The Chemical Composition of Nutrient Agar

The Chemical Composition of Nutrient Agar
••• Stockbyte/Stockbyte/Getty Images

Bacteria are single-celled organisms that can be found in multiple environments. In order to study the characteristics of bacteria, biologists grow them in the laboratory under controlled conditions. In order to do this, the bacteria have to be placed into a medium that provides them with the optimum growth conditions. Nutrient agar is one of the most common growth mediums and consists of a variety of different chemicals.

Agar

A large proportion of nutrient agar consists of the chemical agar. Agar is a gelatinous mixture that is extracted from seaweed. When mixed with water, a 1.5 percent agar solution forms a gel when cooled to below 45 degrees Celsius (113 degrees Fahrenheit). Agar consists of a mixture of sugar polymers (polysaccharides), where the basic sugar is galactose.

Peptone

Peptone is a mixture of proteins and amino acids that is obtained by breaking down natural products such as animal tissues, milk and plants. The function of peptone in nutrient agar is to provide a protein source so that micro-organisms can grow.

Sodium Chloride

Sodium chloride is the most well-known salt and consists of a single sodium ion that is bonded to a single chlorine ion. The presence of sodium chloride in nutrient agar maintains a salt concentration in the medium that is similar to the cytoplasm of the microorganisms. If the salt concentration is not similar, osmosis takes place transporting excess water into or out from the cell. Both of these scenarios can be lead to the death of the cell.

Water

Water makes up a large proportion of nutrient agar, with 1 liter being added for every 15 grams (0.5 Ounce) of agar. Water is essential for the growth of and reproduction of micro-organisms and also provides the medium through which various nutrients can be transported.

Related Articles

How Enterococcus Faecalis Changes the Mannitol Salt...
Types of Agar Plates
Characteristics of Salmonella Bacteria
What Products Are Made From Seaweed?
The Effects of Salt Concentration on Bacterial Growth
How To Make Citric Acid
What Are Agar Slants?
Types of Spore Forming Bacteria
Why Are Agar Plates Kept Inverted Whenever Possible?
What Types of Bacteria Produce Endospores?
How to Make Agar Gel From Powder
What Types of Bacteria Produce Nitrate?
Similarities Between Fungi & Algae
How to Grow Bacteria in Agar
How to Make Your Own Agar for Petri Dishes
How to Stain Chitin
How to Make Skim Milk Agar Plates
How Does Alcohol Kill Bacteria?

Dont Go!

We Have More Great Sciencing Articles!