Cell motility

summary of (Cell motility) for health science students ...
By Abdoulwahab Mahdi Ali (Student)

1. Cell motility presentation By Abdoulwahab Mahdi Ali

2. What is the cell motility ?? Cellular motility  is the spontaneous movement of a cell from one location to another by consumption of energy..

3. Why Do Cells Move? Cell movement is required for a number of activities to occur within the body. White blood cells, such as neutrophils and macrophages must quickly migrate to sites of infection or injury to fight bacteria and other germs. Cell motility is a fundamental aspect of form generation in the construction of tissues,  organs and the determination of cell shape. In cases involving wound injury and repair, connective tissue cells must travel to an injury site to repair damaged tissue . In the cell cycle, movement is required for the cell dividing process of cytokinesis to occur in the formation of two daughter cells.

4. WBC chasing bacteria Cytokinesis

5. Movement Within Cells (cytoplasmic streaming) Not all cell movement involves the repositioning of a cell from one place to another. Movement also occurs within cells. Vesicle transportation ,  organelle migration , and  chromosome movement during mitosis are examples of types of internal cell movement.

6. Vesicle transportation   Involves the movement of molecules and other substances into and out of a cell. These substances are enclosed within vesicles for transportation. Endocytosis, pinocytosis, and exocytosis are examples of vesicle transportation processes. In  phagocytosis , a type of endocytosis, foreign substances and unwanted material are engulfed and destroyed by white blood cells. The targeted matter, such as a bacterium, is internalized, enclosed within a vesicle, and degraded by enzymes .

7. Organelle migration and chromosome movement This movement  occur during cell division. It ensures that each replicated cell receives the appropriate complement of chromosomes and organelles . Intracellular movement is made possible by motor  proteins ( Actin and myosin ) , which travel along cytoskeleton fibers. As the motor proteins move along microtubules, they carry organelles and vesicles with them.

8. Cell motility Ameboid movement Ciliary/flagella movement

9. Ameboid Flagella Cilia

10. Ameboid movement (Crawling) Ameboid movement  is one the common modes of locomotion in eukaryotic cells. It is a crawling-like type of movement accomplished by protrusion of cytoplasm of the cell involving the formation of pseudopodia  (false feet). One or more pseudopodia may be produced at a time depending on the organism, but all amoeboid movement is characterized by the movement of organisms with an amorphous form that possess no set motility structures. Movement occurs when the cytoplasm slides and forms a pseudopodium in front to pull the cell forward. it’s named A meboid because it finds a very definite expression in the amebae.

11. Continue For example, In epithelial repair, the cells free themselves and slide along Actively toward the depth of the wound. In an inflammatory process, Leucocytes wander out of the blood vessels ( diapedesis ) by active ameboid motion and progress toward the focus of infection .

12. Amoeba (Organism) movement The amoeba is the ideal material for the observation of this type Of motion. As shown by the classical studies, the cytoplasm Of the ameba has a clear ectoplasm without visible structure, which Expands considerably toward the end of the pseudopod (hyaline Cap), and a granular endoplasm which constitutes the greater part of its mass.

13. Continue In the endoplasm the author of our reference book (General cytology) distinguishes two parts: a peripheral part ( plasmagel ) which is immobile, and a central part ( plasmasol ) which flows along as the ameba progresses. T he internal endoplasm ( plasmasol ) flows into the pseudopodia and is followed by the rest of the cytoplasm .

14. Ciliary and flagella movement In contrast to ameboid movement which takes place on a solid substrate and involves a deformation or change in shape of the entire cytoplasm, ciliary movement is adapted to a liquid medium and is executed by contractile filaments called, Flagella , if they are few and long, cilia , if short and numerous.

15. Cilia A  cilium   (plural is  cilia ) is an organelle found in eukaryotic cells. Cilia are slender protuberances that project from the much larger cell body. There are two types of cilia   motile cilia and  non-motile

16. Motile cilia Larger eukaryotes, such as mammals, have motile cilia as well. Motile cilia are usually present on a cell's surface in large numbers and beat in coordinated waves . In humans, for example, motile cilia are found in middle ear and the lining of the  trachea (windpipe ), where they sweep mucus and dirt out of the lungs . In female mammals, the beating of cilia in the Fallopian tubes moves the ovum from the ovary to the  uterus. These hair-like threads move in a sweeping motion (rhythmic waving) to direct the flow of cells .

17. Cilia in fallopian tubes Cilia in middle ear Cilia in respiratory tract

18. Structure of cilia I nside cilia  is a microtubule-based cytoskeleton called the  A xoneme . The A xoneme of non-motile cilia typically has a ring of nine outer microtubule doublets (called a 9+0 axoneme ), and the axoneme of a motile cilium has two central microtubule singlets in addition to the nine outer doublets (called a 9+2 axoneme ). The axonemal cytoskeleton acts as a scaffolding for various protein complexes and provides binding sites for molecular motor proteins such as kinesin II, that help carry proteins up and down the microtubules .  On the outside of cilia is a membrane like the plasma membrane .

19. Structure of cilia

20. Dynein motor protein Dynein  is a family of cytoskeletal motor proteins that move   microtubules in  cells. They convert the chemical energy stored in ATP to mechanical work (Bend).

21. Flagella A  flagellum  is a whip-like structure that allows a cell to move. They are found in all three domains of the living world: bacteria archaea eukaryote Moves independently and exhibit andulatory motion (wave like motion). While all three types of flagella are used for locomotion, they are structurally very different .

22. 1- bacterial flagellum The bacterial flagellum is made up of the protein  flagellin . They are about 12-30 nm in diameter and 5-16 µm in length. They are responsible for the bacterial motility. Motility plays an important role in survival and the ability of certain bacteria to cause disease.

23. Types of bacterial flagella 1. Monotrichous – Single polar flagellum – Example:  Vibrio cholera 2. Amphitrichous – Single flagellum on both sides – Example:  Alkaligens faecalis 3. Lophotrichous – Tufts of flagella at one or both sides – Example:  Spirillum 4. Peritrichous – Numerous flagella all over the bacterial body – Example:  Salmonella Typhi

24. Parts of bacterial Flagella Parts of Flagella Each flagellum consists of three distinct parts-  Filament, Hook and Basal Body. The  filament  lies external to the cell. Hook  is embedded in the cell envelope. Basal Body  is attached to the cytoplasmic membrane by ring-like structures.

25. 2- Archaea flagella The archaeal flagellum is a unique, ( tail‐like) structure used for motility by single‐celled organisms belonging to the domain Archaea. These intricate protein assemblies extend from the cell surface, rotating to generate thrust that propels the organism. Although archaeal flagella are functionally similar to the flagella found on bacteria, they differ significantly in structure

26. 3- Eukaryote flagella A eukaryotic flagellum is a bundle of nine fused pairs of  microtubule doublets surrounding two central single microtubules. The so-called (9  +  2) structure is characteristic of the core of the eukaryotic flagellum called an  axoneme . (Same as motile cilia). Structure and the mechanism of eukaryotic flagella is like motile cilia only fewer in number and longer in length.

27. Why cell motility is important ??

28. Any questions ????!!!