Lipids Flashcards
Define: Lipids
Naturally occurring nonpolar molecules
Can only dissolve in nonpolar organic solvents.
Monomer of: Lipid
Fatty acid
- Unsaturated fatty acid
- Saturated fatty acid
Functional Group of: Lipid
Hydrocarbon chain + Acid (COOH)
(O= & H-)C-C-C-C-H + ‘saturated’ w/H or ‘unsaturated’ w/H w/C=C bond
Types of Lipids
- Unsaturated fatty acid
- Saturated fatty acid
- Steroids
- Phospholipids
Lipid Functions
- long-term energy storage
- insulation against heat loss
- protection of major organs
- phospholipid bilayer to protect cell
- component of steroid hormones and sex hormones
Fats
- usually of animal origin
- solid @ room temp
- composed of saturated fatty acids
Oils
- usually of plant origin
- liquid @ room temp
- composed of unsaturated fatty acids
Saturated Fatty Acids
- usually from animals
- solid @ room temp
- ‘saturated’ w/H
(O= & H-)C-C-C-C-H + H single bonds to C’s
-straight
Unsaturated Fatty Acids
- usually from plants
- liquid @ room temp
- ‘unsaturated’ w/H
- double covalent bonds btwn C’s that hold less than 2 H’s
(O= & H-)C-C=C-C-H + H single bonds to single bond C’s
-are bent
Polymer of: Lipid
Triglyceride
- neutral fat bc the molecule is nonpolar
- cannot absorb them; must be hydrolyzed
How to form a Triglyceride
1 glycerol + 3 fatty acids = 1 triglyceride + 3 H2O (dehydration reaction)
Emulsification
Process of breaking up fat globules into smaller droplets by using emulsifiers.
Tails attach to fat and polar heads face outward to polar substance and pulls the fat apart in this interaction/reaction.
Allows fat globules to be moved within water (not just sit on top).
Emulsifiers
Polar head group + nonpolar fatty acid tail
What is the body’s emulsifier?
Bile
- produced in liver & stored in gall bladder
- gall bladder releases bile into the small intestine onto chyme
- if gall bladder removed the liver will produce bile on demand
Omega-3 Fatty Acid
- polyunsaturated fatty acid essential to human health
- necessary for brain function/development
- lowers cholesterol levels
Omega-6 Fatty Acid
- polyunsaturated fatty acid essential to human health
- essential for human body development but over-consumed in Western diet
- too much = heart disease, too little = ADD/ADHD
Omega-9 Fatty Acid
- unsaturated fatty acid
- not essential for human health
- linked to reducing cholesterol levels
- used for treatment purposes
Hydrogenation
Process of changing the structure of an unsaturated fatty acid to having the structure of a saturated fatty acid.
“Adds Hydrogen” by heating unsaturated fat, breaking the C=C to C-C + H’s
Unsaturated fats now solid @ room temp
Trans Fat
- Fatty acids affected by hyrogenation
- considered synthetic since they don’t occur naturally
- often found in food to preserve them and increase taste
Phospholipid
1 Phosphate group (hydrophilic) + 2 Fatty acid chains as nonpolar tails (hydrophobic)
Hydrophilic
Substances are polar + water-loving
Hydrophobic
Substances are nonpolar + water-repelling
Phospholipid Functions
- form the membrane of a cell
- phospholipid bilayer: polar heads facing out & nonpolar tails facing in
- helps to separate the extra cellular material from inter cellular material
Steroids
- all steroids have 4 fused carbon rings
- differ by arrangement of atoms + attachment of functional group
- cholesterol
- estrogen
- testosterone
