Prokaryotic and Eukaryotic Cells Two Main Classes of Cells Prokaryotic (Bacteria and Archaea) Pro = Before ; Karyon = Kernel No nucleus, DNA coiled up inside cell Eukaryotic (Everything else) Eu = True DNA inside membrane bound organelle inside cell, the nucleus 3 Domains of Life Eukaryotic Cell (non bacterial) Prokaryotic Cell (bacteria) Size Differences Cell Size: Prokaryotes and eukaryotic cell 1
Prokaryotic Diversity: K. Monera 4000 described species Estimated range 400,000-4 million sp. Minimal structural diversity Tremendous metabolic diversity Ecological roles and pathogenesis Prokaryotic Cell Bacterial Size, Shape and Arrangement Coccus Bacillus Spiral Prokaryotic Cell The Capsule: Frederick Griffith, 1928 Enhances virulence: attachment and resistance Forms the foundation of biofilms Gram staining: A clinical tool for distinguishing cell wall composition (Gram-positive and gram-negative bacteria) 2
Common bacterial CELL WALL structures as revealed by Gram staining: Bacterial Motility: Flagella Gram positive: thick peptidoglycan cell wall Gram negative: thin peptido. wall + outer memb. Bacterial Growth: Binary fission a simple division process Movie 1 Movie 2 Ecological Importance Bacteria and Cyanobacteria Nutrient Cycling: Decomposers Carbon fixation Nitrogen fixation Others Symbioses: Mutualistic: +/+ Commensalistic: +/o Parasitic: +/- Foreign pathogens Opportunistic pathogens Prokaryotes Low morphological diversity (how they looks) HUGE metabolic diversity! All organisms can be divided into either of two major groups based upon their pattern of cell structure: Characteristic Prokaryotic Cell Eukaryotic Cell size ave. size 1-10 µm ave. size 10-100 µm nucleus nucleoid membrane bound (no membrane) chromosomes single circ. loop of naked DNA linear, arranged with histones in pairs organelles absent present, vary with cell function ribosomes present as smaller 70S form present as larger 80S form flagella Solid core made of flagellin 9+2 arrangement of microtubules cell wall present in most sp. as peptidoglycan absent or different in composition cell reproduction binary fission mitosis and sexual reproduction 3
Animal Cell Plant Cell Evolution of Eukaryotic Cells Limits of the P.M. Surface area revisited Differentiation of P.M. Formation of Organelles Compartmentalized Reaction centers Increase Membrane Surface area More efficient Metabolism Increase DNA which means? Leads to Eukaryotic cells Eukaryotic Cell Structure: The Factory Plant and Animal Cell Structure Nucleus: the control center Cytoplasm and Ribosomes: site of protein synthesis Endoplasmic Reticulum: plumbing, lipid and protein synthesis Golgi Apparatus and the secretory pathway Lysosomes: digestive activity Chloroplasts and Mitochondria: food and ATP energy Vacuoles: storage/digestion Cytoskeleton: structure and movement Plant Cell Wall: structure, osmosis and turgor pressure Family Photos-- structural and functional specializations Animal Cell The Nucleus Chromatin= DNA + proteins Nucleolus= site of ribosome production Endomembrane system Interrelated membrane network inside of cell 4
The Nucleus and Protein Synthesis Ribosomes The real Ribosomes Protein Synthesis Free- endogenous proteins Bound- secretory and membrane bound proteins The Endoplasmic Reticulum How the Rough ER Works Huge Surface Area General functions Rough endoplasmic reticulum (RER) Makes more membranes, Modifies proteins Smooth endoplasmic reticulum (SER) Makes lipids, steroids, hormones, etc Detox in the liver Storage 5
The Golgi Apparatus ER and Golgi complex Storage, refinement, and shipping of ER products Works in partnership with ER Lysosomes Figure 4.10 Lysosome formation Sacks of digestive enzymes which break down molecules and organelles in the cells Digest food, fight invaders, clean house ph of 5 Apoptosis Disorders Vacuoles Sacks which can store enzymes, proteins, water, and cellular byproducts, waste. Plants cells often have large Central Vacuole which holds water and other stuff Vacuoles also transport things from one organelle to another within the cell Plant Cell 6
Vacuoles Mitochondria and Chloroplasts Role in Energy Transformation Photosynthesis Cellular respiration Evolution Endosymbiosis Theory Most of the living world depends on chloroplasts for its energy! Two membranes on outside Complex membrane structure on inside The Chloroplast The Mighty Mitochondria Sites of cellular respiration and ATP synthesis The Cytoskeleton The skeleton, muscles and highway of a cell Cilia and Flagella 7
A comparison of the beating of flagella and cilia Support and Joining of Cells Support and Joining of Cells 8