Bacteria Introduction to the Bacteria Bacteria are prokaryotic
Bacteria
Introduction to the Bacteria • Bacteria are prokaryotic and unicellular. • Bacteria have cell walls. • Bacteria have circular DNA called plasmids. • Bacteria can be anaerobes or aerobes. • Bacteria are heterotrophs or autotrophs.
3 Shapes of Bacteria • Bacteria are classified by shape into 3 groups: Spiral: spirilla rod-shaped: bacilli, bacillus Round: cocci
Bacteria are Named by Shape • Cocci (ball-shaped). – Streptococcus mutans. • Bacillus (rod-shaped). – Clostridium botulinum. • Spirilli (spiral-shaped). – Treponema palladium.
Shapes of Bacteria
7 Major Structures of a Bacteria Cell • Capsule. • Cell wall. • Ribosomes. • Nucleoid. • Flagella. • Pilli. • Cytoplasm.
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.
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).
Bacteria Survival • • • 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. vhighly resistant structures. vcan withstand radiation, UV light, and boiling at 120 o. C for 15 minutes.
Bacteria Survival – Food sources • 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. üimportant- because they send minerals and other materials back into the soil so other organisms can use them.
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 H 2 O is removed.
Controlling Bacteria Antiseptic. 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.
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 and calcified tartar.
Helpful 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. • 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 ü Organic waste is consumed by the bacteria, used as nutrients by the bacteria, and is no longer present to produce odors or pollution. • foods like yogurt, cottage & Swiss cheese, buttermilk are made from bacteria that grows in milk.
Bacillus anthracis - rod, vegetative stage prokaryote (bacterium) Image Number: 21185 A.
Neisseria meningitidis coccus prokaryote (bacterium) Image Number: 97214 E
Leptospira interrogans - spiral shaped prokaryote (spirochete)
Ecoli movement animatoin
r u o y r o f u o y k n a *Th * n o i t n e t t a
- Slides: 27