Lecture7

Lecture7 - Lecture 7 Structural Features of Prokaryotic...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Lecture 7 Structural Features of Prokaryotic Cells continued B. Anatomy of Prokaryotic Cells 9 Bacterial shapes and configuration 9 Cell membrane 9 Cell Wall Gram - positive Gram – negative Outline Structural Features of Prokaryotic Cells. C. Structures External to the Cell Wall. Glycocalyx (EPS) Flagella Fimbriae and Pili D. Inside Cell Membrane Cytoplasm ( Ribosomes,inclusions, gas vesicles) Nucleoid Spores Gram negative Gram positive Fig. 4.14 Glycocalyx Sugar coat - polysaccharide, external to outer cell surface Synthesized inside the cell and transported to the cell's surface. If it remains attached to surface - called capsule or extracellular polysaccharide (EPS) If only loosely attached - called slime layer . Bacterial Glycocalyx Fig. 4.12
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Glycocalyx Functions: It prevents dehydration - polysaccharides adsorb water It protects the cell. ( virulence factor ) In pathogenic bacteria we find that it inhibits phagocytosis by host cells. It helps bacteria adhere to surfaces. Streptococcus mutants (cause of dental caries) initially binds to teeth by its glycocalyx ( EPS). Flagella Long filamentous appendages that propels bacteria. Motile bacteria use flagella ( singular - flagellum) to move Bacterial flagella are rigid, helical protein filaments that are attached to the cell Filaments composed of multiple subunits of a protein called flagellin . Flagellin aggregates to forms a helix around a hollow core. Flagella continued Arrangements monotrichous - single polar flagellum lophotrichous -twoor more flagella at one pole of cell amphitrichous - a tuft of flagella at each end of cell peritrichous - flagella distributed over the entire cell Salmonella with flagella Attachment of the Flagella Flagellum has three major sections: filament - which extends into the environment a hook - curved section connecting filament to the cell surface basal body - anchors the flagellum to the cell wall and membrane by means of disc shaped protein rings.
Background image of page 2
3 Bacterial Flagella Structure
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

Lecture7 - Lecture 7 Structural Features of Prokaryotic...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online