids named?
3
Omega means its unsaturated
The number tells you where the double bond is
Count back from the last carbon on the hydrocarbon chain
What are triacylglycerides?
2
Molecules that contain one glycerol group and three fatty acid chains joined by an ester bond
Very hydrophobic
Where does the ester bond of TAGs form?
They form at the interface between an OH group on the glycerol and the carboxylic acid of the fatty acid
What is a glycerol?
A 3 carbon sugar alcohol
Give three characteristics of glycerol.
Odourless
Colourless
Slight sweet taste
Give a use of glycerol.
Used as a bulking agent in many products
How many fatty acids can a glycerol bind?
Three
What physical change takes place when an unsaturated fatty acid is hydrogenated?
An oil becomes a solid
What are waxes?
2
Chemically heterogenous group of compounds
Formed by an Ester which combines a long chain fatty acid and a long chain alcohol
Write a note on waxes.
4
Found in both animals and plants
Prevent water loss and protection from pests in plants
Generate a water proof coating in animals
Used in candles, car waxes, cosmetics etc
What are membrane lipids/phosphoglycerides?
2
Highly variable between tissues and cells
General structure consists of a glycerol 3-phosphate molecule joined with 2 fatty acids
What 2 fatty acids join the glycerol 3-phosphate molecule?
A saturated C16 or a saturated C18 fatty acid at C1
An unsaturated C18-20 fatty acid at C2
How is a phosphoglyceride named?
Based on what is attached at the head group substituent of the phosphate group
Phosphatidyl-X
What are the two most common phosphoglycerides?
Ethanolamine containing
Choline containing
Write a note on phosphatidylethanolamine.
3
Found on the inner leaflet of the plasma membrane
Important to heart health
Plays a part in blood clotting
Write a note on phosphatidylcholine.
4
Found on the outer leaflet of the plasma membrane
Found in nearly every cell of the body
Important in the central nervous system
Commercial use as an emulsifying agent
What are plasmalogens?
A specific class of phosphoglyceride, which contain an ether linked alkenyl chain at the C1 position
Give an example of a plasmalogen.
Platelet Activating Factor
PAF
What does PAF do?
2
Signals for the aggregation of platelets at the site of injury
Has a role in inflammation and in allergic reactions
What are sphingolipids?
4
Based on a 3 carbon backbone. similar to glycerol
Sphingosine added at the C3 position
Fatty acid bound at C2 position (16,18,22 or 24 carbons - sat or unsat)
Ceramide or ceramide derivative at the C1
What is sphingosine?
A long chain amino alcohol
What are glycosphingolipids?
They define your blood type
What are the five different types of fatty acids?
Triacylglycerols
Waxes
Glycerophopholipids
Sphingolipids
Glycosphingolipids
