Lecture notes in Microbiology

Difference between Pili and Flagella of Bacteria- A Comparison Table


Fimbria vs pilus

Flagella vs Pili of Bacteria: A Comparison Table
(Similarities and Differences between Pili and Flagella of Bacteria)

Both Flagellum (plural Flagella) and Pilus (plural Pili) are the filamentous proteinaceous structures found on the surface of some bacterial cells. They extend from the surface of the bacterial cell wall and can have many functions such as motility, attachment, adhesion and assisting in genetic exchange.

Flagella definition: Bacterial flagella are long whip-like filamentous structures present in some bacteria. The most important function of flagella is to assist in locomotion. Flagella can also act as a sensory organ to detect temperature and the presence of certain chemicals in the external environment of the cell. Even though the flagella are present in prokaryotes and eukaryotes, both are entirely different in their structure, formation and mechanism of propulsion.

Pili definition: Pili are long hair like tubular micro-fibres like structures present on the surface of some Gram-negative bacteria. They are comparatively shorter filamentous structures than flagella and their number per cell is very limited. There are many classes of pili based on their structure and function. Most of the pili can act as the receptors of some viruses.

The present post describes the Similarities and Differences between Flagella and Pili with a Comparison Table

Similarities between Flagella and Pili

Ø  Both flagella and pili are filamentous structures.

Ø  Both are cell surface appendages.

Ø  Both are made up of proteins.

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Lecture notes in Microbiology

Difference between Flagella and Fimbriae of Bacteria- A Comparison Table


Difference between Fimbriae and Flagella

Fimbriae vs Flagella
(Similarities and Differences between Fimbriae and Flagella of Bacteria)

Both Fimbria (plural Fimbriae) and Flagellum (plural flagella) are the filamentous proteinaceous structures found on the surface of some bacterial cells. 

Fimbriae definition: Fimbriae are bristle like short fibres occurs on the surface of some Gram positive and Gram negative bacteria. Fimbriae enable the bacterial cell to stick to the surface of host cells. They also help in the formation of pellicles or biofilms. (Pellicle: thin sheet of cells on the surface of a liquid).

Flagella definition: Bacterial flagella are long whip like filamentous structures present in some bacteria. The most important function of flagella is to assist in locomotion. Flagella can also act as a sensory organ to detect temperature and the presence of certain chemicals in the external environment of the cell. Even though the flagella are present in prokaryotes and eukaryotes, both are entirely different in their structure and formation and mechanism of propulsion.

The present post describes the Similarities and Differences between Fimbriae and Flagella of bacteria with a Comparison Table.

Similarities between Fimbriae and Flagella

Ø  Both fimbriae and flagella are filamentous structures.

Ø  Both are present in Gram positive and Gram negative bacteria.

Ø  Both are cell surface appendages, present on the cell surface of bacteria.

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Lecture notes in Microbiology

Difference between Pili and Fimbriae of Bacteria- A Comparison Table


Difference between Pili and Fimbriae

Fimbriae vs Pili
(Similarities and Differences between Fimbriae and Pili of Bacteria)

Both Fimbria (plural Fimbriae) and Pilus (plural Pili) are the filamentous proteinaceous structures found on the surface of some bacterial cells. They extend from the surface of the bacterial cell wall and can have many functions such as attachment, adhesion and assisting in genetic exchange.

Fimbriae definition: Fimbriae are bristle like short fibres occurs on the surface of some Gram positive and Gram negative bacteria. Fimbriae enable the bacterial cell to stick to the surface of host cells. They also help in the formation of pellicles or biofilms. (Pellicle: thin sheet of cells on the surface of a liquid).

Pili definition:  Pili are long hair like tubular micro-fibres like structures present on the surface of some Gram negative bacteria. They are comparatively longer filamentous structures and their number per cell is very limited. There are many classes of pili based on their structure and function. Most of the pili can act as the receptors of some viruses.

The term Pili and Fimbriae are used inter-changeably by many authors in many microbiology text books. However, modern studies have clearly shown that they are two different entities in the bacteria distinguished by their development, structure and functions.

The present post describes the Similarities and Differences between Fimbriae and Pili with a Comparison Table

Similarities between Fimbriae and Pili

Ø  Both fimbriae and pili are filamentous structures.

Ø  Both are cell surface appendages, present on the cell surface of bacteria.

Ø  Both are the attachment or adhesion organs in bacteria.

Ø  Both are made up of proteins.

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Lecture notes in Microbiology

Difference between Murein and Pseudomurein- A Comparison Table


difference murein and pseudomurein

Murein vs Pseudomurein – A Comparison Table
(Similarities and Difference between Peptidoglycan and Pseudopeptidoglycan)

The majority of Bacteria and Archaebacteria have a rigid cell wall around its plasma membrane. The peptidoglycan (also called murein) cell wall, which is considered as the biomarker of bacteria, is absent in the cell wall of Archaea. However, the members of Archaea show great diversity in their cell wall composition. The cell wall in Archaea may contain polysaccharides, proteins or glycoproteins. Some methanogenic Archaebacteria possess a cell wall molecule that is remarkably similar to that of the peptidoglycan molecules in the cell wall of bacteria. These cell wall molecules are called Pseudopeptidoglycan or Pseudomurein. The peptidoglycan and pseudopeptidoglycan shows many structural and functional similarities and differences. The present post describes the Similarities and Differences between the Peptidoglycan (Murein) and Pseudopeptidoglycan (Pseudomurein) with a comparison table.

Similarities between Peptidoglycan (Murein) and Pseudopeptidoglycan (Pseudomurein)

Ø. Both Peptidoglycan and Pseudopeptidoglycan are glycoconjugates.

Ø. Both are polymers of monomer units joined by specific glycosidic bonds.

Ø. Both are hetero-polysaccharides (consists of more than one type of monomer units).

Ø. Both contain long un-branched carbohydrate chains inter-connected by short peptide segments.

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Botany lecture notes

Difference between Sieve Tubes and Sieve Cells- A Comparison Table


sieve cells and sieve tubes differences

Sieve Tubes vs Sieve Cells
(Similarities and Differences between Sieve Tubes and Sieve Cells)

Phloem is a permanent vascular tissue system associated with the conduction of food materials in plants. It is a complex tissue composed of more than one type of cells namely sieve elements, companion cells, phloem fibres and phloem parenchyma. Among these cells, the sieve elements are the most specialized cells in the phloem performing the conduction of food materials. There are two types of sieve elements are described among vascular plants based on structural complexity and evolutionary significance. They are (1) Sieve Cells and (2) Sieve Tubes. The present post describes the similarities and differences between sieve cells and sieve tubes as a comparison table.

Similarities between Sieve Cells and Sieve Tubes

Ø  Both sieve cells and sieve tubes components of phloem.

Ø  Both are the sieve elements (a category of phloem cells).

Ø  Both sieve cells and sieve tubes transport food materials.

Ø  Both are living cells.

Ø  Both cells have thin primary cell wall (secondary thickening absent).

Ø  Both contain dense granular protoplasm.

Ø  Nucleus is absent in both sieve cells and sieve tubes.

Ø  Both present in primary and secondary phloem.

Difference between Sieve Cells and Sieve Tubes

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