EVERYDAY SCIENCE

Detailed explanation-1: -Two types of surface appendage can be recognized on certain bacterial species: the flagella, which are organs of locomotion, and pili (Latin hairs), which are also known as fimbriae (Latin fringes). Flagella occur on both Gram-positive and Gram-negative bacteria, and their presence can be useful in identification.

Detailed explanation-2: -Pili and flagella perform crucial actions on the bacterial cell surface such as motility, adhesion and the uptake and excretion of proteins and DNA. These structures can grow to many times the size of the cell, withstand and generate high forces and form and disassemble rapidly in response to environmental cues.

Detailed explanation-3: -Pili are characteristic of Gram-negative bacteria. In fact, virtually all Gram-negative bacteria produce pili of one type or another but can also be found in Gram positive microorganisms.

Detailed explanation-4: -Many Gram-positive and Gram-negative bacterial species and also Archaea as well as some eukaryotic cells have a flagellum (’whip’ in Latin). Flagellum is primarily a motility organelle that enables movement and chemotaxis.

Detailed explanation-5: -Prokaryotes often have appendages (protrusions) on their surface. Flagella and some pili are used for locomotion, fimbriae help the cell stick to a surface, and sex pili are used for DNA exchange. Most prokaryotic cells have a single circular chromosome.