Bacteria Presentation Powerpoint (ppt)

Where can we find bacteria?
What are bacteria?
• Unicellular microorganisms
• Different shapes – sphere (coccus), rod (bacillus), spiral
• Don’t have a membrane bound nucleus – genetic
material is typically in a single circular chromosome
What are bacteria?
• Found in every habitat on Earth
• Approximately 10 times as many bacterial
cells as human cells in the human body
• First discovered in 1676 using a microscope
• First antibiotic developed in 1910
What diseases are caused by bacteria?
• Necrotizing faciitis – flesh eating bacteria
– Caused by different types of bacteria
What diseases are caused by bacteria?
• Anthrax
– caused by Bacillus anthracis
– Unusual because it can form long-lived spores
– Has been used as a biological warfare agent and in
What diseases are caused by bacteria?
Food poisoning
Salmonella enterica
• Rod–shaped flagellated bacterium
• Discovered by American scientist named Daniel
• Infects cattle and poultry (chicken and eggs)
• Disease Salmonellosis – included diarrhea, fever,
abdominal cramps
• 40,000 cases reported a year, about 400 people a
year die of Salmonellosis
• Avoid by not eating raw or undercooked meat,
poultry, eggs
Peanut Butter and Salmonella
• Salmonella enterica typhimurium recently
found in peanut butter products that came
from a peanut processing facility
• Hundreds have become sick, possibly 6 died as
a result
E. coli
E. coli
• Commonly found in lower intestines of warmblooded animals
• Most strains are harmless but some cause
food poisoning
• Harmless strains are part of the normal flora
of the gut – they benefit the host by
producing vitamin K or by preventing the
establishment of harmful bacteria
E. coli
• Harmful strains produce toxins that cause illness
• Illness is associated with eating unwashed
vegetables or contaminated meat
• Fecal-oral transmission
• The illness can be fatal
• In 2006, E. coli strain O157:H7 found in spinach
• Prevent illness by washing hands, cooking food
thoroughly, washing veggies, avoid unpasteurized
Is all bacteria bad?
• Who likes cheese? Yogurt?
– Bacteria is used in dairy processing -Lactobacillus
Is all bacteria bad?
• Bacteria to clean up oil spills
– Bacteria feed on the toxin and break it down
– Pseudomonas putida
Is all bacteria bad?
• Nitrogen fixing bacteria – plants
Is all bacteria bad?
• Useful in science – molecular biology,
genetics, biochemistry
• Grow quickly and have simple DNA
• Can insert DNA into them and get many copies
of it – cloning
• Or insert DNA and determine function of a
gene or what effect a mutation has
What are fungi?
• Eukaryotic organisms
• Heterotrophs – get their energy from organic
materials (do not photosynthesize)
• Most are multicellular, some unicellular
• Includes yeasts, molds, mushrooms
Diseases caused by fungi
• Ringworm
• Athelete’s foot
Are all fungi bad?
Fungus Penicillium chrysogenum produces the
antibiotic Penicillin
Practices to avoid bacteria and fungi
• Hand washing
• Cooking food properly
• Washing fruits and vegetables
Practices to avoid bacteria and fungi
• What else?
Photo Credits
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