Kingdom Monera Bacteria Common bacteria Prokaryotes Strep throat Anthrax Chlamydia E. coli Meningitis Salmonella Micrococcus(intestinal) Streptococcus mutans Haemophilusinfluenzae Cellphonious bacterious Unicellular(single celled) organisms No nucleus (do have nucleic acid DNA) No membrane-bound organelles Smaller & less ribosomes Are smaller than the smallest eukaryote 1
Cell Structure & Function is a very small cell with all the structures necessary to carry out its life functions Ribosomes: protein synthesis Cell Wall: Support and protection Prevents cell from bursting Cell membrane: surrounds cell & regulates transport Flagella:whip like protrusion for movement Pili: hair like structures (protein) for sticking to another bacteria during sexual reproduction (conjugation) Capsule: sticky, gelatinous; surrounds cell wall to protect against dessication(drying out) and phagocytosis (some bacteria) Chromosome: single DNA molecule that is not contained within a nucleus; contains most of the bacterium s genes Plasmid(s):small circular chromosome piece that contains a few genes Bacteria Flagella Bacteria Structure First antibiotic: Penicillin (1928 Sir Alexander Fleming) an airborne mold that interferes with the ability of some bacteria to make cell walls 2
Endospores Classification of Bacteria some bacteria can transform into dormant state called an Endospore a way to survive difficult conditions involves formation of a thick wall around itself are able to resist: heat drought radiation - when environment improves, the endospore germinates - to kill endospores, items must be sterilized (i.e. heated under high pressure: pressure cooker or autoclave) Archaebacteria: Harsh environments Cell structures differ from other monerans : true or traditional bacteria Archaebacteria: The Extremists 1. Methanogens Produce methane Live in swamps, guts of cows & humans Used to treat sewage & purify water 2. Thermoacidophiles Heat-and acid-loving Live around deep ocean vents where water temperatures are often above 100 celsius Live in hot, acidic waters of sulfur springs 3. Chemosynthesizers Live in deep sea volcanic vents Use inorganic compounds for energy (H 2 S) 4. Halophiles Live in extremely salty places (eg. Dead Sea or Salt Lake) So-called true bacteria 1. Gram Positive Bacteria Cell wall made of protein and sugar Turn purple after gram staining 2. Gram Negative Bacteria Extra layer of lipid outside of cell wall Turn pink/red after gram staining Require different types of antibiotics to treat infections 3. Cyanobacteria Perform plant-like photosynthesis O 2 is released as bi-product 3
Diversity of Bacteria So-called true bacteria 1. The Heterotrophs Live almost everywhere Use organic molecules as food source Some are parasites Some are saprophytes (feed on dead organisms or organic wastes break down and recycle the nutrients locked in the body tissues of dead organisms 1. Cell Shape 2. Colony Formation 3. Cell Wall Gram Positive or Negative 4. Motility Some don t move Some move by one or more flagella 5. Colony Appearance Colour Shape Shininess 6. Method of Obtaining Energy 7. Cellular Respiration 2. Photoautotrophs Make their own food using photosynthesis Live in places with sunlight Cyanobacteria contain chlorophyll that traps the sun s energy used in photosynthesis 3. Chemoautotrophs Make their own organic molecules for food Obtain energy by breaking down and releasing the energy of inorganic compounds (sulfur and nitrogen) Ex. Nitrogen-fixing bacteria of the nitrogen cycle 4
Identifying Bacteria Identifying Bacteria Gram stain: Technique that distinguishes two groups of bacteria The stain reflects a difference in the bacterial cell walls Cell walls are made of different arrangements of sugars and amino acid molecules React differently to Gram stain Gram positive (+) bacteria are purple Gram negative (-) bacteria are pink Bacteria shape Cocci (spheres) Bacilli (rods) Spirilla(spirals) Growth pattern Diplo(paired arrangement) Staphylo(grape arrangement) Strepto(chain of cells) Strepto-Coccus Strepto-Bacillus 5
Spirillum Reproduction 1. Binary Fission (asexual reproduction) Method of reproduction for most bacteria Occurs under normal conditions Process: 1. DNA replicates (ie. doubles) 2. Cell divides 3. Result: 2 identical daughter cells 2. Conjugation (sexual reproduction) DNA is exchanged between bacteria cells Cell to cell contact using pili Increases diversity 3. Transformation (sexual) Bacteria cells that pick up DNA from dead bacteria cells 4. Transduction (sexual) Use of viruses to transfer DNA between bacteria cells Bacteria Reproduction 2. Sexual by conjugation Cell-to-cell contact One bacterium transfers all or part of its chromosome to another cell through or on a bridge-like structure called a pillusthat connects the two cells Results in a bacteria with a new genetic composition The bacterium then undergoes binary fission to produce more cells with the same genetic makeup 6
Bacteria Reproduction Practical uses for Bacteria 3. Sexual by Transformation The process by which bacterial cells pick up and incorporate DNA from dead bacterial cells of the same or a closely related species 4. Sexual by Transduction Using a virus (bacteriophage) to transfer DNA from one bacterial cell to another Bacteria is both beneficial and essential for humans E. coli, which is present in the colon, metabolizes fecal material and allows animals to absorb the minerals and Vitamin K that is produced. Used in food production (cheese, yogurt) Decomposers(recycling of nutrients, supplying O2) Nitrogen fixing bacteria in plants(used for growth) Antibiotic production Practical Uses for Bacteria Bacteria are also used in the process of producing recombinant DNA DNA from another source is placed into the bacterial DNA This creating a new useful strain Utilizes bacteria to mass-produce proteins of specific interest like: hormones insulin blood clotting factor 6. Cellular Respiration Process by which nutrients are broken down to provide energy A. Obligate aerobes Need oxygen to live (eg. Tuberculosis) B. Obligate anaerobes Killed by oxygen (eg. Clostridium tetani in deep wounds) C. Facultative anaerobes Can use oxygen if it is available (eg. E. coli in human intestines) 7