cell biology flagella motility ppt by Neha

cell biology Neha yadav 2.pptx

1. A Seminar Topic on – Flagella motility Presented by - Neha Yadav (M.Sc.1 st Sem) Subject – Biotechnology Course Title – Cell Biology Course Code – BTC101 Submitted To – Miss Anuradha Singh College – Holy Cross women’s College ambikapur

2. Contents Introduction Flagellar Arrangments Types of Flagellar Structure of flagella Mechanism of Flagella Movement Difference Between Eukaryotic and Prokaryotic Flagella Function of Flagella References

3. Introduction Flagella are microscopic hair-like structures involved in the locomotion of a cell. The word “flagellum” means “whip”. The flagella have a whip-like appearance that helps to propel a cell through the liquid. Some special flagella are used in few organisms as sensory organs that can sense changes in pH and temperature. Size: thin 15-20nm in diameter.

4. The flagella is a helical structure composed of flagellin protein. The flagella structure is divided into three parts: Basal body Hook Filament Basal Body It is attached to the cell membrane and cytoplasmic membrane. It consists of rings surrounded by a pair of proteins called MotB. The rings include: L-ring: Outer ring anchored in the lipopolysaccharide layer and found in gram +ve bacteria. P-ring: Anchored in the peptidoglycan layer. C-ring: Anchored in the cytoplasm M-S ring: Anchored in the cytoplasmic membrane Hook It is a broader area present at the base of the filament. Connects filament to the motor protein in the base. The hook length is greater in  gram +ve bacteria . Filament Thin hair-like structure arising from the hook Bacterial Flagella Structure

5. Fig : Flagella Structure

6. L and P are absent in gram positive cells

7. Types of Flagella 1 •Bacterial Flagella 2• Eukaryotic flagella - Bacterial flagella are helically coiled structures that are slightly longer than the archaeal and eukaryotic flagella. - Flagella in eukaryotes commonly occur in many algae and some animal cells like sperms.

8. Mechanism of Flagella motility At the base surrounding the inner ring (M-S and C ring) there is a series of protein called Mot protein. A final set of protein called Fli protein function as motor switch. The flagella motor rotates the filament as a turbine causing movement of the cell in the medium. The movement of flagella results from rotation of basal body which is similar to the movement of the shaft of an electric motor.

9. A turning motion is generated between S-ring and M ring. S-ring acts as starter while M ring acts as roter. The basal body as a whole give a universal joint to the cell and allows complete rotation of hook and filament. Flagella moves the cell by rotating the flagella about the basal body. Rotation of flagella is either clockwise •A proton motive force is used to generate torque . •The channel created by MotA and MotB proteins allow protons to move across the plasma membrane from outside to inside. • They move to the charge and pH gradient . • movement releases energy that is used to rotate the flagellum .

10. Fig. - FLAGELLA MOVEMENT IN BACTERIA

11. 1 . Movement 2 . Type of Proteins 3 . Size 4 . Presence of Microtubules 5 . Membranous Sheath Difference Between Eukaryotic and Prokaryotic flagella

12. Function of Flagella Movements Sensation Signal transduction Few eukaryotes use flagellum to increase reproduction rates. Recent researches have proved that flagella are also used as a secretory organelle. For eg., in Chlamydomonas

13. 1 • Karp Genald book of cell and molecular biotechnology , publisher – John wiley & sons,INC , publishe year – 1996 , Chapter 9 ,the cytoskeleton and cell motility , page no. 357 – 393 . 2 . Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 19.4, Cilia and Flagella: Structure and Movement. Available from:  https://www.ncbi.nlm.nih.gov/books/NBK21698/ 3 . Nikhil A. Thomas, Sonia L. Bardy, Ken F. Jarrell, The archaeal flagellum: a different kind of prokaryotic motility structure,  FEMS Microbiology Reviews , Volume 25, Issue 2, April 2001, Pages 147–174,  https://doi.org/10.1111/j.1574-6976.2001.tb00575.x Reference