Chapter 5: Organic Molecules of Life (Lipids)

What is special about lipids?

The one type of macromolecule that is not polymeric

What are the 3 major types of lipids?

Fats, Phospholipids, Steroids

How are fats made of?

3 fatty acids + 1 glycerol molecule joined by an ester linkage (trigycleride)

Glycerol

3-carbon alcohol with a hydroxyl attached to each carbon

Fatty Acids

Carboxyl group head attached to a long hydrocarbon chain skeleton

What are the 2 ways to differentiate fatty acids?

1. Length (# of carbons in skeleton)

2. Number/Location of double bonds

Saturated vs. Unsaturated Fatty Acids

Saturated → no double bonds (max number of hydrogen atoms attached)

Unsaturated → 1 or more double bonds

What do fats look like in everyday life?

Saturated Fats → solid at room temperature (animal fat)

Unsaturated Fats → liquid at room temperature (plant/fish fats)

Why are saturated fats solid at room temperature? Why not unsaturated fats as well?

Their straight molecular chains pack tightly together

The bends in unsaturated bonds prevent close packing

What is the function of fats?

Long-term energy storage, usually stored in adipose tissue

Hydrogenation

Converts unsaturated fats to saturated fats by adding hydrogen, removing double bonds

How are phospholipids made?

2 fatty acid molecules + phosphate group + 1 glycerol molecule

What is the charge of the phospholipids tail? The head?

Tail → hydrophobic (nonpolar)

Head → hydrophilic (polar)

What are steroids made of?

Carbon skeleton made up of four ring structures fused together

What is the function of steroids?

Cell membrane stability (cholesterol in animals)