Transcript Bacteria
Bacteria 4D identify and describe the role of bacteria in maintaining health such as in digestion and causing diseases such as in streptococcus infections and diphtheria. Bacteria Fun Facts! • 99% of all bacteria are helpful!! Bacteria Fun Facts! • One healthy bacterium could reproduce into a colony of more than 2 million in just 7 hours!! Bacteria Fun Facts! • There are more bacteria on your body than there are humans on the entire planet!! Three Domains to categorize all living organisms Six Kingdoms • Eubacteria • Archaebacteria • Protista • Fungi • Plantae • Animalia Two Kingdoms of Bacteria: Archaebacteria Eubacteria Common Characteristics: All Prokaryotes Lack nucleus Single cell Cell walls ARCHAEBACTERIA • Live in extremely harsh environments, like thick mud, extremely salty environments, hot springs • Lack cell wall made of peptidoglycan • DNA sequences similar to eukaryotes • May be ancestors of eukaryotes (us) Places ARCHAEBACTERIA live Deep Sea Vents Hot Springs EUBACTERIA • Live almost everywhere, fresh water, salt water, land, within the human body • Larger of the 2 kingdoms • Surrounded by cell walls containing peptidoglycan Bacteria—What Are They? Bacteria—What Are They? Overview Are Prokaryotic cells No organized nucleus Few cell parts Contain a single circular chromosome Structure of Bacteria • Flagella – whip-like structure used for movement • Pili – short hair-like projections used for movement • Ribosomes – protein synthesis • Peptidoglycan – lipid layer inside cell wall. Cell wall Peptidoglycan Flagellum Cell membrane DNA Ribosome Pili Bacterial Morphology Endospores • Endospores are the most resistant living structures known. • formed by some bacteria to resist drying out, boiling, heat, freezing, radiation, and chemicals. • Can survive several hours boiling & may remain viable for years • Remains dormant until conditions are favorable again then resumes growth and reproduction. • Exposure to proper stimuli (food, warmth & moisture) the spore germinates and a new vegetative cell emerges. • Endospores can survive for thousands of years! What Do They Look Like? Appearance It is single celled. With three basic shapes: • Bacillus – Rod Shaped • Coccus – Round/Sphere • Spirilus – Spiral Shape Cocci: Diplococcus Streptococcus Staphylococcus Neisseria gonorrhoeae Streptococcus pyogenes Streptococcus pneumoniae Shape Bacilla: (Rod Shaped) Diplobacillus Streptobacillus Shape Spirilla: Spiral or corkscrew shaped Role of Bacteria in Symbiotic Relationships Importance of Bacteria Not all bacteria are bad!! • Bacteria are vital to maintaining the living world because: – Some are producers – put oxygen into the atmosphere – Some are decomposers – break down dead organic matter – Some have human uses; E. coli. lives in the human intestines and produces vitamins the body cannot produceUsed to make yogurt and other dairy products – Nitrogen fixation – bacteria live in symbiotic relationship with legumes (bean plants) to convert nitrogen gas to a usable form of nitrogen for plants. Beneficial Bacteria • Protein source • Wine • • • • Oil Eating bacteria Bacterial Cement Sewage Plants Agriculture – Nitrogen fixing bacti Beneficial roles of Bacteria • Chemosynthetic Autotroph Use chemicals to make energy (inorganic compounds) Beneficial roles of Bacteria • Bacteria can also be helpful in the large intestine by preventing infections and producing substances we need, such as vitamin B and K. Beneficial roles of Bacteria Bacteria in the stomachs of cows and sheep are what enable them to digest grass. Bacteria are also essential to the production of yogurt, cheese, and pickles. Beneficial roles of Bacteria Bacteria are necessary to decompose dead plants and animals to recycle. • Saprophytes – Decomposing dead organisms Genetic Engineering Bacteria have been genetically altered to produce insulin Bacteria have been genetically altered to break down oil and other pollutants METABOLISM • Difference between autotroph and heterotroph? • Difference between aerobic and anaerobic? Some Cause Diseases Tetanus Whooping Cough Typhoid Fever Paratyphoid Fever Cholera Plague Tuberculosis Meningitis Clostridium tetani Bordetella pertussis Salmonella typhi Salmonella paratyphi Vibrio cholorae Yersinia pestis Mycobacterium tuberculosis Neisseria meningitidis https://www.youtube.com/wat ch?v=znnp-Ivj2ek Common Bacterial Diseases • Strep-throat • Tooth Decay • Chlamydia • Lyme Disease • Tuberculosis • Cellulitis • Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body. • Most often, it causes mild infections on the skin, causing sores or boils How to control bacteria… • Sterilization – heat, boiling water, hand washing • Disinfectants – Example – lysol • Food storage and processing – canning, keeping food cold or frozen • Vaccines – many bacteria have vaccines to prevent them Preventing Invasions • First line of defense against disease microbes is your body surface (Skin & linings of tubes that lead to exterior) • In addition, epithelial tissues secrete materials that kill microbes on the body surface – Salts in sweat and tears draw H2Oout of microbes, shrinking & killing the ones that live on your skin and in your eyes – Acids in stomach & vagina burn microbes Preventing Invasions – Enzyme (lysozyme) in sweat, tears, saliva, earwax & nasal secretions ruptures bacteria by digesting cell walls – Mucus & cilia trap microbes & push them to the exterior If microbes have penetrated the body….. Three lines of defense – Macrophages within vessels, searching and devouring microbes – Inflammatory response within the lymph nodes – Fever – elevated body temp. helps fight microbes by enhancing the effect of interferons, accelerating the reproduction of T cells & removing minerals from the body so that bacteria cannot use them as nutrients Along with antibodies, you have Complement Proteins • It is a bundle of proteins that travels within the blood stream at all times. • Some enzymes from complement kill the microbe by digesting a hole in its outer membrane. • Others guide macrophages and assist in other ways. Treatments for Bacteria • Once a harmful bacteria has infected the body, antibiotics can be used to attack and destroy the bacteria 400 degree-waterspewing vents located along the Mid-Ocean Ridge Who lives here: Photoautotrophs or Chemoautotrophs? How do they Reproduce? Bacterial Reproduction • Asexual – Binary Fission • Sexual – Conjugation – Transformation – Transduction Bacterial Reproduction Asexual Reproduction Sometime prokaryotes divide by Binary Fission (Asexual Reproduction). • Binary Fission results in 2 identical bacteria through normal cell division. – The DNA molecule replicates itself and the DNA molecules become attached, side by side, to the inner surface of the plasma membrane. – The membrane elongates separating the 2 molecules. Binary Fission Cell reproduction by “splitting” in to two new cells. Reproduction Binary Fission: http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf: :500::500::/sites/dl/free/0073375225/594358/BinaryFission.swf::Bin aryFission https://www.youtube.com/watch?v=7sZ5Nz8_cfc Bacterial Reproduction Sexual Reproduction (DNA Variability) Many times, bacteria can exchange genetic material before dividing by Binary Fission. Because two different bacteria unite to exchange genetic information, it is said to be Sexual Reproduction. • Sexual Reprod. Types (DNA Variability) – Conjugation – Transformation – Transduction Bacterial Reproduction DNA Variability Conjugation (Direct cell to cell contact) Sex Pilus – F Factor codes for the sex pilus • Cells lacking F Factor can only receive DNA during conjugation and is called F• Cells possessing F+ Factor have a sex pilus & can donate DNA – F+ cell contacts the F- cell using its sex pilus & a conjugation bridge is formed – A copy of its DNA is transferred from the F+ to the F- cell. (F- eventually being changed into F+) Conjugation Exchanging genetic material between bacterial cell through a pilus Bacterial Morphology Pilus (Pili) • Short slender tubes formed of protein subunits that extend from the cell wall – Other pili – help bacteria adhere to objects like O2 and food – Sex pilus – involved in conjugation Conjugation Cont. – The conjugation bridge (F+ to F-)can be used to transfer either a plasmid or a portion of the bacterial chromosome. • A plasmid is an extra chromosomal circular DNA segment that can reproduce independently of the bacterial chromosome. Conjugation: http://www.learner.org/channel/courses/biology/archive/animatio ns/hires/a_infect1_h.html Bacterial Reproduction DNA Variability • Transformation – When a bacterium dies, fragments of its DNA may be released intact – If this fragment contacts a competent member, it can be bound to the cell and taken inside (not all bacteria can do this) – After it’s been taken up, part of it is incorporated into the genome (DNA) of the recipient Bacterial Reproduction DNA Variability • Transduction (Virus-mediated transfer) – Transfer of genetic material from one bacterium to another by a virus Bacteria Respiration • Depending on where they are found, bacteria use different types of respiration: • Obligate Aerobes – require a constant supply of oxygen in order to survive. • Obligate Anaerobes – must live in the absence of oxygen. • Facultative Anaerobes – can live with or without oxygen. Questions 1. Which organism lives in the human intestine and aids in the digestive process? A. B. C. D. The bacterium Escherichia coli The fungus Trichophyton rubrum The protozoan Entamoeba coli The algae Fucus vesiculosus 2. Some antibiotics cause patients to exhibit digestive side effects. These side effects are most often the result of — A. bacteria being killed in the digestive tract B. the antibiotics being converted into stomach acids C. too much water being drawn into the digestive tract D. the stomach wall being torn 3. Many species of bacteria can be found in the human mouth. Which of these explains the great variety of bacteria in the mouth? A. Large volumes of air cause bacteria to change form. B. Salivary glands cause mutations in bacterial populations. C. The presence of nutrients makes the mouth a favorable habitat. D. Calcium in the teeth provides a suitable pH environment. 4. Bacteria are present in the digestive tract of some herbivores. The bacteria break down plant cellulose, making it possible for the herbivore to digest plant material. These bacteria live in a stable environment with sufficient food and water. The herbivore and the bacteria in this relationship — A. B. C. D. benefit each other compete for survival are producers are secondary consumers 5. How does using killed or weakened bacteria in an immunization help the body prevent infections? A. B. C. D. Antibodies are formed that fight those types of bacteria. The body develops a fever that kills beneficial bacteria. Bacterial reproductive cycles are disrupted. Bacteria-fighting viruses are activated. 6. Which of the following is found in both cells and viruses? A. B. C. D. Silica Genetic material Digestive cavity Flagella 7. Which of the following is found in both cells and viruses? A. B. C. D. Silica Genetic material Digestive cavity Flagella 8. People infected with the human immunodeficiency virus (HIV) have an increased risk of dying from secondary infections. Which of these best explains how HIV increases the danger of secondary infections? A. B. C. D. HIV produces antigens that damage red blood cells. HIV adds genetic material from harmful microbes. HIV destroys helper T cells. HIV consumes beneficial microbes in the body. 9. People infected with the human immunodeficiency virus (HIV) have an increased risk of dying from secondary infections. Which of these best explains how HIV increases the danger of secondary infections? A. B. C. D. HIV produces antigens that damage red blood cells. HIV adds genetic material from harmful microbes. HIV destroys helper T cells. HIV consumes beneficial microbes in the body. Viruses vs Bacteria Virus Bacteria Not a cell; smaller than a cell Dormant outside a cell Single Cell; oldest form of life; no nucleus Requires a host cell to reproduce for them Reproduce through cell division Cannot take in food Large size Cannot expel waste Found in many environments; soil, water, air, bodies of other organisms, with or without oxygen Consists of two parts: outer coat of protein and hereditary material-DNA or RNA Cytoplasm contains hereditary material; DNA in circular structure called plasmic Diseases: HIV, AIDS, Flu, Smallpox, Warts Diseases: Strepthroat, Anthrax, Diphtheria, MRSA Virus Versus Bacteria