Under the Microscope

Table of Contents

1.0        Introduction        

1.1 Background Information        

1.2 Variables        

1.3 Hypothesis        

2.0        Materials        

3.0 Procedure        

4.0 Results        

4.1 Classifcation Key        

4.2 Observation Table        

5.0 Discussion        

6.0 Conclusion        

7.0Appendix        

7.1 Appendix 1        

1. Introduction

The purpose of this experiment is to identify two unknown samples of bacteria.

1.1 Background Information

When discovering the unknown bacteria a variety of experiments will be undergone. The gram stain was first used in 1884 by Hans Christian Gram (Hussey, 2013). This procedure distinguishes organisms and bacteria according the the structure of the cell wall (Hussey, 2013). Gram-positive cells have a thick peptidoglycan layer and stain blue to purple whereas gram-negative cells have a thin peptidoglycan layer and stain red to pink (Hussey, 2013). Hydrolysis of starch is done to differentiate bacteria based on their ability to hydrolize starch (Lewis, 2013). Starch molecules are too large to enter the bacterial cell, so some bacteria excreet enzymes to degrade starch into little particles that can be used by the enzymes (Lewis, 2013). When iodine is poured onto the starch plates the bacteria that underwent the fermentation of carbohydrates should stay the same whereas if the bacteria cannot ferment carbohydrates the bacteria should turn black (Lewis, 2013). Phenol red glucose is used to determine whether bacteria can use the glucose for carbon and energy, and see whether the bacteria can ferment glucose (BH, 2011). If when added it turns yellow it ferments glucose although if it stays a pinky red colour that means that bacteria degrades amino acids (BH, 2011). Robert Koch made a set of criteria that could be use to discover the pathogen responsible for a specific disease.  Classification is when living things are classified into groups (SCIPE, 2012). When classifying bacteria they were put into groups based on their shape, gram-staining and its respiration method (SCIPE, 2012).