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BACTERIAL MORPHOLOGY CON’T Plasma (cytoplasmic) membrane

BACTERIAL MORPHOLOGY CON’T Plasma (cytoplasmic) membrane. Phospholipid bilayer (Self-assembly). Two fatty acid tails (hydrophobic). Glycerol-Phosphate head (hydrophilic). Glycerol and phosphate (hydrophilic). Fatty acids (hydrophobic). Phospholipid arrangement in water.

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BACTERIAL MORPHOLOGY CON’T Plasma (cytoplasmic) membrane

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  1. BACTERIAL MORPHOLOGY CON’T Plasma (cytoplasmic) membrane

  2. Phospholipid bilayer (Self-assembly) • Two fatty acid tails • (hydrophobic) • Glycerol-Phosphate head • (hydrophilic)

  3. Glycerol and phosphate (hydrophilic) Fatty acids (hydrophobic)

  4. Phospholipid arrangement in water

  5. Phospholipid self-arrangement

  6. Proteins • Integral proteins • Transport • Peripheral proteins • Enzymes

  7. Peripheral protein Integral protein

  8. Plasma membrane functions (BET) • Barrier • Energy production • Transport

  9. Plasma membrane • Target for chemotherapy and disinfection • Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents. • Disruption of phospholipids • Selective permeability allows passage of some molecules • Enzymes for ATP production • Photosynthetic pigments on foldings called chromatophores or thylakoids

  10. Transport across membranes • Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration (often known as passive transport) • Facilitative diffusion: Solute combines with a transporter protein in the membrane

  11. Transport across membranes • Active (requires energy, usually from lower to higher concentration)

  12. Passive transport across membranes • Simple diffusion • Facilitated diffusion (permeases) • Osmosis

  13. Higher concentration Lower concentration Facilitated diffusion No energy used !!

  14. Sugar or salt molecules (solute) Osmosis • Liquids flow towards higher solute • concentration (lower liquid concentration) Semi-permeable membrane (only water flows)

  15. Active transport across membranes • Group translocation • Substance is altered during transport (metabolism-glucose-6-PO3) sugars are phosphorylated • Carrier proteins • Similar to facilitated diffusion, but needs energy • Group translocation of substances requires a transporter protein and PEP (phosphoenolpyruvate) • Active transport of substances requires a transporter protein and ATP

  16. Phosphate Group translocation Glucose Lower concentration Higher concentration Energy is used!

  17. phosphoenolpyruvate

  18. Microbial Nutrition Acquisition

  19. Cytoplasm contents • Water, proteins, carbohydrates, lipids, inorganic ions, DNA, RNA and inclusions

  20. Nuclear area • No nuclear membrane • Chromosome • Plasmid

  21. Bacterial chromosome • One only • double stranded (ds) DNA • Attached to plasma membrane

  22. Bacterial plasmid • Extrachromosomal genetic material • Replicate independently • Not crucial for survival (resistance, enzymes, etc)

  23. Ribosomes • Protein synthesis • Two subunits 30 and 50 S = 70 S (rRNA) • Target for antibiotic action

  24. Inclusions • Reserve deposits • lipids, sulfur, carboxysomes • Metachromatic granules • Polysaccharide granules • Gas

  25. Inclusions

  26. Endospores • Only Gram-positives • Bacillus spp. • Clostridium spp. • Highly resistant • Spore coat has a form of dipicolinic acid and Ca+ ions in it

  27. Spores

  28. The eucaryotic cell • Algae • Protozoa • Plants • Animals

  29. The eucaryotic cell (cont.) • Larger and more complex than procaryotes • 10 to 100 mm • Membrane-bounded organelles

  30. Flagella and Cilia • Locomotion • Flagella, few and long • Cilia, numerous and short

  31. Movement of eukaryotic flagella and cilia • Respiratory system • Digestive system • Locomotion

  32. Cell wall of eucaryotes • Not present in all eucaryotes (alga, plants, some fungi) • No peptidoglycan • Simpler than procaryotes

  33. Cell wall of eucaryotes (cont.) • Cellulose • Glucose polymer • Chitin (most fungi, some protozoans) • N-acetylglucosamine polymer

  34. Cell wall of eucaryotes (cont.) • Polysaccharides (yeast) • Glucan • Mannan

  35. Glycocalyx functions • Strengthens the cell surface • Helps attach cells together • Cell to cell recognition • Sticky carbohydrates

  36. Eucaryotes plasma (cytoplasmic) membrane • Similar to procaryotes • Receptor sites (carbohydrates) cell to cell recognition

  37. Eucaryotes plasma (cytoplasmic) membrane (cont.) • Attachment sites for bacteria • Sterols (rigidity) • transport (passive and active)

  38. Eucaryotes passive transport • Diffusion • Facilitated diffusion • Osmosis

  39. Eucaryotes active transport (endocytosis) • Phagocytosis (macrophages –cells are “eating”) • Pinocytosis (extracellular fluid into the cell—cells are “drinking”)

  40. Cytoplasm • Cytoskeleton • Microfilaments • Intermediate filaments • Microtubules

  41. Cytoplasm (cont.) • Cytoskeleton functions • Shape • Movement • Entire cell • Substances within the cell

  42. Nucleus • Spherical to oval • Contains DNA • combined with histones • and nonhistones

  43. Nucleus (cont.) • Chromatin (threadlike) • Non-reproducing cells • Chromosomes (rodlike structure) • Reproducing cells

  44. Endoplasmic reticulum (ER) • Network of sacs • Synthesis and storage of lipids and proteins

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