lipids Flashcards
give the 4 types of lipids
triglycerides, phospholipids, steroids, waxes
are lipids defined in terms of solubility or structure
solubility
why are lipids insoluble in water?
they lack a polar head
what are the 4 functions of lipids
energy storage as adipose tissue, insulation + protection, component of cell membranes, intercellular messages
where can lipids be found in the nervous system
myelin sheath
give some organismal uses of fats, oils, phospholipid, steroids and waxes
fats: long term energy storage + insulation in animals, oils: long term energy storage + insulation in plants, phospholipid: component of plasma membrane, steroids: hormones + plasma membrane, waxes: myelin sheath, wear resistance, retain water
describe the structure of a saturated fatty acid
no double bonds between the carbon atoms, straight chains, chains can be packed together (lie flat) in adipose tissue
describe the structure of a glycerol
a three carbon compound with three hydroxyl groups
is glycerol soluble in water
yes- it has polar hydroxyl groups
what sort of bond joins lipids together
ester bonds
how is a fat formed
via a condensation dehydration reaction between the acid portion of three fatty acids and the hydroxyl groups of glycerol
why are fats and oils often called trigylcerides
the presence of three fatty acids and one glycerol
is animal fat solid or liquid at room temp
solid
is plant fat solid or liquid at room temp
liquid
how are triglycerides generally used in plants and animals
long term storage
describe the structure of a wax
a long chain of fatty acids bonded with a long chain alcohol
what is the function of a wax
protection- ie waxy cuticle on leaves or ear wax in humans and animals
do waxes have a high or low melting point
high
what is the main function of phospholipids
they form the core of all biological membranes
what is an individual phospholipid made of
glycerol, 2 fatty acids and a phosphate group
what are phospholipids derived from
triglycerides
are the fatty acids in phospholipids polar or non polar
non polar
is the phosphate group in phospholipids polar or non polar
polar
what part of the phospholipid determines the surface properties of membranes
the head groups
what is in the basic structure of a steroid
4 fused carbon rings
what is the precursor steroid for many other steroids
cholesterol
how do steroids differ primarily from each other
the types of functional groups
