Structure and function of cell components

1. Structure and function of cell components Carbohydrates Lipids Proteins Nucleic Acids Membranes Cytoskeleton

2. Structure of cytoskeleton • Cytoskeleton is found in all eukaryote cells • It is anchored in the cell membrane via membrane proteins • It is composed of 3 types of fibre microfilaments

3. Microtubules • Found in all eukaryote cells • Hollow tubes made of the protein tubulin • Radiate from the MTOC (microtubule organising centre), stretch to plasma membrane • MTOC changes length of microtubule by assembling and disassembly ends • Microtubules can be assembled and disassembled rapidly • Components of microtubules become spindle fibres during cell division

4. Microtubules cont…. • Function • Provide structural support by resisting compression • Have a role in organelle movement • Separate chromatids during cell division • Components of cilia, flagella and centrioles

5. Microfilaments • Made of actin protein • Present throughout the cell, but most common just inside the plasma membrane • Readily assembled and disassembled • Function • Involved in cell membrane movements e.g. Endocytosis / Phagocytosis • Give cell shape • Are part of the contractile ring that forms the two daughter cells during cytokinesis of animal cells

6. Intermediate filaments • Mostly made of keratin proteins • Not found in all cells • Probably permanent (cannot be assembled and disassembled) although cells may be able to regulate length • Function • Very stable tough fibres providing cell support • Abundant in areas of a cell subject to mechanical stress

7. Learning Activities • Read and take notes from DART pg (58-60) • Scholar 5.3 • Look back at the role of MTOCs and spindle fibres in cell division (cell cycle notes) • Create a list of cytoskeleton functions and remember it • Advanced Higher Questions