22 Biology -- Monera

Differentiate between gram positive bacteria and gram negative bacteria.

1 Answers

On the basis of the cell wall structure and stain ability with the Gram's stain, bacteria are classified into two groups: Gram positive and Gram negative.

Gram positive bacteria	Gram negative bacteria
The bacteria which retain blue color of crystal violet dye after decolorizing by alcohol are called Gram positive bacteria.	The bacteria which lose blue color of crystal violet dye after decolorizing of alcohol are known as Gram negative bacteria.
1. Cell wall is 25-30 nm thick and has 1 layer.	1. Cell wall is 10-15 nm thick and has 3
2. Peptidoglycan (murein) occupies 20-80% of dry weight of cell wall.	2. Peptidoglycan (murein) constitutes 10-20% of dry weight of cell wall.
3. Retains the Gram's stain, i.e. show purple or dark violet color.	3. Lose gram's stain. They can be stained with safranin.
4. Very little lipid contents ( 0-2%).	4. High lipid content (10-20%).
5. Lipopolysaccharide layer is absent.	5. Lipopolysaccharide layer is present.
6. susceptible to antibiotics( lysosomes).	6. Due to presence of high lipid content, it is resistant to lysosomes.
7.Spore-forming bacilli, many cocci. Example: Staphylococcus, Streptococcus, Mycobacterium, etc.	7. Most non spore-forming bacilli, spirals and some cocci. Example: Rhizobium, Vibrio, Salmonella, etc.

'Bacteria are friends and foes equally' comment upon this statement.

Bacteria acts as both advantageous as well as disadvantageous aspects in various activities related to our daily life. Some of its roles are mentioned below:

Beneficial effects of Bacteria:

Role in agriculture

Nature’s scavengers (ammonifying bacteria): Saprophytic bacteria cause decay and decomposition of dead plants or animals and release the raw-materials for mew generation.Eg, Bacillus mycoides, B. ramosus, and B. vulgaris, etc.
Nitrifying Bacteria: Nitrifying bacteria (Nitrosomonas and...

Describe the systematic position, cell structure of bacteria.

Systematic Position

Kingdom : Monera

Division : Eubacteria

Order : Eubacteriales

Type : Bacteria

Cell Structure of Bacteria

Bacteria are small unicellular, microscopic organisms. Under electron microscope, bacteria show a small tiny mass of protoplasm surrounded by a cell wall.

Cell wall :The cell are extremely covered by rigid cell wall. Main component of cell wall is peptidoglycan or mucopeptide or murein. The peptidoglycan is composed of amino sugars and amino acids. Consists of lipids...

Write a note on bacterial growth.

Bacterial growth

Bacterial growth is a phenomenon of multiplication of bacterial cell into 2,4,8 and many daughter cells that occurs mostly by binary fusion. Cell division involved is mostly amitosis so daughter cells are genetically identical to the parent cell. Multiplication finally results into a bacterial population which shows an exponential growth. Thus bacterial growth occurs

Batch culture is the most common technique used to grow or culture microorganisms including bacteria. Here a...

Write economic importance of bacteria.

The economic importance of bacteria are mentioned below:

Beneficial effects of Bacteria:

Role in agriculture

Nature’s scavengers (ammonifying bacteria): Saprophytic bacteria cause decay and decomposition of dead plants or animals and release the raw-materials for mew generation.Eg, Bacillus mycoides, B. ramosus, and B. vulgaris, etc.
Nitrifying Bacteria: Nitrifying bacteria (Nitrosomonas and Nitrobacter) convert ammonium compounds into nitrates. It occurs in two steps: In the first step ammonia...

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