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Bacteria

 

 

Most bacteria we know belong to the Bacteria domain which contains the Eubacteria Kingdom that is divided into different groups according to their biochemical composition, their shape and the way they get energy.  

 

There is a wide amount of bacteria that actually biologists still ignore.  Many of them can cause disease, you can check your vaccination card and observe which diseases are caused by bacteria, and which ones by viruses, but some others are very helpful and play an important role in nature, or even in the body of other organisms.

Lactobacillus 

(genus Lactobacillus), any of a group of rod-shaped, bacteria.  Lactobacillus are characterized by their ability to produce lactic acid as a by-product of glucose metabolism.

Escherichia coli or E. coli 

is a bacterium that can be found in  

soil and in the large intestines of many mammals, including humans. Most strains of E. coli do not cause disease, but instead help animals get vitamins and digest food. 

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Introductory Questions

 

  1. What do you know about bacteria?

  2. How do bacteria obtain energy, and what can we get from this process?

  3. Are all bacteria harmful?

  4. How can we use bacteria to obtain milk products?

  5. Which is the role of bacteria in an ecosystem?

 

Bacteria are prokaryotic organisms (proto=primitive-Karyon=nucleus) that are usually anaerobic (they don't need oxygen to obtain energy), intead, they decompose glucose and some other sugars into lactic acid, acetic acid or ethanol by a process called fermentation. 

From fermentation, ancient cultures had developed techniques to obtain foods and beverages like milk products, preserved vegetables and alcohol.  

Bacteria help in the decomposition of organic matter within a food chain, apporting minerals to the soil.

Activity

1. Observe the pictures and use them to answer the questions.

2. Discuss with your classmates in groups of 3, about the different answers to the given questions.

3. Share the information with the class and make a mental map about some applications of bacteria.

 

Key words:

 

Prokaryotes

Decomposers

fermentation

aerobic - anaerobic respiration.

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