Q.4 Bacterial species showing several flagella at one pole are called:

1. Monotrichous
2. Lophotrichous
3. Amphitrichous
4. Peritrichous

   Lophotrichous bacteria have several flagella clustered at one pole, enabling rapid directional motility through bundled rotation.

   Question Breakdown

   Bacterial flagella arrangements classify motility patterns based on number and position, crucial for taxis (chemotaxis/phototaxis) in microbiology. The query specifies “several flagella at one pole,” distinguishing polar tuft arrangements from others.​​

   Option Analysis

   Monotrichous

   Monotrichous bacteria bear a single flagellum at one pole (e.g., Vibrio cholerae). It propels via simple rotation, not a tuft of multiple flagella.​​

   Lophotrichous

   Lophotrichous describes multiple flagella (tuft or bundle) at one pole (sometimes both), as in Spirillum volutans or Pseudomonas. Bundling allows high-speed swimming by synchronized waves.​

   Amphitrichous

   Amphitrichous bacteria have one flagellum (or rarely more) at each pole (e.g., Alcaligenes faecalis), enabling push-pull movement, not several at one end.​​

   Peritrichous

   Peritrichous feature flagella distributed over the entire cell surface (e.g., Escherichia coli, Salmonella). They run/tumble via random bundling.​​

   Correct Answer: Lophotrichous – Matches “several flagella at one pole” precisely.​

   Bacterial species showing several flagella at one pole are classified as lophotrichous, featuring a polar tuft for enhanced motility in aquatic environments. This arrangement optimizes chemotaxis, vital for microbial ecology and pathogenesis studies.

   Flagella Arrangement Types

   Bacterial motility hinges on flagellar distribution:

   • Monotrichous: Single polar flagellum.​

   • Lophotrichous: Tuft at one pole (e.g., Helicobacter).​

   • Amphitrichous: Flagella at both poles.​

   • Peritrichous: All over body.​

   Lophotrichous bundles rotate clockwise/counterclockwise for smooth runs.​

   Biological Significance

   Polar tufts enable faster speeds than monotrichous (up to 100 μm/s), aiding evasion or nutrient seeking. Relevant to your microbiology focus, observed via electron microscopy post-staining.​

   Type	Flagella Position	Examples
   Monotrichous	One at one pole	Vibrio cholerae​
   Lophotrichous	Several at one pole	Spirillum​
   Amphitrichous	One at each pole	Alcaligenes​
   Peritrichous	All over surface	E. coli​