8 public questions tagged with this topic.
Pili are small, bristle-like structures on the bacterial surface that help in attachment to host tissues. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Generation time defines kinetic metric of prokaryotic proliferation, interval required for population to double in cell number during balanced growth. Since bacteria propagate by binary transverse fission, each mother cell splits into two genetically identical daughters after chromosome replication, partition via ParABS, and septal wall formation by divisome. Therefore cell number doubling corresponds to one complete cell cycle. During exponential phase generation time g remains constant, specific growth rate mu equals 0.693 over g. Values vary dramatically: Vibrio natriegens fastest known 10
Ref: Prescott's Microbiology, 11th ed., Chapter 7: Generation time and doubling.
The glycocalyx varies in composition and thickness. In some bacteria it occurs as a loose sheath called the slime layer, while in others it forms a thick and tough capsule.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model
Helicobacter pylori represents microaerophilic curved Gram-negative bacterium classified within class Epsilonproteobacteria of phylum Proteobacteria based on 16S rRNA phylogeny, unipolar flagellation, and microaerophilic physiology. It colonizes human gastric mucosa using urease producing ammonia to neutralize gastric acid, adhesins and cytotoxins CagA and VacA triggering inflammation. Strong association with chronic gastritis, peptic ulcers, and gastric adenocarcinoma established it as type species of Helicobacter. Its proteobacterial affiliation contrasts with Spirochaetes, Firmicutes, and A
Ref: Tortora Microbiology 12th ed., Chapter 11 Epsilonproteobacteria Helicobacter; Bergey's Manual Volume 2 Proteobacteria Helicobacter pylori gastric
Borrelia burgdorferi sensu lato complex comprises Ixodes tick-borne spirochetes causing Lyme borreliosis, the most common vector-borne illness in temperate regions worldwide. These diderm spirochetes possess linear chromosome and numerous linear and circular plasmids encoding antigenically variable outer surface proteins OspA-OspC facilitating immune evasion through antigenic switching. Characteristic flat-wave morphology and periplasmic flagella enable dissemination through connective tissue leading to erythema migrans, arthritis, carditis, and neuroborreliosis. Taxonomy within Spirochaetacea
Ref: CDC Lyme Disease Borrelia burgdorferi tick-borne; Jawetz Medical Microbiology 27th ed., Borrelia spirochete linear chromosome plasmids
Treponema pallidum subspecies pallidum is a fastidious microaerophilic spirochete exhibiting distinctive corkscrew morphology with endoflagella located within periplasmic space between outer membrane and cytoplasmic cylinder, driving motility in viscous environments like mucosal secretions. Unable to be continuously cultured in vitro, it transmits via sexual contact causing syphilis characterized by primary chancre, secondary disseminated rash, and tertiary gummas, cardiovascular and neural damage. Taxonomic placement in family Spirochaetaceae reflects helical coiling, outer sheath lacking lip
Ref: CDC Syphilis Treponema pallidum spirochete; Jawetz Medical Microbiology 27th ed., Spirochaetes Treponema morphology dark-field
