Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to...
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Transcript of Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to...
![Page 1: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/1.jpg)
Introduction to Bacteria
![Page 2: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/2.jpg)
What are bacteria?• Single celled organisms
• Very small
• Need a microscope to see
• Can be found on most materials and surfaces– Billions on and in your body right now
E. Coli O157:H7 can make you very sick.
Streptococcus can cause strep throat.
This E. coli helps you digest food.
![Page 3: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/3.jpg)
What do they look like?
• Three basic shapes– Rod shaped called bacilli
(buh-sill-eye)– Round shaped called
cocci (cox-eye)– Spiral shaped
• Some exist as single cells, others
cluster together
Bacilli
Spiral
Cocci
Cluster of cocci
![Page 4: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/4.jpg)
Bacteria are ALIVE!
• What does it mean to be alive?
– They reproduce (make more of themselves)
– They need nutrients
![Page 5: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/5.jpg)
Differences between Bacterial and Human Cells
• Bacterial cells– No nucleus– No intracellular
organelles (but
ribosomes)– No junk DNA– Plasmids,
bacteriophage
• Human cells– Nucleus– Intracellular organelles
(ribosomes subtly different)
– Lots of junk DNA– Viruses
![Page 6: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/6.jpg)
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Major Structures of a Bacterial Cell
•Capsule
•Cell wall
•Ribosomes
•Nucleoid
•Flagella
•Pilli
•Cytoplasm
![Page 7: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/7.jpg)
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Capsule
keeps the cell from drying out and helps it stick to food or other cells
![Page 8: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/8.jpg)
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Cell wall
Thick outer covering that maintains the overall shape of the bacterial cell
![Page 9: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/9.jpg)
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Ribosomes
cell part where proteins are made
Ribosomes give the cytoplasm of bacteria a granular appearance in electron micrographs
![Page 10: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/10.jpg)
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Flagella
a whip-like tail that some bacteria have for locomotion
![Page 11: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/11.jpg)
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Pilli
hollow hair-like structures made of protein
allows bacteria to attach to other cells.
Pilli-singular Pillus-plural
![Page 12: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/12.jpg)
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Cytoplasm
clear jelly-like material that makes up most of the cell
![Page 13: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/13.jpg)
The Gram stain procedure
Developed in 1884 by the Danish physician Hans Christian Gram
An important tool in bacterial taxonomy, distinguishing so-called Gram-positive bacteria, which remain coloured after the staining procedure, from Gram-negative bacteria, which do not retain dye and need to be counter-stained.
Can be applied to pure cultures of bacteria or to clinical specimens
Top: Pure culture of E. coli (Gram-negative rods)Bottom: Neisseria gonorrhoeae in a smear of urethral pus(Gram-negative cocci, with pus cells)
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How do bacteria reproduce?
• Grow in number not in size– Humans grow in size from child to adult
• Make copies of themselves by dividing in half– binary fission
– Conjugation (exchange of genetic information using pili)
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How do bacteria eat?• Some make their own food from
sunlight—like plants
• Some are scavengers– Share the environment around them
• Example: The bacteria in your stomach are now eating what you ate for breakfast
• Some are warriors (pathogens)– They attack other living things
• Example: The bacteria on your face can attack skin causing infection and acne
Photosynthetic bacteria
Harmless bacteria on the stomach
lining
E. Coli O157:H7 is a pathogen
![Page 16: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/16.jpg)
What is a pathogen?
• Bacteria that make you sick
– Why do they make you sick?
• To get food they need to survive and reproduce
– How do they make you sick?
• They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destroy body tissue
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Where do you get a pathogen?
• Contact with people who are sick
– Direct or indirect
• Food, Water, or other Surfaces that are contaminated
Indirect contact
Direct contact
Foods that could be
contaminated
![Page 18: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/18.jpg)
A Closer Look – Where do you get a pathogen
Indirect Contact
Direct Contact
Foods and water may be
contaminated
![Page 19: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/19.jpg)
Are all bacteria pathogens?• No, most are harmless
• Some are even helpful– Examples of helpful bacteria:
• Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine
• Leuconostoc: makes pickles & sauerkraut
• Pediococcus: makes pepperoni, salami, & summer sausage
![Page 20: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/20.jpg)
A Closer Look – Helpful Bacteria
Pediococcus - used in production of fermented meats
Leuconostoc cremoris – used in the production of buttermilk and
sour cream
Lactobacillus casei – found in human intestines and mouth to improve digestion
Lactobacillus bulgaricus – used in the production of yogurt
www.bioweb.usu.edu
![Page 21: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/21.jpg)
What are some common pathogens?• Pathogenic E. coli
(like O157:H7)– Found in ground beef, contaminated
fruits and vegetables
• Salmonella– Found in raw meats, poultry, eggs,
sprouts, fruit and vegetables
• Listeria– Found in deli foods, lunch meats,
smoked fish and vegetables
E. coli O157:H7
Salmonella
Listeria
![Page 22: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/22.jpg)
Examples of PathogensSalmonella
Staphylococcus aureus
Campylobacter jejuni
E. coli O157:H7
What shape are these bacteria?
Cocci, bacilli, or spiral?
![Page 23: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/23.jpg)
How can I avoid pathogens?
• Wash your hands often so you won’t transfer bacteria to your mouth or food
– Warm water with soap for 20 seconds, rub hard between fingers and nails
USDA NIFSI Food Safety in the Classroom©University of Tennessee, Knoxville 2006
![Page 24: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/24.jpg)
• Cook food thoroughly to kill any pathogens that may be in your food
• Store food properly to limit pathogen growth
– Cold temperatures (40F)
How can I avoid pathogens?
USDA NIFSI Food Safety in the Classroom©University of Tennessee, Knoxville 2006
![Page 25: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/25.jpg)
Review• Bacteria are living organisms
• Most are harmless
• A few are pathogens that make you sick
• You can reduce the risk of getting sick by washing your hands and handling food properly.
USDA NIFSI Food Safety in the Classroom©University of Tennessee, Knoxville 2006
![Page 26: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/26.jpg)
Stained Bacteria Cells at 4x
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Stained Bacteria Cells at 10x
![Page 28: Introduction to Bacteria. What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces –Billions.](https://reader031.fdocuments.in/reader031/viewer/2022032107/56649ef15503460f94c01be3/html5/thumbnails/28.jpg)
Stained Bacteria Cells at 40x