5.1 Structural Lipids Flashcards
1
Q
Lipids
A
- serving vital structural, signaling, and energy storage roles
- can be an important part of
processes like cell recognition and signaling
2
Q
Amphipathic
A
- has both hydrophilic and hydrophobic regions
- fatty acid tails are the hydrophobic region
3
Q
Phospholipids
A
- contain: a phosphate and alcohol that comprise the polar head group, joined to a hydrophobic fatty acid tail by phosphodiester linkages
- One or more fatty acids are attached to a backbone to form the hydrophobic tail region
4
Q
How’re lipid properties determined?
A
- by the degree of saturation in fatty acid chains and the functional groups to which the fatty acid chains are bonded
5
Q
What 2 properties determine how the molecule will behave?
A
- Saturation and length
6
Q
Why’re saturated fatty acids more stable?
A
- Have greater van der Waals forces
7
Q
Glycerophospholipids
(or phosphoglycerides)
A
- phospholipids that contain a
glycerol backbone bonded by ester linkages to two fatty acids and by a phosphodiester linkage to a highly polar head group
8
Q
Why are head groups on lipids important?
A
- the head group determines the membrane surface properties
- glycerophospholipids are named according to their head group
- can be positively charged, negatively charged, or neutral
- very important to cell recognition, signaling, and binding
9
Q
Sphingolipids
A
- have a sphingosine or sphingoid (sphingosine-like) backbone
- have long-chain, nonpolar fatty acid tails and polar head groups
- sites of biological recognition at the cell surface and can be bonded to various head groups and fatty acids
- Most contain contain a phosphodiester linkage, others contain glycosidic linkages to sugars
- Ex: cell surface antigens of RBCS
10
Q
What’re the 4 major subclasses of Sphingolipids?
A
- Simplest sphingolipid is ceramide (has a single hydrogen atom as its head group)
- Sphingomyelins are the major class of sphingolipids and are also phospholipids
_major components in the plasma membranes of cells producing myelin
_have no net charge - glycosphingolipids are found mainly on the outer surface of the plasma membrane and can be further classified as cerebrosides (have single sugar) or globosides (have two or more sugars)
- Gangliosides are glycolipids that have polar head groups composed of oligosaccharides with one or more N acetylneuraminic acid (NANA; also called sialic acid) molecules at the terminus and a negative charge
_play a major role in cell interaction, recognition, and signal transduction.
11
Q
Waxes
A
- esters of long-chain fatty acids with long-chain alcohols
- they form pliable solids at room temperature (wax)