1 / 24

Introduction to Prokaryotes and Eukaryotes

Introduction to Prokaryotes and Eukaryotes. Chapter 6, 27. Three Domains of Life. Archaea Bacteria Eukarya. Three Domains of Life. There are 2 main categories of cells: Prokaryotes – Bacteria Eukaryotes – Plants, Fungi, Protists , Animals . Early life: First cells . 3.5-2.0 BYA

yen
Download Presentation

Introduction to Prokaryotes and Eukaryotes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Introduction to Prokaryotes and Eukaryotes Chapter 6, 27

  2. Three Domains of Life • Archaea • Bacteria • Eukarya

  3. Three Domains of Life • There are 2 main categories of cells: • Prokaryotes – Bacteria • Eukaryotes – Plants, Fungi, Protists, Animals

  4. Early life: First cells • 3.5-2.0 BYA • First cells were simple • Branched into two major lines: bacteria and archaea Samples of Archeans from an ocean vent

  5. Bacterial Phylogeny Ancient bacteria • Note the presence of a common ancestor • Split off into two domains: archaea and bacteria

  6. Archaea • Diverse group of primitive bacteria • AKA “extremophiles” • Methanogens • Halophiles • Thermophiles

  7. Eubacteria, or Bacteria • Very diverse group of bacteria • More helpful than harmful • Categorized by: • Shape • Arrangement • Cell wall composition • Metabolic requirements

  8. Bacterial Structure

  9. Bacterial Shapes • Cocci: round • Bacilli: rod-shaped • Spirochete: spiral-shaped

  10. Cell Wall • Eubacteria possess a cell wall in addition to their membrane • This cell wall is composed of sugars and proteins: peptidoglycans • Hans Gram (1884) developed differential stain to distinguish one type from another: Gram stain

  11. Metabolic requirements • Obligate aerobes – require oxygen for cellular respiration • Obligate anaerobes – cannot live in the presence of oxygen • Facultative anaerobes – can live with or without oxygen

  12. Metabolism of Microbes: Autotrophs Photoautotroph: uses light energy to generate organic compounds from CO2 cyanobacteria Chemoautotroph: uses energy from inorganic chemicals and CO2 to produce organic compounds Sulfolobus

  13. Photoheterotroph: uses light energy but obtains organic compounds from other organisms Rhodobacter Chemoheterotroph: organism that uses organic chemicals obtained from other organisms for energy Example: E. coli Metabolism of Microbes: Heterotrophs

  14. Role of Bacteria in the Environment • Photoautotrophs generate O2 in the atmosphere • Symbiotic relationships • Bacteria also fix nitrogen so that plants can use it: nitrogen fixation • Conversion of nitrogen gas to ammonia • Bacteria are decomposers of dead material

  15. Role of Bacteria to Humans • Used in research and biotechnology applications • Many bacteria are used in food production: • Sauerkraut • Cheese • Yogurt • Many bacteria are agents of disease • Necrotizing fasciitis (“flesh eating” disease)

  16. Cellular Theory All living things are composed of cell All cells come from pre-existing cells Cells are the basic unit of structure and function in living things

  17. Organelles • A specialized structure that performs a certain function within a cell • Number and complexity depends on cell type

  18. All Cells Have… • Plasma membrane • Boundary of cell • Controls what enters, leaves • Role in communication

  19. All Cells Have… • Cytoplasm/Cytosol • Semi-fluid substance • Where organelles are found

  20. All Cells Have… • Chromosomes • Genetic material (DNA)

  21. All Cells Have… • Ribosomes • Site where protein is made

  22. Prokaryotes: Small in size (range: 2-20m) Genome is singular chromosome not organized around proteins Do not have membrane-bound organelles Flagella do not have 9+2 arrangement Ribosomes 70s Eukaryotes: Large size (to 100m) Genome organized around proteins; multiple chromosomes present Flagella found in 9+2 arrangement Contain membrane-bound organelles Ribosomes 80s Prokaryotes vs. Eukaryotes

More Related