Bacteria 

Summary

1. What are bacteria?
2. Types of bacteria
3. Parts of Bacteria
4. Where do bacteria live?
5. How do bacteria reproduce?
6. Main Characteristics
7. Fun Facts
8. Thanks

1. What are Bacteria? 

Bacteria are single celled microbes. 

The cell structure is simpler than that 

of other organisms as there is a nucleus or 

embrane bound organelles. Instead their control 

centre containing the genetic information is

contained in a single loop of DNA. 

Some bacteria have an extra circle of genetic 

material called a plasmid. 

The plasmid often contains genes that give the 

bacterium some advantage over other bacteria.For 

example it may contain a gene that makes the 

bacterium resistant to a certain antibiotic.

2. Types of Bacteria

Bacteria are classified into 5 groups according 

to their basic shapes: 

   -> Spherical (cocci)

-> Rod (bacilli)

-> Spiral (spirilla)

-> Comma (vibrios) 

-> Corkscrew (spirochaetes)

They can exist as single cells, in pairs, chains or 

clusters.

3. Parts of Bacteria

   

Capsule - Found in some bacterial cells, this 

   additional outer

covering protects the cell when it is engulfed by 

   other organisms,assists in retaining moisture,  
    
   and helps the cell adhere to surfaces and 

   nutrients.



Cell Wall - The cell wall is an outer covering 

   that protects the bacterial cell and gives it 

   shape. 



Cytoplasm - Cytoplasm is a gel-like substance 

   composed mainly of water that also contains  

   enzymes, salts, cell components, and various 

   organic molecules. 


Cell Membrane or Plasma Membrane Plasma 

   mebrane surrounds the cell's cytoplasm and 

   regulates the flow of substances in and out of 

   the cell. 


Pilus - Hair-like structures on the surface of the 

   cell that attach to other bacterial cells. Shorter 

   pili called fimbriae help bacteria attach to surfaces. 


Flagella - Flagella are long, whip-like protrusion 

   that aids in cellular locomotion.


Ribosomes - Ribosomes are cell structures 

   responsible for protein production.


Plasmids - Are gene carrying, circular DNA 

   structures that are not involved in reproduction. 


Nucleiod (DNA) - Area of the cytoplasm that 

   contains the single bacterial DNA molecule.

4. Where do bacteria live?

Bacteria are found in every habitat on Earth:


Soil, rock, oceans and even arctic snow. Some

   live in or on other organisms including plants and

animals including humans.


There are approximately 10 times as many

bacterial cells as human cells in the human body.

A lot of these bacterial cells are found lining the

digestive system.

Some bacteria live in the soil or on dead plant

matter where they play an important role in the

cycling of nutrients.

Some types cause food spoilage and crop 

   damage but others are incredibly useful in the  

   production of fermented foods such as yoghurt 

   and soy sauce.

Relatively few bacteria are parasites or 

   pathogens that cause disease in animals and  

   plants.

5. How do bacteria reproduce?

    


Bacteria reproduce by binary fission. In this

process the bacterium, which is a single cell,

divides into two identical daughter cells.

Binary fission begins when the DNA of the

bacterium divides into two (replicates).

The bacterial cell then elongates and splits into

two daughter cells each with identical DNA to the

parent cell. Each daughter cell is a clone of the

parent cell.


When conditions are favourable such as the right

temperature and nutrients are available, some

bacteria like Escherichia coli can divide every 20

minutes.This means that in just 7 hours one 

   bacterium can generate 2,097,152 bacteria. 

After one more hour the number of bacteria will

have risen to a colossal16,777,216. That’s why   

   we can quickly become ill when pathogenic  

   microbes invade our bodies.


6. Main Caractheristics:



1. Simplest organisms: very small size



2. Lack membrane-bound organelles inside the


cell.



3. Have few internal structures that are


distinging under a Microscopy.



4. Genetic imformation is in a circular loop called


a plasmied (instead of having chromosomal DNA)



5. Strong cell walls: resistant to enviromental


changes. 

Video: 

   




7. Fun facts: 

1- Babies are born with no bacteria in their


bodies

   

2- The chlorine in swimming pools isn't


what causes red eyes. It is the chlorine binding


to the bacteria in the water.

3- The average office desk has 400 times


more bacteria than a toilet.

4- There're more bacteria in your mouth than


there are people in the world.

5- The "smell of rain" is caused by a bacteria


called actinomycetes.

6- Mobile phones have 18 times more


bacteria than toilet handles.

7- Chocolate has an anti-bacterial effect on the


mouth and protects against tooth decay.

8- One euro has 3,000 types of bacteria

9- Most antibiotics are made from bacteria

10- Computer Keyboards can carry more than


200 times as many bacteria as a toilet seat

8. Thanks

Internet & google

Biomedical researchs Institute 

Chonbuk National University Medicalschooll


Microbiology online

Wilkipedia

Youtube 


By Martina Pereda, 2019