Bacterial Flagella Structure and Function

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Questions and Answers

How is the flagellum of E. coli typically sized?

10 µm long with a diameter of 20 nm

How many substructures is the bacterial flagellum divided into?

Where are polar flagella located on a bacterial cell?

One spot on the cell

In what process does flagellum assembly start with?

CM-associated components of the basal body and the secretion apparatus Signup and view all the answers

Which protein is the major subunit of the flagellum?

Flagellin (FliC) Signup and view all the answers

Apart from motility, what other function do flagella serve?

Biofilm formation and adhesion Signup and view all the answers

Match the following cellular structures with their functions:

Cell wall = Provides shape and protects from external pressures Ribosomes = Involved in protein synthesis Nucleoid region = Area where genetic material is located Flagella = Involved in cell movement Signup and view all the answers

Match the following cellular structures with their characteristics:

Prokaryotic cell wall = Thicker in bacteria than archaea Nucleoid region = Surrounded by a nuclear membrane Ribosomes = Translate messenger RNA into proteins Plasmids = Involved in cell movement Signup and view all the answers

Match the following cellular structures with their composition:

Cell wall = Varies between prokaryotes Ribosomes = Composed of ribosomal RNA and proteins Nucleoid region = Composed of DNA, RNA, and enzymes Plasmids = Composed of proteins and ions Signup and view all the answers

Match the following cellular structures with their types of cells:

Nucleoid region = Present in prokaryotic cells Ribosomes = Present in eukaryotic cells Flagella = Present in eukaryotic cells Plasmids = Present in prokaryotic cells Signup and view all the answers

Match the following cellular structures with their functions in protein synthesis:

Ribosomes = Translate messenger RNA into proteins Nucleoid region = Transcribe DNA into RNA Cell wall = Provide shape and protect from external pressures Plasmids = Regulate protein synthesis Signup and view all the answers

Match the following cellular structures with their characteristics in prokaryotic cells:

Nucleoid region = Lacks a membrane-bound structure Cell wall = Thicker in bacteria than archaea Ribosomes = Composed of ribosomal RNA and proteins Plasmids = Small, circular DNA molecules Signup and view all the answers

Match the following structures with their functions in prokaryotic cells:

Flagella = Enabling cells to move through their environment Plasmids = Providing resistance to antibiotics Cell wall = Surrounding the cell and maintaining its shape Ribosomes = Synthesizing proteins Signup and view all the answers

Match the following components with their characteristics in prokaryotic cells:

Flagellin = Protein found in flagella Peptidoglycan = Polymer of sugars and amino acids in the cell wall Nucleoid region = Region where DNA is found Plasmids = Chromosomal DNA structures Signup and view all the answers

Match the following terms with their descriptions in prokaryotic cells:

Flagella = Whip-like structures Plasmids = Non-chromosomal DNA structures Cell wall = Structure composed of peptidoglycan Ribosomes = Sites of protein synthesis Signup and view all the answers

Match the following structures with their functions in prokaryotic cells:

Flagella = Enabling cells to move Plasmids = Carrying genes for antibiotic resistance Cell wall = Maintaining cell shape Nucleoid region = Storing genetic information Signup and view all the answers

Match the following components with their functions in prokaryotic cells:

Flagellin = Enabling flagella movement Peptidoglycan = Providing structural support Plasmids = Transferring beneficial genes Ribosomes = Synthesizing proteins Signup and view all the answers

Match the following structures with their characteristics in prokaryotic cells:

Flagella = Helical pattern Plasmids = Non-reproductive DNA Cell wall = Polymer of sugars and amino acids Nucleoid region = Region without a true nucleus Signup and view all the answers

Study Notes

Flagella are hairlike structures that act as an organelle of locomotion in prokaryotic and eukaryotic cells. Bacteria have flagella for movement and chemotaxis. The flagellum is composed of about 60 structural and regulatory proteins, including flagellin or FliC, which is the major subunit of the flagellum. The flagellum of Escherichia coli is typically about 10 µm long with a diameter of 20 nm.

Bacterial flagella come in two main types: polar and peritrichous. Polar flagella are located at one spot on the cell, while peritrichous flagella cover the entire cell surface. The flagellum is a supramolecular structure divided into three substructures: the filament, the hook, and the basal body. The filament is composed of about 20,000 flagellin (FliC) proteins, which are incorporated below the distal pentameric FliD cap.

The bacterial flagellum is assembled through a complex process involving several proteins. Flagellum assembly starts with the CM-associated components of the basal body and the secretion apparatus, followed by the remaining basal body components, the hook and hook-filament junction proteins, and finally the filament capping proteins.

Flagella not only serve as motility organelles but also have other functions. They can participate in biofilm formation, protein export, and adhesion. Flagellin, the major subunit of the flagellum, has been shown to function as an adhesin, playing a role in bacterial adhesion to and invasion into host cells. In various pathogens, such as Escherichia coli, Pseudomonas aeruginosa, and Clostridium difficile, flagellin and the distally located flagellar cap protein have been reported to function as adhesins.

In summary, bacterial flagella are complex structures composed of multiple proteins that serve as motility organelles and have additional functions such as adhesion and biofilm formation. The assembly process involves several proteins and the flagellum can have different types and numbers depending on the bacterial species.