Pure Culture Methods and Gram Staining Discussion Essay Assignment
Pure Culture Methods and Gram Staining Discussion Essay Assignment
1) Bacillus cereus was obtained from the big bacteria colony. When observed from the agar plate, it appeared to be irregular in shape, flat, opaque and cream in colour. It is a gram positive bacteria. So when gram stain was performed, the bacteria appeared purple in colour under the microscope. Bacillus cereus is of rod shape and the arrangement is in the form of chain. It has β- capsule and is non motile. For Escherichia coli, it was obtained from the medium colony. When observed from the agar plate, it appeared to be circular in shape and mostly was located at the center of the agar. The bacteria colony appeared to be smooth, translucent, and some were white in colour (Cham & Tan, Group 1). Escherichia coli is a gram negative bacteria. Pure Culture Methods and Gram Staining Discussion Essay Assignment. Therefore, it was pink in colour under the microscope. It has rod shape and its arrangement is in cluster form. It is motile and is a type of non spore forming bacteria. Staphylococcus aureus was from the small bacteria colony. It is circular, smooth, convex and some are yellow in colour while some are white in colour. It is a gram positive bacteria where it showed purple colour when under the microscope. The shape for Staphylococcus aureus is cocci and it is in cluster form. It is a non spore forming bacteria and is non motile. The cells seen in the original mixture matched with those obtained in the pure culture. Pure Culture Methods and Gram Staining Discussion Essay Assignment
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Streak plate method is suitable for the direct plating of media that contains a large number of cells and as for spread plate method, a small volume of suspension is spread evenly over the surface of an agar plate. On the other hand, bacteria are suspended and grow throughout the agar plate for pour plate method. 2) Spread plate will be more suitable to produce well isolated single colonies from a broth culture that contains a mixture of organisms as the bacteria will be on the surface or the agar and not suspended. This way, the isolated colony can be counted and also be obtained easily compared to streak plate and pour plate method. When the bacteria is taken from a mixed broth culture, the colonies will grow and overlapping each other after being incubated. When the bacteria is incubated using pour plate method, the bacteria grown will be smaller and it will be harder to obtain a well isolated colony as they grow throughout the media. Pure Culture Methods and Gram Staining Discussion Essay Assignment
Agar has a higher melting temperature than gelatin. Gelatin will melt and becomes soft when bacteria is being incubated on gelatin media at their optimum temperature which is 37 â°c. 3) Agar is used in preference to gelatin for making solid media as agar will remain solid at the optimum temperature for the growth of most bacteria. Therefore, the property of agar makes it to be more effective than gelatin as a solidifying agent (Muir & Ritchie, 1953). Pure Culture Methods and Gram Staining Discussion Essay Assignment
1) Bacillus cereus was obtained from the big bacteria colony. When observed from the agar plate, it appeared to be irregular in shape, flat, opaque and cream in colour. It is a gram positive bacteria. So when gram stain was performed, the bacteria appeared purple in colour under the microscope. Bacillus cereus is of rod shape and the arrangement is in the form of chain. It has β- capsule and is non motile. For Escherichia coli, it was obtained from the medium colony. When observed from the agar plate, it appeared to be circular in shape and mostly was located at the center of the agar. The bacteria colony appeared to be smooth, translucent, and some were white in colour (Cham & Tan, Group 1). Escherichia coli is a gram negative bacteria. Pure Culture Methods and Gram Staining Discussion Essay Assignment. Therefore, it was pink in colour under the microscope. It has rod shape and its arrangement is in cluster form. It is motile and is a type of non spore forming bacteria. Staphylococcus aureus was from the small bacteria colony. It is circular, smooth, convex and some are yellow in colour while some are white in colour. It is a gram positive bacteria where it showed purple colour when under the microscope. The shape for Staphylococcus aureus is cocci and it is in cluster form. It is a non spore forming bacteria and is non motile. The cells seen in the original mixture matched with those obtained in the pure culture. Pure Culture Methods and Gram Staining Discussion Essay Assignment
Streak plate method is suitable for the direct plating of media that contains a large number of cells and as for spread plate method, a small volume of suspension is spread evenly over the surface of an agar plate. On the other hand, bacteria are suspended and grow throughout the agar plate for pour plate method. 2) Spread plate will be more suitable to produce well isolated single colonies from a broth culture that contains a mixture of organisms as the bacteria will be on the surface or the agar and not suspended. This way, the isolated colony can be counted and also be obtained easily compared to streak plate and pour plate method. When the bacteria is taken from a mixed broth culture, the colonies will grow and overlapping each other after being incubated. When the bacteria is incubated using pour plate method, the bacteria grown will be smaller and it will be harder to obtain a well isolated colony as they grow throughout the media. Pure Culture Methods and Gram Staining Discussion Essay Assignment
Agar has a higher melting temperature than gelatin. Gelatin will melt and becomes soft when bacteria is being incubated on gelatin media at their optimum temperature which is 37 â°c. 3) Agar is used in preference to gelatin for making solid media as agar will remain solid at the optimum temperature for the growth of most bacteria. Therefore, the property of agar makes it to be more effective than gelatin as a solidifying agent (Muir & Ritchie, 1953). Pure Culture Methods and Gram Staining Discussion Essay Assignment