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Transcript
Bacteria: Classification and Structure What are the 6 Kingdoms? Archaebacteria Eubacteria Protists Fungi Plants Animals We are looking at the first two Archaebacteria : Extremists. Larger of the two kingdoms. Contain a variety of organisms Eubacteria: Archaebacteria Live in extreme locations: Oxygen-free environments Concentrated Hot, salt-water acidic water EUBACTERIA Bacteria – all are prokaryotic meaning they do not have a nucleus. Bacteria are unicellullar cells (one cell only) They are found almost everywhere: -water -air -soil -food -skin -inside the body -on most objects Clean skin has about 20 million bacteria per square inch The tip of a needle The red and yellow dots are bacteria Structure of Bacteria Two parts to Bacteria Structure: Arrangement Shape 3 Shapes of Bacteria Bacteria are classified by shape into 3 groups: Spiral: spirilla rod-shaped: bacilli, bacillus Round: cocci 7 Major parts of a Bacteria Cell •Capsule •Cell wall •Ribosomes •Nucleoid •Flagella •Pilli •Cytoplasm CAPSULE Capsule keeps the cell from drying out and helps it stick to food or other cells CELL WALL Cell wall Thick outer covering that maintains the overall shape of the bacterial cell Cell Wall – determined by Gram Staining. Gram positive – stain purple because they have peptidoglycan in their cell wall. Thicker cell wall, but less pathogenic. Gram negative – stain red because they lack peptidoglycan in their cell wall. Thinner cell wall, but generally more pathogenic . Penicillin kills bacteria by making holes in their cell walls. Unfortunately, many bacteria have developed resistance to this antibiotic. RIBOSOMES Ribosomes cell part where proteins are made Ribosomes give the cytoplasm of bacteria a granular appearance in electron micrographs NUCLEOID Nucleoid a ring made up of DNA PILLI Pilli hollow hair-like structures made of protein allows bacteria to attach to other cells. Pilli-singular Pillus-plural FLAGELLA Flagella a whip-like tail that some bacteria have for locomotion Classification Movement Non-motile Flagella Gliding – whiplike structure – secrete a slime CYTOPLASM Cytoplasm clear jelly-like material that makes up most of the cell Metabolic Diversity Chemoheterotrophs: - take in organic molecules for energy. Photoheterotrophs: - use sunlight and photosynthesis for energy but must also take in organic molecules for energy. Photoautotrphs:- Use sunlight energy and photosynthesis to make their own food. chemoautotrophs: - use carbondioxide to make energy but do not require light. Energy Release Oblique aerobes: require oxygen for life. oblique anaerobes: must live in the absence of oxygen. Example: Clostridium botulinum Facultative anaerobes: Can live with or without oxygen. Example: Escherichia coli Example: Mycobacterium tuberculosis Reproduction of Bacteria •Binary Fission- the process of one organism dividing into two organisms •Fission is a type of asexual reproduction •Asexual reproduction- reproduction of a living thing from only one parent How?... The one main (circular) chromosome makes a copy of itself Then it divides into two Reproduction of Bacteria BINARY FISSION Bacteria dividing Completed Reproduction of Bacteria •The time of reproduction depends on how desirable the conditions are •Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions •Some can reproduce every 20 minutes (one bacteria could be an ancestor to one million bacteria in six hours) Bacterial Cell & Nucleiod DNA Ring DNA replication Cell wall synthesis Cell separation Spore formation Endospore•a thick celled structure that forms inside the cell •they are the major cause of food poisoning •allows the bacteria to survive for many years •they can withstand boiling, freezing, and extremely dry conditions •it encloses all the nuclear materials and some cytoplasm Bacteria Survival Bacillus subtilis Endospore-the black section in the middle highly resistant structures can withstand radiation, UV light, and boiling at 120oC for 15 minutes. Bacteria Survival – Nutrition parasites – bacteria that feed on living things saprophytes – use dead materials for food (exclusively) decomposers – get food from breaking down dead matter into simple chemicals important- because they send minerals and other materials back into the soil so other organisms can use them Harmful Bacteria • some bacteria cause diseases •Animals can pass diseases to humans Communicable Disease – Disease passed from one organism to another This can happen in several ways: •Air •Touching clothing, food, silverware, or toothbrush •Drinking water that contains bacteria Harmful Bacteria Human tooth with accumulation of bacterial plaque (smooth areas) and calcified tartar (rough areas) Helpful Bacteria (Importance of bacteria) •Decomposers help recycle nutrients into the soil for other organisms to grow •Bacteria grow in the stomach of a cow to break down grass and hay (cellulose) •Most are used to make antibiotics •Some bacteria help make insulin •Used to make industrial chemicals Helpful Bacteria E.coli on small intestines Helpful Bacteria •Used to treat sewage Organic waste is consumed by the bacteria, used as nutrients by the bacteria, and is no longer present to produce odors, sludge, pollution, or unsightly mess. •Foods like yogurt, cottage & Swiss cheese, sour cream, buttermilk are made from bacteria that grows in milk Controlling Bacteria 3 ways to control bacteria: 1) Canning- the process of sealing food in airtight cans or jars after killing bacteria •endospores are killed during this process 2) Pasteurization- process of heating milk to kill harmful bacteria 3) Dehydration- removing water from food •Bacteria can’t grow when H2O is removed •example: uncooked noodles & cold cereal Controlling Bacteria Antiseptic vs. Disinfectants Antiseptic- chemicals that kill bacteria on living things •means – “against infection” Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things Summary on the structure of bacteria Structure Function Cell Wall Protects and gives shape Outer Membrane Protects against antibodies (Gram Neg. Only) Cell Membrane Regulates movement of materials, contains enzymes important to cellular respiration Cytoplasm Contains DNA, ribosomes, essential compounds Chromosome Carries genetic information Plasmid Contains some genes obtained through recomb. Capsule & Slime Layer Protects the cell and assist in attaching cell to other surfaces Endospore Protects cell agains harsh enviornments Pilus Assists the cell in attaching to other surfaces Flagellum Moves the cell 37 Bacteria and Diseases. Some bacteria cause diseases --Disease causing bacteria are called PATHOGENS. Disease Bacteria and Disease Pathogen Areas Mode of Botulism affected transmission Clostridium botulinum Nerves Improperly preserved food Cholera Vibrio cholerae Intestine Contaminated water Dental Caries Streptococcus mutans, sanguis, salivarius Teeth Environment to mouth Gonorrhea Neisseria gonorrhoeae Urethra, fallopian Sexual contact Lyme disease Berrelia burgdorferi Skin, joints Tick bite Rocky Mountain SF Rickettsia recketsii Blood, skin Tick bite Salmonella Salmonella Intestine Contaminated food, water Strep throat Streptococcus pyogenes URT, blood, skin Sneezes, coughs, etc. Tetanus Costridium tetani Nerves Contaminated wounds Tuberculosis Mycobacterium tuberculosis Lung, bones coughs Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. DENTAL CARIES CHOLERA ROCKY MOUNTAIN SF LYME DISEASE SALMONELLA STREP THROAT TETANUS TUBERCULOSIS Plants, Fungi & Animal Cells Plants Only Cell wall of cellulose Central vacuole Chloroplasts Animals Only Lysosomes Centrioles Fungi Only – Cell wall of chitin – Central vacuole – No chloroplasts