Harmful Bacteria
There are also ways that bacteria can be harmful to humans and other animals. Various
speciesofbacteriaareresponsibleformanytypesofhumanillness, includingstrepthroat, tu-
berculosis, pneumonia, leprosy, and Lyme disease. The Black Death (also known as Plague),
which killed at least one third of Europe’s population in the 1300’s, is believed to have been
caused by the bacteriumYersinia pestis.
Bacterial contamination can also lead to outbreaks of food poisoning. Raw eggs and un-
dercooked meats can contain bacteria that can cause digestive tract problems. Foodborne
infection can be prevented by cooking meat thoroughly and washing surfaces that have been
incontactwithrawmeat. Washingofhandsbeforeandafterhandlingfoodisalsoimportant.
Some bacteria also have the potential to be used as biological weapons by terrorists. An
example is anthrax, a disease caused by the bacteriumBacillus anthracis. Since inhaling the
spores of this bacterium can lead to a fatal infection, it is a dangerous weapon. In 2001, an
act of terrorism in the United States involvedB. anthracisspores sent in letters through the
mail.
Lesson Summary
- Bacteria contain a cell wall containing peptidoglycan and a single chromosome con-
tained in the nucleoid. - Bacteria can obtain energy through several means including photosynthesis, decompo-
sition, and parasitism, symbiosis, and chemosynthesis. - Bacteria reproduce through binary fission.
- Bacteria are important decomposers in the environment and aid in digestion.
- Some bacteria can be harmful when they contribute to disease, food poisoning, or
biological warfare.
Review Questions
- What are prokaryotes?
- What are the possible shapes that bacteria can have?
- What is the purpose of the flagella?
- Describe the DNA of bacteria.
- How do bacteria reproduce?
- How do bacteria assure genetic recombination?
- What is a chemoautotroph?
- How do cyanobacteria obtain energy?
- How are bacteria important in nature?
- How can you avoid becoming sick from the bacteria that cause food poisoning?