Chapter 3, Problem 10RQ

Summary Introduction

To review:

The contrasting and comparing bacterial structures of motility and attachment along with the molecular basis of chemotaxis.

Introduction:

Prokaryotic cells are covered by cell walls having several surface appendages or protrusions. These surface appendages are pili, fimbriae, and flagella that are involved in cellular movement and locomotion. Prokaryotic cells consist of circular DNA (Deoxyribonucleic acid) and chromosome. The locomotion of cells helps in finding the food and to change their location in case of environmental stress.

Bacteria are prokaryotes lacking a true or membrane-bound nucleus and organelles. Bacterial cellular structures include ribosomes, capsule, cytoplasm, cell wall, pili, and flagella. The pili and flagella are the two main bacterial features or structures that are associated with bacterial locomotion. The differences between flagella and pili are listed below:

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The movement of motile structures or cells in the direction of increasing or decreasing gradient or chemical is known as chemotaxis. Chemoreceptors behave like a nose and guide the bacteria to swim toward the attractant source. Chemotaxis with the help of rotary flagella propels the cell away or toward the repellants and attractants, respectively.