2.6 Lipids Flashcards
what is a lipid (3)
- contains more energy per gram than other biological molecules
- insoluble (do not dissolve in water)
- hydrophobic
name 3 lipids and describe them
- fats and oils: energy storage molecules in organisms
- phospholipids: form membrane that separate cell from extracellular and intracellular environments
- steroids: large class of lipids that include sec hormones
what is a fat
lipid that is from animal origin solid at room temp
ex) lard, butter
what is an oil
lipid that is plant origin liquid at room temp
ex) corn oil, soybean oil
name 3 functions of fats
- long term energy storage
- insulated against heat loss
- protective cushion around major organs
what is a triglyceride
fat molecule because of three part structure; 1 glycerol molecule + 3 fatty acids
what is neutral fat
term used for triglyceride because molecule is nonpolar
what are emulsifiers
contain molecules with a nonpolar and polar end
a) describe the process of emulsification
b) name an example
a) emulsifier molecules position themselves around oil droplet so non polar ends project onwards and polar ends project outwards which causes fat/oil to disperse in water
b) washing dirty clothes w soap, salad dressing consistency (two layers and uniform consistency), fats emulsified by bile in intestines before digested, liver produces bile then stored in full bladder
what is a fatty acid
hydrocarbon chain that ends in acidic group -COOH (most fatty acids in cells contain 16 or 18 carbon atoms per molecule)
what is a FATTY
the person reading this
what is a
a) saturated fatty acid
b) unsaturated fatty acid
a) saturated: no double covalent bond accounts for solid nature of fat (lard and butter) at room temp
b) unsaturated: double bonds between carbon atoms where hydrogen is less than two per carbon accounts for liquid state of vegetable oils at room temp
what is the difference between a unsaturated cis fat and unsaturated trans fat
configuration of hydrogen atom in the double bonded unsaturated fat
a) what are trans fats
b) why is this used and where are they found
a) produced by hydrogenation (the process of chemically adding hydrogen to vegetable oils)
b) used to convert fat into solid, found in processed foods
what is a phospholipid
lipid that is constructed of 1 glycerol, 2 fatty acids, 1 phosphate group/groupings that contains phosphate and nitrogen
describe the components of a phospholipid
1 polar head: hydrophilic, soluble in water// face outwards towards water solutions
2 nonpolar tails: hydrophobic, non soluble in water// tails form hydrophobic interior
describe the function of a phospholipid in the plasma membrane
(in aqueous environment)
- form bilayer which hydrophilic head face outwards toward watery solution and tails form hydrophobic interior
- separate extracellular and intracellular environments vital to form and function of a cell
what is a steroid
lipid that has four fused carbon rings differing in the arrangements of atoms and type of functional group attached to them
a) what is cholesterol
b) what are its functions (2)
a) a steroid formed by the bush that also enters the body as part of our diet
b) 1. component of animal cell plasma membrane
2. precursor of several other steroids like bile salts, sex hormones testosterone and estrogen
why is a diet high in saturated fats, trans fats, cholesterol dangerous
can cause fatty material to accumulate inside the lining of blood vessels and reduce blood flow
what are waxes and describe its structure
lipids that protect from water loss and help energy storage in plankton
- long fatty acids attached to alcohol
- solid at roomo temperature
