Lipids Flashcards
What are triacylglycerols? What are their main function? Draw their general structure.
Triacylglycerols:
- storage lipids
- energy storage
- they store more energy than sugars, the oxidation releases more energy
- Long term storage (as opposed to glycogen)
- nonpolar - can therefore not be present in membranes
General structure: Three fatty acids (unsaturated or saturated) connected via ester bonds to a glycerol
Say the three largest classes of membrane lipids. What are their defining traits, respectively?
Phospholipids - has phosphate group attached to alcohol group
Glycolipids - has a saccharide attached to alcohol group
Archeabacterial ether lipids - unique, ‘‘double’’ structure with two alcohol groups
What are the two subclasses of phosholipids? What kind of lipid are phospholipids?
Glycerophospholipids
Sphingo (phospho)lipids
Phospholipids are membrane lipids.
What are the two subclasses of glycolipids? What kind of lipid are glycolipids?
Galactolipids
Sphingo (glyco)lipids
Glycolipids are membrane lipids.
Tell me about Glycerophospholipids.
What kind of classes do they belong to?
What are their general structure?
Glycerophospholipids are membrane lipids and phospholipids. They have a phosphate group attached to the alcohol.
Structure: Alcohol group is a glycerol. Two fatty acids + one phosphate group is attached to it. An amino alcohol is connected to the phosphate group.
What are the main functions of phospholipids?
- Reservoirs for intracellular messengers (intracellular messenger molecules can be released from them).
- Anchoring membrane proteins
Tell me about Sphingophospholipids.
What kind of classes do they belong to?
What are their general structure?
Sphingophospholipids are phospholipids and membrane lipids. They have a phosphate group attached to the alcohol.
Structure: Alcohol group is sphingosine (amino alcohol). One fatty acid and one phosphate group is attached to it. An additional group is attached to the phosphate.
If the additional group is choline or ethanol amine, the sphingophospholipid is a sphingomyelin.
Tell me about Galactolipides.
What kind of classes do they belong to?
What are their general structure?
What are the galactolipides called if a sulfate group is attached to the saccharide?
They belong to the glycolipids and the membrane lipids.
Structure: Alcohol group is a glycerol. Two fatty acids and a mono/di-saccharide is attached to the glycerol.
If a sulfate group is attached to the saccharide, it is a sulfolipid.
What is sphingosine?
An amino alcohol.
Tell me about Sphingoglycolipids.
What kind of classes do they belong to?
What are their general structure?
They belong to the glycolipids (has saccharide attached to alcohol) and the membrane lipids.
Structure: Alcohol group is a sphingosine. One fatty acid is connected to the alcohol, as well as one mono/oligosaccharide.
What are the three subclasses of Sphingoglycolipids?
Cerebrosides
Globosides
Gangliosides
What are the main functions of Sphingoglycolipids?
They are recognition sites on cell surfaces, can act like antigens for the immune system.
Determines human blood groups through an additional saccharide attached.
What kind of lipid are Sterols?
Membrane lipids
What is characteristic for sterols? Give an example of sterol.
They have a unique structure of 4 fused rings.
They can act as hormone precursors.
Cholesterol.
What are waxes? What class does the waxes belong to?
Waxes are storage lipids. Unlike triacylglycerols, they are quite firm and solid.
Very high in energy.
They have higher melting points than triacylglycerols.
Can be used as water repellents of different sorts, ex. the fatty feathers of ducks, the wax layer on plant leaves.
