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KINGDOM MONERA. 100,000++ spp. Your body-1000 billion animal cells 10,000 billion bacteria cells. Bacterial Cell Structure. STRUCTURE OF BACTERIA. Thousand times bigger than a virus Unicellular [living] Cell is simpler than other living organisms
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100,000++ spp Your body-1000 billion animal cells 10,000 billion bacteria cells M. Paine
Bacterial Cell Structure M. Paine
STRUCTUREOF BACTERIA • Thousand times bigger than a virus • Unicellular [living] • Cell is simpler than other living organisms • Can carry out all the functions of living organisms M. Paine
STRUCTURE OF BACTERIA M. Paine • Rigid cell wall made of polysaccharides and amino acids [protection] • Plasma membrane • Serves as a mitochondrion, endoplasmic reticulum and sometimes a chloroplast • Controls entry and exit of substances
STRUCTURE OF BACTERIA • Prokaryotes • Do not have a true nucleus • No nuclear membrane • DNA is combined with histone ( a protein) as in eukaryotes • Single chromosome consists of a closed loop • Many have a waxy capsule for protection • Especially disease causing bacteria • Some have flagella for locomotion M. Paine
STRUCTURE OF A BACTERIAL CELL Chromosome Pilus (fimbria) Ribosome Storage granule Flagellum Capsule or Slime layer Plasmid Cell Wall Cytoplasm Plasma Membrane M. Paine
SHAPES OF BACTERIA MAKE NOTE • Spherical : cocci • Rod shaped: bacilli • Spiral shaped: spiralla • Comma shaped: vibrios M. Paine
Shapes of Bacteria • Coccus • Chain = Streptoccus • Cluster = Staphylococcus • Bacillus • Chain = Streptobacillus • Coccobacillus • Vibrio = curved • Spirillum • Spirochete • Square • Star M. Paine
A BACTERIAL DISEASE • TUBERCULOSIS M. Paine
CHRONIC BACTERIAL INFECTION • AFFECTS ALL ORGANS OF THE BODY • MAINLY THE LUNGS M. Paine
Mycobacterium tuberculosis • CAUSED BY: • TB bacillus • Covered with a waxy coat • Protection from drying out • Heat • Bodies immune system • Can remain alive for a long time • Can survive in dust particles M. Paine
CHARACTERISTICS • Bacteria are the oldest and most abundant organisms living on the Earth. • Thrive in a variety of environments • Bacteria are mostly useful but can cause diseases • Can only be seen under a microscope • Thousand times bigger than a virus • Occur in diverse shapes and types M. Paine
MORE CHARACTERISTICS • The DNA of bacteria is made of a single chromosome. • In favourable conditions bacteria reproduce asexually by binary fission • In unfavourable conditions (high temperatures, dryness) bacteria form spores with a thick protective coat M. Paine
SIZE OF BACTERIA • Unit for measurement : Micron or micrometer,μm: • 1μm = 10 -3 mm • Size: Varies with kinds of bacteria, and also related to their age and external environment. • Cocci: sphere, 1μm • Bacilli: rods , 0.5-1 μm in width -3 μm in length • Spiral bacteria: 1~3 μm in length and 0.3-0.6 μm in width M. Paine
BINARY FISSION • FAVOURABLE CONDITIONS • Rapid [once every 20 minutes] • Split into two [binary fission] • DNA duplicates itself • Cytoplasm is divided by the cell wall growing inwards • Each of the new cells contains the same genetic information as the parent cell • Ideal conditions = warmth, moisture, food, oxygen, lack of toxins and correct pH M. Paine
Binary Fission M. Paine
Rapid Generation Times 1cell to 2 million cells in 7 hours! Only a build up of waste or depletion of food will stop growth M. Paine
REPRODUCTION UNDER UNFAVOURABLE CONDITIONS • From a thick protective coat around themselves = spore • Bacterium becomes dormant inside the spore • Can withstand unfavourable conditions e.g. dryness, high temperatures • Spore splits open when conditions become better to release the bacterium • Followed by normal rapid binary fission M. Paine
HOW SERIOUS • 1993 world health organisation proclaimed the tuberculosis pandemic was a global emergency • Pandemic = global epidemic with the possibility of all people benig affected • 2002 highest mortality rate was in africa M. Paine
HOW IS TB SPREAD • Spread in moisture droplets • From an infected to an uninfected person • TB bacillis is spread through the air when an infected people cough, sneeze, talk or spit • Uninfected person breathes in the moisture droplets containing the bacillus • Bacilli multiply in their air sacs M. Paine
AFTER INFECTION • STRONG IMMUNE SYSTEM • Infection is contained walled off in a fibrous capsule • Lie dormant for years • No symptoms • WEAK IMMUNE SYSTEM • Bacilli multiply • Individual gets ill with pulmonary TB M. Paine
EFFECTS OF TB [SYMPTOMS] • Individual does not feel well • Persistent cough [coughing up blood] • Weight loss • Fevers • Night sweats • Tired and weak • Patient could lose earnings while ill • Stigma attached to this disease • Untreated it is easily spread M. Paine
MANAGEMENT BY PERSON • TB can be cured • Treated with an aggressive antibiotic regime called DOTS • Directly Observed Therapy, Short Course • Patients are carefully monitored to make sure that they take their full course of antibiotics • Watched as they swallow the tablets! • Lasts for six months • They will not be able to infect others within days of starting treatment M. Paine
MANAGEMENT OF TB BY SOCIETY • PREVENT THE SPREAD OF TB • Screen people at risk • Treat infected patients quickly • Solve overcrowding and malnutrition • SUPPLY GOOD QUALITY INFORMATION • Eg healthy diets + ways to decrease spreading TB • PROVIDE WELL EDUCTAED HEALTH CARE WORKERS • Persuade patients to take drugs • IMMUNISATION AGAINST TB • BCG vaccine given soon after birth M. Paine
PROBLEM:MUTI- DRUG RESISTANT TB • Many patients stop taking the medication once they start feeling better • TB bacillus then develops resistance to the drugs the next time they are ill with TB and on treatment again • Called multi- drug resistant TB M. Paine
PREVENTION • Most children are immunised against TB soon after birth with the BCG vaccine • Repeated once or twice before going to school • Poverty and the underlying social problems of overcrowding and malnutrition need to be addressed: Overcrowding increases the chance of the TB bacillus spreading Malnutrition weakens the immune system M. Paine
RELATIONSHIP BETWEEN HIV AND TB • HIV weakens the immune system • HIV positive people infected with TB are very likely to become sick • TB is the leading cause of death among people who are HIV-positive • IN AFRICA, HIV IS THE MAIN REASON WHY THE INCIDENCE OF TB HAS INCREASED OVER THE LAST 10 YEARS M. Paine
Good Bacteria • Food production (cheeses , yogurt , alcohol , etc) • Making medicines (insulin) • Recycling M. Paine
Bad Bacteria • Are pathogenic (cause disease) • Most are parasitic which cause infections. • Antibiotics are used to treat these infections. An antibiotic is a chemical agent produced by one organism that is harmful to another organism. • One of the most popular antibiotics is Penicillin which comes from a fungus. It destroys the bacteria’s cell wall & therefore causes the cell membrane to break up due to the hypotonic environment. M. Paine
THE END M. Paine
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