Cells
- 2. Outline Cell Theory Cell Size Prokaryotic Cells Eukaryotic Cells Organelles Containing DNA Endosymbiosis Plant Cells Animal Cells
- 3. Cell Characteristics Genetic material single circular molecule in prokaryotes double helix located in nucleus in eukaryotes Cytoplasm fills cell interior Plasma membrane encloses the cell
- 5. Cell Theory All organisms are composed of one or more cells. Cells are the smallest living units of all living organisms. Cells arise only by division of a previously existing cell.
- 6. Cell Size Most cells are relatively small because as size increases, volume increases much more rapidly. longer diffusion time
- 7. Visualizing Cells Resolution - minimum distance two points can be apart and still be distinguished as two separate points Compound microscopes - magnify in stages using multiple lenses Transmission electron microscope - electrons transmitted through specimen Scanning electron microscope - electrons beamed onto surface of the specimen
- 9. Prokaryotic Cells Simplest organisms Cytoplasm is surrounded by plasma membrane and encased in a rigid cell wall composed of peptidoglycan. no distinct interior compartments gram-positive gram-negative Susceptibility of bacteria to antibiotics depends on cell wall structure.
- 10. Prokaryotic Cells Some use flagellum for locomotion threadlike structures protruding from cell surface
- 11. Eukaryotic Cells Characterized by compartmentalization by an endomembrane system, and the presence of membrane-bound organelles. central vacuole vesicles chromosomes cytoskeleton cell walls
- 12. Nucleus Repository for genetic material Nucleolus - region of intensive ribosomal RNA synthesis Surface of nucleus bound by two phospholipid bilayer membranes nuclear membrane
- 13. Nucleus
- 14. Chromosomes DNA of eukaryotes is divided into linear chromosomes. exist as strands of chromatin, except during cell division associated with packaging histones, packaging proteins nucleosomes
- 15. Endomembrane System Compartmentalizes cell, channeling passage of molecules through cell’s interior. Endoplasmic reticulum Rough ER - studded with ribosomes Smooth ER - few ribosomes
- 16. Endomembrane System Golgi apparatus collection of Golgi bodies collect, package, and distribute molecules synthesized at one location in the cell and utilized at another location
- 17. Endomembrane System Vesicles Lysosomes - membrane-bound digestive vesicles Microbodies - enzyme-bearing, membrane-enclosed vesicles. Peroxisomes - contain enzymes that catalyze the removal of electrons and associated hydrogen atoms
- 18. Ribosomes Ribosomes are RNA-protein complexes composed of two subunits that join and attach to messenger RNA. site of protein synthesis assembled in nucleoli
- 19. Organelles With DNA Mitochondria bounded by exterior and interior membranes interior partitioned by cristae Chloroplasts have enclosed internal compartments of stacked grana, containing thylakoids found in photosynthetic organisms
- 20. Endosymbiosis Endosymbiotic theory suggests engulfed prokaryotes provided hosts with advantages associated with specialized metabolic activities.
- 21. Cytoskeleton Network of protein fibers supporting cell shape and anchoring organelles Actin filaments cell movement Microtubules centrioles Intermediate filaments
- 22. Cytoskeleton
- 23. Plant Cells Central vacuole often found in the center of a plant, and serves as a storage facility for water and other materials Cell wall primary walls middle lamella secondary walls
- 24. Plant Cell
- 25. Animal Cells Animal cells lack cell walls. form extracellular matrix provides support, strength, and resilience
- 26. Summary Cell Theory Cell Size Prokaryotic Cells Eukaryotic Cells Organelles Containing DNA Endosymbiosis Plant Cells Animal Cells