1. Chapter 28 Kingdom Monera Prokaryotes

2. 28.1 Prokaryotic Diversity Prokaryotes vs Eukaryotes 1.Prokaryotes are single-celled In some types, individual cells adhere to each other within a matrix and form filaments; however the cells retain their individuality. 2. Cell Size- most prokaryotic cells are only 1μm or less in diameter 3. Chromosomes- naked circular DNA is localized in a zone of the cytoplasm called the nucleoid region. 4. Cell division & genetic recombination- bacteria reproduce by binary fission. 5. Internal compartmentalization- bacteria have no compartments, cytoskeleton or organelles (except ribosomes). 6. Flagella- single fiber of the protein flagellin. 7. Metabolic diversity- anaerobic and aerobic; photosynthesize; chemoautotrophic.

3. 28.1 cont’d Archaebacteria vs Eubacteria 1.Cell Wall Eubacteria- have cells walls of peptidoglycan (carbo-protein complex) Archaebacteria- cell walls lack peptidoglycan 2. Plasma membranes- membranes have different types of lipids 3. Gene expression- ribosomal proteins and RNA polymerase are distinctly different. 4. DNA replication- although both have a single replication origin, the nature of this origin and the proteins that act there are quite different.

4. 28.2 Prokaryotic Cell Structure Bacteria are the oldest, structurally simplest and most abundant forms of life on Earth. 1. Forms (three types) a. Bacillus- straight and rod-shaped b. Coccus- spherical-shaped c. Spirillus- long and helical-shaped

5. 28.2 cont’d 2.Cell Wall- maintains the shape of cell and protects it from swelling and rupturing. Consists of peptidoglycan (network of polysaccharide molecules connected by polypeptide cross links) Thick layers result in a Gram (+) test Stains purple Thin layer results in a Gram (-) test Stains red More common types of Gram (-) are resistant to antibiotics

6. 28.2 3.Flagella & Pili- whip-like tail used for movement; hair-like structures that occur on the surface of some bacteria. Help bacteria attach to appropriate substrate and exchange genetic info. 4.Capsule- additional gelatinous layer surrounding other wall layers; enables prokaryotes to adhere to surfaces and other cells. 5. Endospores- thick wall around chromosomes and small portion of cytoplasm. Formed in nutrient poor conditions; adaptation

7. 28.2 The Cell Interior 1.Internal membranes- folded regions of plasma membrane (function in respiration or photosynthesis). 2.Nucleoid region- double stranded ring of DNA. 3.Ribosomes- smaller than those of eukaryotes; differ in protein & RNA content. Important because antibiotics, like tetracycline, can tell the difference –they bind to bacterial ribosomes & block protein synthesis.

8. 28.3 Prokaryotic Genetics Prokaryotes do not reproduce sexually, but can exchange DNA between different bacterial cells (conjugation); from viruses (transduction); directly from the environment (transformation); or mutation. 1. Conjugation requires plasmids. These are fragments of extra chromosomal DNA that replicate independently of the main chromosome. Plasmids may encode functions that can confer an advantage for the cell, like antibiotic resistance, but are not required for normal function. The best known plasmid is the F plasmid. Bacterial Conjugation 2. Transduction- the movement of a few specialized genes or any gene (general) using a bacteriophage. Animation Quiz 2- Transduction (Generalized)

9. 28.3 cont’d 3. Transformation- process by which one bacteria dies and ruptures, spilling its fragmented DNA into surrounding environment. This DNA can be taken up by another cell and incorporated into its genome, thereby transforming it. 4. Mutation- change within the DNA either spontaneously, or because of damage due to radiation, UV light or chemicals. Causes concern because of strains like MRSA (methicillin-resistant Staphylococcus aureus). These strains appear to have arisen rapidly and are difficult to treat.

10. 28.4 Prokaryotic Metabolism Autotrophs- organisms that obtain their carbon from inorganic CO 2 1.Photoautotrophs- use energy of sunlight to build organic molecules from CO 2 2.Chemoautotrophs- bacteria that obtain energy by oxidizing inorganic substances. Heterotrphs- organisms that obtain at least some of their carbon from organic molecules like glucose. 1.Photoheterotrophs- use light as a source of energy, but obtain carbon from carbohydrates and alcohols produced by other organisms. 2.Chemoheterotrophs- decomposers and pathogens; obtain energy and carbon from organic molecules. Infection Bacteria secrete proteins that act on functions of normal eukaryotic cells. Ex: Yersinia-inject protein into macrophages; disrupts signals that tell macrophages to engulf bacteria.

11. 28.5 Bacterial Diseases 1.Cholera5. Whooping cough9. Rheumatic fever 13. Anthrax 2.Leprosy6. Diptheria10. Tuberculosis * 14. Botulism 3.Tetanus7. Lyme disease11. Typhoid 4.Pneumonia8. Scarlet fever12. Dysentary Tuberculosis- still a leading cause of death in humans; 1/3 of all people worldwide are infected. Afflicts the respiratory system and is easily transmitted through the air. Dental caries- tooth decay-due to bacteria present in plaque. STD’s 1.Gonorrhea- Neisseria gonorrhoeae 2.Syphilis- Treponema pallidum 3.Chlamydia- Chlamydia trachomatis (“silent” STD) **** Bacterial infections are treated with ANTIBIOTICS ****

12. 28.6 Beneficial Prokaryotes Importance of Bacteria 1.Decomposition- prokaryotes carry out the decomposition portion of several chemical cycles (carbon, nitrogen, phosphorus, sulfur) 2.Fixation- help return elements from inorganic forms to organic forms that heterotrophs can use. (carbon, nitrogen) 3.Symbiosis- ecological relationship between different species that live in direct contact with one another. (mutualism, commensalism, parasitism) 4.Used in production of vinegar, cheeses, milk, yogurt and bread 5.Used in removing environmental pollutants (bioremediation) ex: oil eating bacteria 4. Used in genetic engineering Ex: Bacillus thuringenesis- being used for insect control in plants