Lipids

4.4

Lipids

Introduction

Lipids are naturally occurring hydrophobic compounds found in plant and animal tissues.
Like carbohydrates, lipid is made up of carbon, hydrogen and oxygen elements but with a much higher ratio of hydrogen atoms to oxygen atoms.
Lipids are insoluble in water but soluble in other organic solvents, for example, alcohol, ether and chloroform.

Types of Lipids

Wax

Wax contains one molecule of alcohol that combines with another molecule of fatty acid and is waterproof.

Phospholipid

Phospholipids are a major component of plasma membranes and are made up of one molecule of glycerol that combines with two molecules of fatty acid and one group of phosphate.

Steroid

Fats

Fats and oils are triglycerides.
Triglycerides are a type of ester formed from the condensation of one glycerol molecule with three molecules of fatty acids.
Triglycerides can be hydrolysed again into fatty acids and glycerol through the reaction of hydrolysis.
Glycerols are a type of three carbon alcohol that contain three hydroxyl groups (–OH).
There are two types of fatty acids, namely saturated fatty acids and unsaturated fatty acids.
Similarities of saturated fatty acids and unsaturated fatty acids.
- Both consist of carbon, hydrogen and oxygen elements.
- Both contain glycerol and fatty acids.
- Both contain nonpolar molecules.

Saturated Fatty Acids	Unsaturated Fatty Acids
Fatty acids only have single bonds between carbon.	Fatty acids have at least one double bond between carbon.
Do not form chemical bonds with additional hydrogen atoms because all bonds between carbon atoms are saturated.	Double bonds can still receive one or more additional hydrogen atoms because carbon atoms are unsaturated.
Exist in solid form at room temperature.	Exist in liquid form at room temperature.
Source: butter and animal fat.	Source: olive and fish oil.

Importance of Lipids in Cells

Fats function as reserved energy for animals.
In addition, fats also function as a liner to protect internal organs and act as a heat insulator for animals.
Waxes are an important component in cuticles that cover the epidermis of leaves and sebum secreted by our skin.
The function of glycolipid is to ensure the stability of the plasma membrane and to help in the cell identification process.
Cholesterol is important in steroid hormone synthesis.

4.4

Lipids

Introduction

Lipids are naturally occurring hydrophobic compounds found in plant and animal tissues.
Like carbohydrates, lipid is made up of carbon, hydrogen and oxygen elements but with a much higher ratio of hydrogen atoms to oxygen atoms.
Lipids are insoluble in water but soluble in other organic solvents, for example, alcohol, ether and chloroform.

Types of Lipids

Wax

Wax contains one molecule of alcohol that combines with another molecule of fatty acid and is waterproof.

Phospholipid

Phospholipids are a major component of plasma membranes and are made up of one molecule of glycerol that combines with two molecules of fatty acid and one group of phosphate.

Steroid

Fats

Fats and oils are triglycerides.
Triglycerides are a type of ester formed from the condensation of one glycerol molecule with three molecules of fatty acids.
Triglycerides can be hydrolysed again into fatty acids and glycerol through the reaction of hydrolysis.
Glycerols are a type of three carbon alcohol that contain three hydroxyl groups (–OH).
There are two types of fatty acids, namely saturated fatty acids and unsaturated fatty acids.
Similarities of saturated fatty acids and unsaturated fatty acids.
- Both consist of carbon, hydrogen and oxygen elements.
- Both contain glycerol and fatty acids.
- Both contain nonpolar molecules.

Saturated Fatty Acids	Unsaturated Fatty Acids
Fatty acids only have single bonds between carbon.	Fatty acids have at least one double bond between carbon.
Do not form chemical bonds with additional hydrogen atoms because all bonds between carbon atoms are saturated.	Double bonds can still receive one or more additional hydrogen atoms because carbon atoms are unsaturated.
Exist in solid form at room temperature.	Exist in liquid form at room temperature.
Source: butter and animal fat.	Source: olive and fish oil.

Importance of Lipids in Cells

Fats function as reserved energy for animals.
In addition, fats also function as a liner to protect internal organs and act as a heat insulator for animals.
Waxes are an important component in cuticles that cover the epidermis of leaves and sebum secreted by our skin.
The function of glycolipid is to ensure the stability of the plasma membrane and to help in the cell identification process.
Cholesterol is important in steroid hormone synthesis.