Question

Motile bacteria possess (a) Cilia (b) Flagella (c) Both (a) and (b) (d) None of these

Short answer

The correct answer is (b) Flagella. Bacteria use flagella for movement.

Step-by-step solution

Understanding of Motile Bacterial Structures

Firstly, when talking about bacteria, we need to understand that these are microorganisms that lack a nucleus and other important organelles due to being prokaryotes, yet they are capable of more complexity than this would suggest. One of these complexities is their capacity for movement.

Identify the locomotive structure of bacteria

Motile bacteria use whip-like structures called flagella for movement. They rotate these flagella to push themselves forward. Some bacteria have a single flagellum, others have many flagella. Cilia, on the other hand, are typically found in eukaryotic organisms where they can be present along the entire surface of the cell, moving in coordinated waves.

Determining the Correct Option

Since bacteria use flagella for movement, and not cilia, we can rule out options (a) and (c). Option (d) can also be ruled out since bacteria do utilize flagella for locomotion. As such, option (b) must be the correct choice.

Key concepts

Flagella

Motile bacteria rely on flagella for their movement. These flagella are long, thin, whip-like appendages that extend from the cell body. They play a crucial role in enabling movement or locomotion.

Flagella move in a whip-like manner, which propels bacteria forward. This is achieved through a rotational movement. By spinning their flagella like tiny propellers, bacteria can move in liquid environments. Some bacteria possess a single flagellum, while others have numerous flagella, which can be strategically located around their cell bodies.

This movement capability allows bacteria to navigate towards favorable environments, such as those rich in nutrients, or away from harmful conditions.

Prokaryotes

Bacteria are classified as prokaryotes. Prokaryotes are organisms that lack a defined nucleus and other membrane-bound organelles. Unlike eukaryotes, prokaryotic cells contain a single, circular chromosome located in a region called the nucleoid, along with plasmids, which are small circular DNA molecules.

The simplicity of prokaryotic cellular structure allows for rapid growth and replication. This makes bacteria highly adaptable and capable of thriving in diverse environments. Despite their simplicity, some prokaryotes like motile bacteria have developed complex movement systems, such as flagella, to enhance their survival and adaptability.

Locomotion in Microorganisms

Locomotion is a fascinating aspect of microorganism behavior, enabling them to move in various environments. In bacteria, locomotion is primarily facilitated by flagella. This allows them to move towards nutrients or away from harmful stimuli, ensuring their survival.

Microbial locomotion is essential for processes like chemotaxis, which is the movement towards or away from chemical stimuli. Bacteria use their flagella to navigate through environments by following increasing concentrations of nutrients (positive chemotaxis) or moving away from toxic substances (negative chemotaxis).

Overall, locomotion in microorganisms is a vital adaptive feature, allowing them to effectively respond to changes in their surroundings and maintain their colonies in optimal conditions.