lipids Flashcards
(19 cards)
what are the main characteristics of lipids?
-insoluble in water
-hydrophobic (lots of C-H bonds)
-do not form polymers
name the 3 families of lipids
-triglycerides
-phospholipids
-steroids
describe triglycerides and their function
-made up of one glycerol and 3 fatty acids
-C-H bonds serve as long-term energy storage
what is the name of the bond that links the fatty acid chain to the glycerol?
ester linkage
what are saturated triglycerides?
-no pi bonds
-they have a higher melting point
-animal origin
what are unsaturated triglycerides?
-1+ pi bonds
-low melting point
-plant origin
what are monounsaturated fatty acids and polyunsaturated fatty acids
-monounsaturated = one double bond
-polyunsaturated = more than one double bond
true or false: cis fatty acids are the most naturally occurring unsaturated fatty acids
true
true or false: trans fatty acids are associated with bad cholesterol and an increased risk of coronary heart disease
true
which molecule composes the outer and inner membranes of cells?
phospholipids
what are phospholipids composed of?
-a phosphate group (head)
-glycerol
-2 fatty acids (tails)
phospholipids are amphipathic, what does it mean?
they are both hydrophilic (head) and hydrophobic (tails)
what are micelles?
they are lipid molecules with polar head oriented towards the water and the non-polar tails away from the water
what is the consequence of there being unsaturated fatty acids in the tails of phospholipids?
-creates kink in the fatty acid tails
-less packing between fatty acid tails which makes the plasma membrane fluid
what are steroids composed of?
4 carbon rings
what is the function of steroids?
-chemical signaling (hormone)
-fluidity of the plasma membrane (cholesterol)
why does membrane fluidity increase at lower temperature?
so the plasma membrane does not solidity
what are oligosaccharides?
3 to 10 monosaccharides linked together
what is the function of oligosaccharides?
they are found on cell surfaces acting as identification markers
