Lipids Flashcards
Plasmalogens
Contain unsaturated fatty alcohol not fatty acids in position 1. Are bonded to carbon 1 of glycerol, through ether bonds. Ethanolamine is found in hydrophilic head of plasmalogens
Cardiolipin
Complex molecule of fatty acids, 3 molecules of glycerol, and 2 phosphate ions. Is formed when phosphoridate esterifies through phosphate group to glycerol. Is an important component of inner mitochondrial and some bacterial membrane. Only glyceropospholipid that is antigenic
Phospholipids
Ampiphatic, non polar aliphatic hydrocarbon tail and polar phosphoryl-x head.
Polar head is arranged outward, non polar tail stays inward and interact with other non polar comps of membrane eg glycolipids,SOME protein, cholesterol
Constitutes majority of biological membrane
Are further divided into:
a. Phosphoglycerols
b. Sphingomyelin
Phosphoglyceride
Are ampiphatic.
Phosphotidate has a similar structure with triacylglycerol.
It is formed when carbon 1&2 esterify with fatty acid, but 3rd one esterifies with phosphate group.
Phosphotidate is rare in free form, and not a major lipid constituent of biological membranes, but aids in derivation of others.
Polar head group consists of + charged alcohol group and - charged phosphate group.
2 molecules of fatty acid forms 2 tails.
Alcohol comps of head can be ethanolamine, serine,choline, etc
Less common examps of phosphoglyceride is cardiolipin and plasmalogens.
Importance of phospholipids
- Biological detergents
- Surfactant
- Make up.biological membrane
- Anchor protein to molecules
Glycolipids
The second type of phospholipids. It is formed when carbohydrate attaches itself to ceramide. Has sphingose backbone
Another name for glycolipids
Glycosphingolipids
Types of glycolipids
They are classified based on nature of carbohydrate component, as follows:
1. Cerebrosides
2. Sulphatides
3. Gangliosides
4. Globosides
____________is the most common cerebroside found in membranes
Galactocerebrosides
What is glucocerebroside’s primary function
Serves as an intermediate in synthesis and degradation of more complex glycolipids
What differentiates cerebrosides
The type of fatty acid in them
What type of fatty acid is MOSTLY found in cerebrosides, with examples
C 24 fatty acid eg:
Lyngoceric acid
Nervonic acid
Oxynervonic acid
Cerebronic acid
The C 24 fatty acid Makes up specific cerebrosides namely
Kerasin
Nervon
Oxynervon
Cerebron
Cerebrosides
Formed when monosaccharides are attached to ceramides, mainly glucose and galactose
Sulphatides
Sulphuric acid esters of galactocerebrosides.
Where are sulphatides majorly found in
Nervous tissue
Globosides
Oligosaccharide chain is attached to ceramide
Gangliosides
An oligosaccharide chain( with sialic acid) attached to ceramide
Where are gangliosides found?
At ganglions of CNS, PARTICULARLY at nerve endings
Sialic acid
Also called N- Acetylneuraminic acid (NANA).
An acid sugar that occupies terminal positions of Oligosaccharide chain of gangliosides.
Classification of gangliosides
- Based on no of NANA molecules
- Based on length of molecules (sequence)
Based on no of NANA molecules, They’re classified into:
GM one molecule
GD two …
GT three …
GQ Four…
Based on sequence
GM 1 (longest and most sluggish in thin layer chromatography paper)
GM 2
GM 3 (shortest)
The numbers are gotten based on relative movement on thin layer chromatography paper
Importance/ biological functions of glycolipids
- They constitute cell membrane (although they’re less abundant than phosphoglycerides).
Max density/ conc is in plasma membrane BUT max no is in nervous tissues. - Sphingolipids are antigenic, help in cell to cell interaction, growth and development.
- Gangliosides r receptors for toxic agents and pathogens like vibrio cholerae, influenza virus, etc.
