biology notes

  CYTOSKELETON DEFINITION; CYTOSOL CONTAINS CYTOSKELETAL FABRIC FORMED OF; 👆 MICROFILAMENT 👆 MICROTUBULE 👆 INTERMEDIATE FILAMENT MAIN PROTEIN; THE MAIN PROTEINS THAT ARE PRESENT IN CYTOSKELETON ARE  TUBULIN,  ACTIN, MYOSIN, TROPOMYOSIN AND OTHERS WHICH ARE ALSO PRESENT  IN MUSCLES. SPECIAL ORGANELLES; SEVERAL CELL ORGANELLES ARE DERIVED FROM SPECIAL ASSEMBLIES OF MICROTUBULES, LIKE CILIA, FLAGELLA, BASAL BODIES AND  CENTRIOLES. TYPES; MICROTUBULES; MICROTUBULES ARE LONG, UNBRANCHED, SLENDER TUBULIN  PROTEIN STRUCTURE. FUNCTION; ONE VERY IMPORTANT FUNCTION OF MICROTUBULE IS THEIR ROLE IN  THE ASSEMBLY AND DISASSEMBLY OF SPINDLE STRUCTURE DURING  MITOSIS. MICROFILAMENTS; MICROFILAMENT ARE CONSIDERABLY MORE SLENDER CYLINDRES MADE  UP OF CONTRACTILE ACTIN PROTEIN, LINKED TO THE INNER FACE OF  PLASMA MEMBRANE.  FUNCTION; THEY ARE INVOLVED IN INTERNAL CELL MOTION. INTERMEDIATE FILAMENT; THEY HAVE DIAMETER IN BETWEEN THOSE OF MICR...

CENTRIOLES DEFINITION; ANIMALS AND MANY UNICELLULAR ORGANISMS HAVE HOLLOW  AND CYLINDRICAL ORGANELLES KNOWN AS CENTRIOLES. LOCATION;  ANIMALS CELLS, AND CELLS OF SOME MICROORGANISMS AND  LOWER PLANTS CONTAIN TWO CENTRIOLES LOCATED NEAR THE  EXTERIOR SURFACE OF THE NUCLEUS .  CONSIST OF; IN CROSS SECTION EACH CENTRIOLE CONSISTS OF A CYLINDRICAL ARRAY OF NINE MICROTUBULES . HOWEVER, EACH OF THE NINE MICROTUBULES IS FURTHER COMPOSED  OF THREE TUBULES. PLACED ON;  THE TWO CENTRIOLES  ARE USUALLY PLACED AT RIGHT ANGLE TO  EACH OTHER.   WORKING; JUST BEFORE A CELL DIVIDES, ITS CENTRIOLES DUPLICATE AND ONE  PAIR MIGRATES TO THE OPPOSITE SIDE OF THE NUCLEUS. THE SPINDLE  THEN FORMS BETWEEN THEM. THEY ARE ABSENT IN HIGHER PLANTS. FUNCTION;  CENTRIOLES PLAY IMPORTANT ROLE IN THE FORMATION OF CILIA  AND FLAGELLA. THE END