Topics: Bacteria, Bacterial cell structure, Cell wall Pages: 9 (639 words) Published: October 15, 2014
The prokaryotes

Student name : Lina Qasem AL-hyasat .

Engineer : Ahmad Shrab .


This lab is purposed to familiarize basic equipment and techniques used in the study of microorganisms. In addition, learn some basic techniques used in identifying prokaryotes and make and view microscope slides of some common

In this lab , I worked two experiments , the first one is cultivation bacteria "colony ", and When microorganisms are cultivated in the laboratory, a growth environment called a medium is used , this medium should be sterile ,When grown and isolated by placing onto medium that known as inoculation .The purpose from this experiment is describe isolated colonies.

The second experiment is " Gram stain "m is commonly used to assist in bacterial identification. It is one of the important techniques to classify bacteria .In fact it does distinguished between two different kinds of bacterial cell walls. This staining method separates bacteria into two groups based on the thickness of their cell wall.

Materials and methods

Isolation of bacteria equipment :

Agar plate & petri dish & broth

Ethanol 70 %


Bunsen burner

Wire loop


Gram stain equipment :
-Crystal violet
-Idoine solution
- Qil immersion
-Compound microscope

Staining method

-Obtained slide and put a drop of water into it .
- Put inoculation bacteria onto slide.
- Put the slide onto low flame even dry.
-Added crystal violet and dyed for one minute.
-Added iodine solution and dyed for one minute.
-Washed with alchole , dyed for 10-30 seconds.
Note: here make sure if the slide transparent.
-washed with water.
-Added safranine solution and dyed for 30 seconds.
-waited even dryed.
-Added one drop of oil immersion.
-put the slide on the stage of compound microcope.
-finaly,watched the slide.

Isolation of bacteria method

-wiped working area with disinfectant.
-Obtained a sterile petri dish of nutrient agar,kept led on ,and used the marker to divided the petri dish ,into teo sector. -opened lte lid slightly,inoculate sector number 1 with thumbprint. -Taked sterial wire loop to transferred colony from a broth to an agar plate. -The loop should be cooled in the air for 10 to 20 sec and placed on the line drawed. -Remove a sample from a broth culture by using a sterile wire loop. -Transferred the sample from borth to agar plat.

- When inoculated an agar plate, drawed the loop very lightly over the surface while being careful not to break the surface. A zig-zag motion used. -The name wrote on the plate ,then placed it's into incubator in a 37 degree incubator for 48 hours.

Result of Gram stain:

Result of Isolation of bacteria in the following pictures :

Disscusion :

Microorganism are organism that are too small and cannot be seen with naked eyes, are everywhere in our daily life surrounding. They are in the air we breath,the foods we eat. Aseptic transfer is the transference of bacteria or other microbial cultures from one container to another while maintaining purity of the culture. The scientist is left working with mixed cultures. Pure cultures can be derived from mixed cultures through isolation of cultures and this also requires that sterile (aseptic)techniques to be used. Normally transference is done from colonies. A colony consists of usually several million cells that are assumed to be the descendants from one cell Inoculations from one media to another, therefore, is usually done by removal of a few million cells from one colony into a new environment. This must be done with the integrity of all colonies remaining intact. Through the use of sterile techniques, this can be accomplished...
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