Section 4 - Carbohydrates and Lipids
Chapter 11 - Lipids
● Lipids: water-insoluble molecules that are highly soluble in organic solvents
○ Store energy, key components of membranes, signal-transduction pathways
○ 5 classes
■ Free fatty acids (nonesterified fatty acids)
● Fuel and components of membrane lipids
● Vary in hydrocarbon chain length
■ Triacylglycerols
● The storage form of fatty acids
■ Phospholipids
● Consist of fatty acids attached to a scaffold that also bears a
charged phosphoryl group
● Macromolecule with a polar head and a nonpolar tail
● Cell membrane
■ Glycolipids
● Bound to carbohydrates
● Important membrane constituents
■ Steroids
● Polycyclic hydrocarbons
● Function as hormones that control a variety of physiological
functions
● eg. cholesterol → vital membrane component
11.1 - Fatty Acids Are a Main Source of Fuel
● Fats/fatty acids: chains of hydrogen-bearing carbon atoms (hydrocarbons) that
terminate with carboxylic acid groups
○ Fuel, building blocks for membrane lipids
○ Names
■ Systematic name → derived from the name of its parent hydrocarbon
by the substitution of oic for the final e
● eg. C18 saturated fatty acid (stearic acid) → octadecanoic acid
○ Parent hydrocarbon is octadecane
■ Numbers
● eg. C18 saturated fatty acid → 18:0 (18 C atoms, 0 double
bonds)
● eg. C18 unsaturated
fatty acid → 18:2 (18 C atoms, 2 double
bonds)
○ Saturated: fatty acid composed of only single bonds
○ Unsaturated: fatty acid with 1+ double/triple bonds
○ Fatty acid carbon atoms are usually numbered starting at the terminal carbon
atom
Chapter 11 - Lipids
● Lipids: water-insoluble molecules that are highly soluble in organic solvents
○ Store energy, key components of membranes, signal-transduction pathways
○ 5 classes
■ Free fatty acids (nonesterified fatty acids)
● Fuel and components of membrane lipids
● Vary in hydrocarbon chain length
■ Triacylglycerols
● The storage form of fatty acids
■ Phospholipids
● Consist of fatty acids attached to a scaffold that also bears a
charged phosphoryl group
● Macromolecule with a polar head and a nonpolar tail
● Cell membrane
■ Glycolipids
● Bound to carbohydrates
● Important membrane constituents
■ Steroids
● Polycyclic hydrocarbons
● Function as hormones that control a variety of physiological
functions
● eg. cholesterol → vital membrane component
11.1 - Fatty Acids Are a Main Source of Fuel
● Fats/fatty acids: chains of hydrogen-bearing carbon atoms (hydrocarbons) that
terminate with carboxylic acid groups
○ Fuel, building blocks for membrane lipids
○ Names
■ Systematic name → derived from the name of its parent hydrocarbon
by the substitution of oic for the final e
● eg. C18 saturated fatty acid (stearic acid) → octadecanoic acid
○ Parent hydrocarbon is octadecane
■ Numbers
● eg. C18 saturated fatty acid → 18:0 (18 C atoms, 0 double
bonds)
● eg. C18 unsaturated
fatty acid → 18:2 (18 C atoms, 2 double
bonds)
○ Saturated: fatty acid composed of only single bonds
○ Unsaturated: fatty acid with 1+ double/triple bonds
○ Fatty acid carbon atoms are usually numbered starting at the terminal carbon
atom
