Kingdom Bacteria

All are ______and the majority live as ______but some occur in ______. They reproduce mainly ______by ______but can have a ______reproductive stage (______).

Biological Importance of Bacteria

Advantages

1)

Used in the production of cheese, vinegar, yogurt etc…

2)

Used as natural pesticides or added to soils to enrich nitrogen content (nitrogen fixation)

3)

Recycle organic material from dead organisms. Some bacteria are found in our intestines and aid in the digestion process.

4)

Scientists have used bacteria to study cell metabolism and molecular biology.
Engineered bacteria are used to produce useful substances like: insulin, antibiotics, hormones and anti-cancer drugs.

5)

Some bacteria naturally produce substances, which inhibit the growth of harmful organisms (examples: streptomycin, erythromycin)

6)

The process of using bacteria to destroy, transform or immobilized environmental contaminants.

For example, the bacterium Pseudomonas is used in the treatment of wastewater and sewage; a toxic wood preservative can be removed from soil by a bacterium from the genus Flavobacterium.

A relationship between two organisms (such as a bacteria and a human or plant or animal) is called a ______. In cases in which both partners benefit from the interaction it is referred to as ______.

Disadvantages

1)

The action of bacterial decomposers can cause food to spoil and become harmful to eat. Example: Clostridium botulinum (Botulism)

2)

Many bacteria are ______. These bacteria can also be termed ______, meaning that one organism (the parasite) benefits at the expense of another organism (the host), which is often harmed but usually not killed.

These pathogenic (disease causing) micro-organisms typically produce deadly substances called ______. A toxin is a poison produced in the body of a living organism. It is not harmful to the organism itself but only to other organisms.

There are two types of toxins that bacteria produce, endotoxins and exotoxins.

Endotoxins / Exotoxins

Just one gram of the exotoxin that causes botulism could kill a million people!!!

Classification of Bacteria

Bacteria can be classified using many different criteria. Some of these include:

1) Shape (three types):

These shapes can be arranged in patterns or groupings:

2)Metabolic Needs

Classification based on:

  • Whether they are heterotrophs or autotrophs
  • Do they need oxygen? (aerobic or anaerobic)
  • Special food sources – carbon, nitrogen etc…

Examples:

Term / Description
Needs oxygen
Die when exposed to oxygen
Can grow with or without oxygen
Use light as an energy source
Use chemical compounds as an energy source
Feed on dead organisms or organic waste
Grow in temperatures above 50oC
Grow best in temperatures below 15oC
The Shapes of Bacteria

Thousands of different types of bacteria are known and have been observed. Scientists can tell these organisms apart by the shape of the bacteria or by the way they join together. Write the meaning of the following terms.

1.bacillus ______4. diplo ______

2.coccus ______5. strepto ______

3.spirillum ______6. staphylo ______

Use the terms you defined above to name the bacteria in each diagram below. Write the name on the line below each diagram. Note: Some names will combine two of the terms. For instance, a chain (strepto) of round (coccus) bacteria is called a streptococcus.

______

______

______
3) Colony Morphology

Describes the appearance of a colony in a Petri dish. Such as:

4) Reaction with Gram Stain

  • Gram __ retain crystal violet stain (______) - contain a ______layer in their ______
  • Gram - do not retain crystal violet stain (____) - ______ layer in their cell wall

5) Presence/Absence of:

Flagellum -

Capsule -

6) Spore Formation

Diagram of a Bacterium