Prokaryotes, Eukaryotes, etc.

1. Prokaryotes andEukaryotes

2. Classification of Organisms

4. Major Difference

6. simple, single-celled organisms

7. distinct cell wals containing peptidoglycan layer

8. No true nucleus (only nucleoid)

10. MORPHOLOGY Prokaryotes exhibit a variety of shapes Other shapes Coccobacillus Short round rod Vibrio Curved rod Spirillum Spiral shaped Spirochete Helical shape Pleomorphic Bacteria able to vary shape

11. MORPHOLOGY Arrangement: Division along a single plane may result in pairs or chains of cells Pairs = diplococci Example: Neisseriagonorrhoeae Chains = streptococci Example: species of Streptococcus

13. General Structure

14. General Structure of a Prokaryotic Cell

15. CELL APPENDAGES

16. FLAGELLA Some bacteria have protein appendages Not essential for life Aid in survival in certain environments They include Flagella Pili

17. FLAGELLA Flagella Long protein structure Responsible for motility Use propeller like movements to push bacteria Can rotate more than 100,00 revolutions/minute 82 mile/hour Some important in bacterial pathogenesis H antigen useful in distinguishing among serovras of gram negative bacteria

18. FLAGELLA Flagella structure has three basic parts Filament Extends to exterior Made of proteins called flagellin Hook Curved sheath Connects filament to cell Basal body Anchors flagellum into cell wall and membrane

19. Figure 4.8b

20. FLAGELLAR ARRANGEMENTS 1. Monotrichous – single flagellum at one end 2. Lophotrichous – small bunches arising from one end of cell 3. Amphitrichous – flagella at both ends of cell 4. Peritrichous – flagella dispersed over surface of cell, slowest

21. FLAGELLAR ARRANGEMENTS

22. FLAGELLA

23. Motile Cells

24. Axial Filaments Endoflagella In spirochetes Anchored at one end of a cell Rotation causes cell to move

25. PILI Rigid tubular structure made of pilinprotein Found only in Gram negative cells Functions Sexual pili—joins bacterial cells for DNA transfer (conjugation) Common pili—adhesion

26. FIMBRAE Fine hairlike bristles from the cell surface Function in adhesion to other cells and surfaces

27. CELL ENVELOPE

29. GLYCOCALYX Coating of molecules external to the cell wall, made of sugars and/or proteins 2 types slime layer - loosely organized and attached capsule – highly organized, tightly attached Functions attachment inhibits killing by white blood cells receptor

31. Streptococcus mutansuses sucrose to synthesize a biofilm

33. CELL WALL Bacterial cell wall Rigid structure Surrounds cytoplasmic membrane Determines shape of bacteria Holds cell together Prevents cell from bursting Unique chemical structure Distinguishes Gram positive from Gram-negative

34. GRAM POSITIVEGRAM NEGATIVE

35. GRAM POSITIVE WALL Rigidity of cell wall is due to peptidoglycan (PTG) Compound found only in bacteria Basic structure of peptidoglycan Alternating series of two subunits N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM) Joined subunits form glycan chain Glycan chains held together by string of four amino acids Tetrapeptide chain

37. As many as 30

38. Regardless of thickness, peptidoglycan is permeable to numerous substancesTeichoicacid component of peptidoglycan; composed of glycerol and phosphate Lipoteucholic acid is attached to the lipids of cytoplasmic membrane Gives cell negative charge

39. GRAM POSITIVE WALL

40. GRAM POSITIVEGRAM NEGATIVE

41. GRAM NEGATIVE WALL More complex than Gram+ Only contains thin layer of peptidoglycan Peptidoglycan sandwiched between outer membrane and cytoplasmic membrane Region between outer membrane and cytoplasmic membrane is called periplasm or periplasmic space Gel-like area Most secreted proteins contained here

43. Constructed of lipid bilayerMuch like cytoplasmic membrane but outer layer made of lipopolysaccharides and phospholipids Outer membrane also called the lipopolysaccharide layer or LPS layer LPS severs as barrier to a large number of molecules Small molecules or ions pass through channels called porins Specific channel proteins are present

44. GRAM NEGATIVE WALL O-specific polysaccharide chain Directed away from membrane Opposite location of Lipid A Used to identify certain species or strains E. coli O157:H7 refers to specific O-side chain Lipid A Portion that anchors LPS molecule in lipid bilayer Plays role in recognition of infection Molecule present with Gram negative infection of bloodstream--endotoxin

45. GRAM NEGATIVE WALL

47. Gram-Positive Membrane

48. Gram-Negative Outer Membrane

50. Binds proteins involved in cell wall synthesis

51. Prevents cross-linking of glycan chains by tetrapeptides

52. More effective against Gram positive bacterium

53. Due to increased concentration of peptidoglycans

56. CELL WALL Differences in cell wall account for differences in staining Characteristics: Gram-positive bacterium retain crystal violet-iodine complex of Gram stain Gram-negative bacterium lose crystal violet-iodine complex

57. The Gram Stain

58. CELL WALL Some bacterium naturally lack cell wall Mycoplasma Bacterium causes mild pneumonia Have no cell wall Antimicrobial directed towards cell wall ineffective Sterols in membrane account for strength of membrane

59. CYTOPLASMIC MEMBRANE Cell (Cytoplasmic) membrane Delicate thin fluid structure Surrounds cytoplasm of cell Defines boundary Serves as a semi permeable barrier Barrier between cell and external environment

60. CELL MEMBRANE Structure is a lipid bilayer with embedded proteins Bilayer consists of two opposing layers Layer composed of phospholipids Each contains a hydrophilic phosphate head and hydrophobic fatty acid tail

61. CELL MEMBRANE Membrane is embedded with numerous protein More that 200 different proteins Proteins function as receptors, channels proteins, and transport proteins Provides mechanism to sense surroundings Proteins are not stationary Constantly changing position Called fluid mosaic model

62. CYTOPLASM

63. CYTOPLASM Dense gelatinous solution of sugars, amino acids, & salts 70-80% water Serves as solvent for materials used in all cell functions

64. STRUCTURES WITHIN CYTOPLASM Bacterial cells have variety of internal structures Some structures are essential for life Chromosome Ribosome Others are optional and can confer selective advantage Plasmid Storage granules Endospores

65. INTERNAL STRUCTURES Chromosome Resides in cytoplasm In nucleoid space Typically single chromosome: protein and DNA Circular double-stranded molecule Contains all genetic information Plasmid Circular DNA molecule Generally 0.1% to 10% size of chromosome Extrachromosomal Independently replicating Encode characteristic Potentially enhances survival Antimicrobial resistance Tolerance to toxic metals

66. INTERNAL STRUCTURE Ribosome Involved in protein synthesis Composed of large and small subunits Units made of protein 40% and ribosomal RNA 60% Prokaryotic ribosomal subunits Large = 30S Small = 50S Small than eukaryotic ribosomes Difference often used as target for antimicrobials

67. INTERNAL STRUCTURES Storage granules Accumulation of polymers Synthesized from excess nutrient Example = glycogen Excess glucose in cell is stored in glycogen granules Gas vesicles Small protein compartments Provides buoyancy to cell Regulating vesicles allows organisms to reach ideal position in environment

68. INTERNAL STRUCTURES Endospores Dormant cell types Produced through sporulation Theoretically remain dormant for 100 years Resistant to damaging conditions Heat, desiccation, chemicals and UV light Vegetative cell produced through germination Germination occurs after exposure to heat or chemicals Germination not a source of reproduction Common bacteria genus that produce endospores include Clostridium and Bacillus

70. Inclusions Metachromatic granules (volutin) Polysaccharide granules Lipid inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Phosphate reserves Energy reserves Energy reserves Energy reserves Ribulose 1,5-diphosphate carboxylase for CO2 fixation Protein covered cylinders Iron oxide (destroys H2O2)

71. Inclusions

72. Archaea primitive prokaryotes extermophiles lacks peptidoglycan in their cell wall ether-linked membrane lipids

73. Phylogenetic Tree of Archaea

74. Archaea Morphology Basic Archaeal Shapes : At far left, Methanococcusjanaschii, a coccus form with numerous flagella attached to one side. At left center, Methanosarcinabarkeri, a lobed coccus form lacking flagella. At right center, Methanothermusfervidus, a short bacillus form without flagella. At far right, Methanobacteriumthermoautotrophicum, an elongate bacillus form.

75. Archaea Morphology Membrane lipids ether bonds link glycerol to hydrocarbon side chains lacks fatty acids side chains composed of repeating isoprene units major lipid components: glycerol dietherand diglycerolteraether lipid monolayer

76. Archaea Morphology

77. Archaea Morphology Cell Wall lacks outer membrane pseudomurein: N-acetylglucosamine + N –acetyltalosaminuronic acid β-1,3 glycosidic linkage L-amino acids Polysaccharide cell walls Methanosarcina: glucose, glucuronic acid, uronic acid galactosamine, and acetate Halococcus: same as Methanosarcinacell wall + Sulfate ions

78. Archaea Morphology Cell Wall S-layers: paracrystalline surface layers proteins or glycoprotein arranged in various symmetries Functions: structural support interface btwn cell and its environment selective sieve retain proteins near cell surface

79. Archaea Morphology Other Cell Walls Natronococcus:haloalkalophilic species of Archaea glycoprotein cell wall contains L-glutamate as a single type of amino acid linking glucose and glucose derivatives

80. Archaea Crenarchaeaota: most thermophilicarchaea are found in this group. They use sulfur compounds as electron donors or as acceptors. Not all are thermophilic. Euryarcheota: methanogens, halophiles, thermophiles. Korarcheota; found in hot springs. None have been grown in pure culture.

82. The hot springs of Yellowstone National Park, USA, were among the first places Archaea were discovered. At left is Octopus Spring, and at right is Obsidian Pool. Each pool has slightly different mineral content, temperature, salinity, etc., so different pools may contain different communities of archaeans and other microbes. The biologists pictured above are immersing microscope slides in the boiling pool onto which some archaeans might be captured for study.

83. Salt-lovers : immense bloom of a halophilic ("salt-loving") archaean species at a salt works near San Quentin, Baja California Norte, Mexico. This archaean, Halobacterium, also lives in enormous numbers in salt ponds at the south end of San Francisco Bay; interested residents of this area should take the Dumbarton Bridge for the best views.

84. Eukarya Figure 4.22a

85. Flagella and Cilia Figure 4.23a–b

86. Microtubules Tubulin Nine pairs + two arrangements Figure 4.23c

87. Cell Wall Cell wall Plants, algae, fungi Carbohydrates Cellulose, chitin, glucan, mannan Glycocalyx Carbohydrates extending from animal plasma membrane Bonded to proteins and lipids in membrane

88. Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Sterols Glycocalyx carbohydrates

89. Plasma Membrane Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport Endocytosis Phagocytosis: Pseudopods extend and engulf particles. Pinocytosis: Membrane folds inward bringing in fluid and dissolved substances.

90. Eukaryotic Cell Cytoplasm membrane:Substance inside plasma and outside nucleus Cytosol: Fluid portion of cytoplasm Cytoskeleton: Microfilaments, intermediate filaments, microtubules Cytoplasmic streaming: Movement of cytoplasm throughout cells

91. Organelles Membrane-bound Nucleus: Contains chromosomes ER: Transport network Golgi complex: Membrane formation and secretion Lysosome: Digestive enzymes Vacuole: Brings food into cells and provides support Mitochondrion: Cellular respiration Chloroplast: Photosynthesis Peroxisome: Oxidation of fatty acids; destroys H2O2

92. Eukaryotic Cell Not membrane-bound Ribosome: Protein synthesis Centrosome: Consists of protein fibers and centrioles Centriole: Mitotic spindle formation

93. Nucleus Figure 4.24

94. Endoplasmic Reticulum Figure 4.25

95. Ribosomes 80S Membrane-bound Attached to ER Free In cytoplasm 70S In chloroplasts and mitochondria

96. Golgi Complex Figure 4.26

97. Lysosomes and Vacuoles Figure 4.22b

98. Mitochondrion Figure 4.27

99. Chloroplast Figure 4.28

100. Endosymbiotic Theory Figures 10.2, 10.3

101. Endosymbiotic Theory UN 4.1