Lipids & Lipid Catabolism Flashcards
Most fatty acids are __ to __ carbons in length.
16; 18
Most fatty acids have an [even/odd] number of carbons.
even
The majority of fatty acids in plants and animals are ______.
unsaturated (Often polyunsaturated/PUFAs)
The first double bond is usually between carbon __ and carbon __.
9; 10
In PUFAs, are double bonds conjugated or not?
Not conjugated
Fatty acid double bonds are almost always [cis/trans], giving them a rigid __º bend.
cis; 30
Melting point [increases/decreases] with chain length and [increases/decreases] with unsaturation/double bonds.
increases; decreases
The oxidation of fatty acids to ___ and ___ is highly [endergonic/exergonic].
CO2; H2O; exergonic
What is the chemical formula for fatty acids?
CH3(CH2)nCOOH
What’s the difference between saturated and unsaturated fatty acids?
Saturated: No double bonds
Unsaturated: Contains at least one double bond
Where is the alpha carbon in a fatty acid?
Next to C1, the carboxylate carbon
For PUFAs, C1 is assigned to the _____ _____ _____, and it’s also designated __.
terminal methyl carbon, omega (ω)
Cis double bonds restricts _____ and causes a _____ in the hydrocarbon tail.
rotation; bend
Saturated fatty acids pack into ______ ______.
crystalline arrays
Glycerol and fatty acids are esterified to generate a _______.
triacylglycerol/triglycerides
What are the two advantages that triglycerides (as storage forms of energy) have over polysaccharides?
- More reduced than carbohydrates, so contain 2x as much energy per gram
- Since hydrophobic, don’t need to carry the weight of water necessary for hydration
Trans fats make oils ____ at room temperature.
solid
Why are trans fats bad for you?
- Increased risk of heart disease
- Increases LDL (bad) cholesterol
- Lowers HDL (good) cholesterol
Trans fatty acids are _____, making their melting points [higher/lower] than those with cis bonds.
linear; higher
Lipid bilayers are amphipathic. What does this mean?
They have both polar/hydrophilic and non-polar/hydrophobic regions.
What model is used to illustrate membrane structure? What does it look like?
Fluid mosaic model
Integral proteins float in this sea of lipid.
Proteins and lipids are free to move laterally in the plane of the bilayer.
(Movement from one leaflet of the bilayer to the other is restricted)
Why do lipid bilayers form?
Each lipid molecule has a very hydrophobic tail, which forces surrounding H2O molecules to become highly ordered.
This goes against the second law of thermodynamics, which says that the entropy of an isolated system not in equilibrium will tend to increase over time (become more random).
Clusters of lipid molecules and micelles increase entropy. Why?
Only lipid portions at the edge of the cluster force the ordering of water. Fewer H2O molecules are ordered.
All hydrophobic groups are concealed from water in micelles.
Steroid hormones are [slow/fast]-acting, and they effect gene expression by doing what?
slow; activating nuclear receptors
