Movement of an entire cell in relation to its surroundings. Involves pseudopodium and ATP. Mechanism • formation of new cell membrane & exocytosis at one end • Attachment of pseudopodium to tissues Receptor proteins • Absorption of the membrane & endocytosis in mid & rear portions • Detachment of receptor proteins
Cells that exhibit amoeboid motion • WBC • Fibroblasts • Embryonic cells • Amoeba Control of amoeboid motion • Chemotaxis Positive Negative
• Migration of embryonic cells during development• Invasion of tissues by white blood cell to fight infection• The migration of cells involved in wound healing• Spread of cancer cells during the metastasis of malignant tumors
Cilia and Flagella anatomy!This is the 9 + 2 pattern characteristic of nearly all flagella and cilia.
Cilia move in waves: metachronal waves. Undulatory movementPower strokeor oar likeaction Flagellar movement
Whiplike movement of cilia on the surfaces of cells A sharp pointed hair projecting 2- 4micrometers from the surface of the cell.
Covered by an outcropping of cell membrane Supported by 11 microtubules, 9 double tubules at the periphery and 2 single tubules down the center. Each cilium is an outgrowth of a structure that lies immediately beneath the cell membrane, called basal body of the cilium
Allthe tubules are linked to one another by a complex of protein cross linkages, together called the axoneme. Multiple protein arms composed of the protein dynein (having ATPase activity) project outward from each double tubule ATP and appropriate magnesium and calcium concentration required.
Sudden fast forward whip like stroke Slow backward stroke An effective way of pushing the fluid in the direction of forward stroke.
Direction of swimming (a) Motion of flagella 5 µmDirection of organism’s movementPower stroke Recovery stroke (b) Motion of cilia 15 µm
How dynein “walking” moves flagella and cilia: − Dynein arms alternately grab, move, and release the outer microtubules • Protein cross-links limit sliding • Forces exerted by dynein arms cause doublets to curve, bending the cilium or flagellum
Fig. 6-25 Microtubule doublets ATP Dynein protein (a) Effect of unrestrained dynein movement ATP Cross-linking proteins inside outer doublets Anchorage in cell (b) Effect of cross-linking proteins 1 3 2 (c) Wavelike motion
Fig. 6-25a Microtubule doublets ATP Dynein protein (a) Effect of unrestrained dynein movement
Fig. 6-25b ATP Cross-linking proteins inside outer doublets Anchorage in cell (b) Effect of cross-linking proteins 1 3 2 (c) Wavelike motion
CELLS EXHIBITING CILIARY MOVEMENT 1- Respiratory airways 2- Uterine tubes of the female reproductive tract.