Chapter 11 Flashcards
What are the 5 classes of lipids?
- Free fatty acids: common fuel.
- Triacylglycerols: storage form of fatty aicds.
- Phospholipids: membrane lipids.
- Glycolipids: membrane lipids composed in part of carbohydrates.
- Steroids: polycyclic hydrocarbons with a variety of functions.
What are 2 types of fatty acids?
Palmitate: ionized form of palmitic acid.
Oleate: ionized form of oleic acid.
What are shapes of saturated and unsaturated fatty acids?
13 carbon atoms, 21 carbon atoms, 12 carbon atoms, 20 carbon atoms, and 22 carbon atoms.
How are fatty acid carbon atoms numbered?
Fatty acid carbon atoms are usually numbered beginning with the carboxyl terminal carbon atom.
Carbon atoms 2 and 3 are also referred to as alpha and beta, respectively.
Fatty acids can also be numbered from the methyl carbon atom, which is called the omega (w) carbon.
What are important w-3 fatty acids.
Cis polyunsaturated fatty acids are essential components of our diets because humans cannot synthesize them.
These fatty acids are precursors to a variety of hormones and appear to offer some protection from coronary heart disease.
alpha-Linolenate, Eicosapentaenoate (EPA), Docosahexaenoate (DHA).
Explain how fatty acids vary in chain length and degree of unsaturation.
Properties of fatty acids are dependent on chain length and degree of unsaturation. Short chain length and the presence of cis double bonds enhances the fluidity of fatty acids.
Palmitate:
- 16 carbon atoms.
- 0 double bonds.
- n-Hexadecanoate.
- CH3(CH2)14COO-.
Stearate:
- 18 carbon atoms.
- 0 double bonds.
- n-Octadecanoate.
- CH3(CH2)16COO-.
Oleate:
- 18 carbon atoms.
- 1 double bond.
- cis-delta9-Octadecenoate.
- CH3(CH2)7CH=CH(CH2)7COO-
Explain melting point and double bonds.
Saturated fatty acids pack in a fairly orderly way.
Unsaturated cis fatty acids pack less orderly due to the kink.
It takes less thermal energy to disrupt disordered packing of unsaturated fatty acids.
- Unsaturated cis fatty acids have a lower melting point.
What does solubility do to fatty acids.
Decreases as the chain length increases.
What does the melting point do to fatty acids.
Decreases as the chain length decreases.
Decreases as the number of double bonds increases.`
How do fatty acids produce triacylglycerols?
React with glycerol.
3 fatty acid chains are bound to glycerol by dehydration synthesis.
Why are triacylglycerols the storage form of fatty acids?
Majority of fatty acids in biological systems are found in the form of triacylglycerols.
- Solid ones are called fats.
- Liquid ones are called oils.
Less soluble in water than fatty acids due to the esterification of the carboxylate group.
Talk about how the major site for triacylglycerol storage in mammals is adipose tissue.
Each adipocyte (adipose cell or fat cell) contains a large lipid droplet, in which the triacylglycerols are houses.
Lipid droplets have important functions beyond energy homeostasis.
Store vitamins, signaling precursors, and other hydrophobic molecules.
Mitigate some harmful effects of ER and oxidative stress.
Function in protein maturation, storage, and turnover.
Motile and can exist in the nucleus.
Also serves as a thermal insulator.
Migrating birds may not eat during long flights. They get energy from fatty acids derived from triacylglycerols stored.
What are the 3 common types of membrane lipids?
- Phospholipids.
- Glycolipids.
- Cholesterol.
What are phospholipids?
The major class of membrane lipids.
Composed of 4 components: fatty acids (1 or more), platform to which the fatty acids are attached, phosphate, and alcohol.
Two common platforms are glycerol and sphingosine (more complexed alcohol).
Phospholipids with a glycerol platform are called phosphoglycerides or phosphoglycerols.
Talk about some common phosphoglycerides found in membranes.
Highly polar phosphate group may be further esterified by an alcohol; such substituent groups are called the head groups.
Common alcohols are serine, ethanolamine, choline, inositol, and glycerol.
