Lipids and Fats Overview

Study Notes

Lipids are macro-molecules that contain hydrocarbons.
Lipids are the structural and functional building units of living cells.
Lipids are mainly composed of hydrocarbons.
Lipids are highly reduced forms of carbon.
Lipids are non-polar molecules.
Lipids are not soluble in water.
Lipids are soluble in non-polar solvents, e.g., chloroform, acetone, or ether.
In plants, lipids are stored as energy reserves in seeds and fruits.
Lipids are a source of energy for germination and growth.
Lipids form a part of membranes around cells.
Lipids make up the bilayer of plant cell membranes.
Lipids are essential for maintaining cell integrity and regulating nutrient and water uptake.
Lipids are precursors of hormones and vitamins.

Fatty acids are amphipathic molecules.
Fatty acids contain both hydrophilic regions and hydrophobic regions.
The hydrophilic region of a fatty acid is the carboxyl group (polar head group).
The hydrophobic region of a fatty acid is the long hydrophobic chain.

Saturated fatty acids: have no double bonds between carbon atoms in their hydrocarbon chains.
Unsaturated fatty acids: have one or more double bonds between carbon atoms.
Monounsaturated fatty acids: have one double bond.
Polyunsaturated fatty acids: have two or more double bonds.

Cis-bonds: Both hydrogen atoms attached to the double bond are on the same side of the carbon chain.
Trans-bonds: The hydrogen atoms attached to the double bond are on opposite sides of the carbon chain.

Unsaturated fatty acids are more susceptible to oxidation and can become rancid.
Unsaturated fatty acids are more easily broken down by enzymes.

Plant and animal fatty acids differ in their composition.
For example, plant oils are typically rich in unsaturated fatty acids, while animal fats are typically rich in saturated fatty acids.

Lipids can be named based on their structure and composition.
For example, triacylglycerol is named based on the three fatty acids that are attached to glycerol.