Cell structure and function
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Cells contain organelles that carry out specific functions. The cytoplasm contains organelles like mitochondria, which produce energy, and the endoplasmic reticulum and Golgi apparatus, which process and package proteins and lipids. The cytoskeleton is made of microtubules, microfilaments, and intermediate filaments that help maintain cell shape and allow movement. The nucleus houses the cell's DNA and directs protein production. Organelles are surrounded by membranes and transport materials throughout the cell.
Cell structure and function
- 1. Cells are the Structural and Functional Units of an Organism
- 3. Cells are Diverse in Size, Shape, and Length
- 4. Parts of a Cell: Nucleus, Cytoplasm, and Plasma Membrane
- 5. The Cytoplasm The major functional area of the cell. Consists of: Cytosol Organelles Inclusions
- 6. Inclusions: Stored Nutrients Glycogen Lipid (brown fat)
- 7. Melanin Secretory Granules Substantia Nigra Pancreas
- 9. Mitochondria The site of ATP production. Metabolically active cells have more mitochondria. Are self-replicating. May have evolved from purple bacteria.
- 10. Ribosomes Composed of protein and rRNA. May be free in the cytoplasm or bound to endoplasmic reticulum.
- 15. The Golgi Apparatus Plasma Cells
- 16. Lysosomes Sites of digestion. Lysosomal enzymes are produced by the RER. The lysosomal membrane has special adaptations. Lysosomes function in: 1. Digestion of ingested particles 2. Digestion of worn-out organelles 3. Metabolism of stored glycogen Lysosomal rupture results in autolysis.
- 17. Lysosomes Phagocytosis
- 18. Peroxisomes Convert free radicals to H2O2 Required for detoxification Self-replicate
- 19. Peroxisomes
- 20. The Cytoskeleton
- 21. Cytoskeletal Elements Microtubules: * Hollow tubes formed by proteins called tubulins * Comprise the centrosome and other structures (e.g., cilia & flagella) * Variable stability (mitotic spindle is labile) * Maintain cell shape and rigidity
- 22. Structure of a Microtubule
- 23. Cilia Basal bodies control the assembly of the axoneme.
- 25. Cytoskeletal Elements Microfilaments: consist of thin strands of actin form the core of microvilli, allow amoeboid movement, produce the cleavage furrow most highly developed in muscle cells labile are attached to the cytoplasmic side of the plasma membrane
- 26. Cytoskeletal Elements Intermediate Filaments: Intermediate in size Have tensile strength Most stable Specific names in certain cell types (see table 2-4)
- 27. The Nucleus The largest organelle and has 3 regions: nuclear membrane nucleolus – protein and rRNA chromatin – DNA and histone proteins euchromatin - active (vesiculate nucleus) heterochromatin - inactive (pachychromatic nucleus)
- 28. The Nucleus
- 29. Nuclear Pores 200,000 X 48,000 X
- 30. Nucleosomes – the fundamental units of chromatin
- 31. Intracellular Pigments * Endogenous or exogenous (environmental) * Exogenous pigments include carbon and other dusts * Endogenous pigments: lipofuscin, melanin, hemosiderin. Apoferritin + iron = ferritin hemosiderin = large amounts of ferritin
- 32. Endogenous Intracellualr Pigments - Hemosiderin
- 33. Exogenous Intracellular Pigments Silicosis Asbestosis
- 34. Endogenous Intracellular Pigments Lipofucsin