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Similarities between Pro- and Eukaryotes
- Macromolecules - DNA, Proteins, Lipids, Polysaccharides
- Metabolic reactions
- Cell Membranes contain everything
- Homology of housekeeping genes
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Differences of Prokaryotic cells
- DNA is often a single, non-enclosed chromosome
- Divide by Binary fission
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Differences of Eukaryotic cells
- Multiple linear dsDNA chromosomes
- DNA associated with histones (and other proteins)
- Many membrane-bound organelles
- Enclosed DNA (nucleus)
- Division by mitosis
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Domains included as prokaryotes
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Organelles found in prokaryotes
- Cell walls
- Flagellum
- Pili and Fimbriae
- Inclusions
- Gas Vacuole
- Capsule and Slim layers
- Endospore
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Kingdoms included under eukarya
Protozoa, Fungi, Algae, Animals
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Cell morphologies
Coccus, Bacillus, Pleomorphic, Spirillum, Mycelial, Stalked, Plates, Star
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What governs cell size
Metabolic logistics/requirements (surface area to volume)
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Mycoplasma (smallest cells)
0.1μm - 0.2μm
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Sizes of Bacterial and Eukaryote cells (generally)
- Bacteria: 1μm - 10μm
- Eukarya: 10μm - 100μm
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Largest prokaryotes
- Epoluposcium fishelsoni
- Thiomargarita namibiensis
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Nanochlorum eukaryotum
Small eukaryote
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Functions of the plasma membrane
- Establishing a concentration gradient
- Selective permeability
- Differentiate bacteria and archaea
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Who proposed the Fluid Mosaic Model?
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Bifacial
- Sidedness
- Feature of membranes
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Plasma membrane thickness
6-8nm
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Membrane components
Lipids, Proteins Carbohydrates
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Role of lipids in the membrane
Basic backbone, forming an amphipathic bilayer
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Types of membrane protein
- Integral (70% - 80%)
- Peripheral (20% - 30%)
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Roles of membrane proteins
- Transport
- Enzymes
- Receptors
- Intracellular junctions
- Cell-to-cell recognition
- Metabolism
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Differences between bacterial and eukaryotic membranes
- Bacteria lack sterols
- Extensive membrane folding (greater metabolic activity)
- Microdomians (lipid rafts)
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Bacterial phospholipid structure
Glycerol, with two attached fatty acids by ester bonds
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Example bacterial fatty acids
- Palmitic acid
- Stearic acid
- Unbranched, 16-18 carbons; saturated and/or unsaturated
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FAME
Fatty acid methyl ester analysis
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Sterol basic structure
Four interconnected rings
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Mycoplasma sterol aquisition
From eukaryote membranes
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Archeal membrane lipids
- Not phospholipids
- Ether linkages to glycerol
- Branched or ring-containing fatty acids
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Monolayers
- Diglycerol tetraether
- Found in archaea/thermophiles
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