Chapter 3.4.2 (Exam 1) Fatty Acids Flashcards
Lipids Are Defined by Their Insolubility in Water
What are the two types of fatty acids?
Saturated fatty acids
Unsaturated fatty acids
Describe saturated fatty acids.
No double bonds between carbons—it is saturated with H atoms
i.e. animal fats; solid at room temperature
Describe unsaturated fatty acids.
One or more double bonds in the carbon chain result in kinks that prevent packing
i.e. plant oils; liquid at room temperature
What are the two types of unsaturated fatty acids?
Cis-unsaturated fatty acids
Trans-unsaturated fatty acids
Describe cis-unsaturated fatty acids.
Double bonds in naturally occurring unsaturated fats are cis
H atoms are on the same side creating a “kink” or bend in the carbon chain
Describe trans-unsaturated fatty acids.
H atoms are on opposite sides of the C=C bond
Having the H atoms on opposite sides removes the “kink” from the structure
How are trans fats created?
Trans fats result from hydrogenation of vegetable oils to produce a saturated fat (e.g. for margarine), but some of the cis bonds convert to trans
The hydrogenation process straightens out carbon chain; when hydrogen atoms are flattened on the same side, their electron clouds pushing against each other makes them reform on opposite sides
Why are trans fats bad for your health?
Trans fats may contribute to heart disease and stroke
What is the function of omega-3 fatty acids against trans fats?
Omega-3 fatty acids protect against heart disease and stroke
Why are they called omega-3 fatty acids?
The first C=C bond is at position 3 in the fatty acid chain
Where would you find the 1st double bond in an omega-6 fatty acid?
At the 6th carbon
What are phospholipids?
Fatty acids bound to glycerol; a phosphate group replaces one fatty acid
Phospholipids are amphipathic. What does it mean to be amphipathic?
“Head” is a phosphate group—hydrophilic
“Tails” are fatty acid chains—hydrophobic
What is a phospholipid bilayer?
In water, phospholipids line up with the hydrophobic tails together and the phosphate heads facing outward
Where is the phospholipid bilayer structure found in nature?
Biological membranes
What are lipoproteins in animals?
Lipoproteins in animals are formed from phospholipids and proteins, and they work to transport lipids such as cholesterol in the blood
What are carotenoids?
light-absorbing pigments, e.g.,
β-carotene
What is the function of the carotenoid β-carotene?
β-carotene traps light energy for photosynthesis
In humans, β-carotene breaks down into Vitamin A
What are steroids? What is one important example of a steroid?
Multiple rings share carbons
Cholesterol is important in membranes; other steroids are hormones
What are waxes? Where is wax found in nature?
long-chain alcohol bound to a saturated fatty acid
beeswax; waxy cuticle on leaves
