Lab Report 1 by Ooi Sin Ying

Name           : Ooi Sin Ying
No. matrice : 111410

1.1 Setting up and using the microscope

Introduction :
In order to be seen, microorganisms need to magnified. Despite advances in other area of  microscopy  (for example, the electron microscope), the light microscope is still the instrument most frequently used for viewing microorganisms.

Objective     :
Learn to use a simple bright-field microscope correctly.

Result           :

1. 4xobjective X 10xobjective = 40x magnification

2. 10x objective X 10x objective

3. 40x objective X 10x objective

 Discussion ：

1.The light intensity is adjusted using the brightness control.

2.Specimen is observed from the lowest power objective, 4x magnification followed with 10x

   magnification and 40x magnification.

3.The total magnification of the image is calculated by multiplying the objective lens power by the

   eyepieces lens power.

4.Course-focus and fine-focus adjustment knobs are rotated to raise and lower the mechanical stage

   so that the objective lens is focused on the specimen. Fine-focus knob is used to moves the stage

   while looking through the microscope.

5.Morphology of the Salmonella enteritidis :

  -Shape    : circular

  -Size       : tiny and punctiform

  -Surface : shining and smooth

  -Colour  : red

Conclusion :

Each parts of the microscope has their own function in giving the best view of specimen. The higher the magnification of the objective lens the clearer and larger view of specimen will be provided.

Reference  :

-http://www.bristol.ac.uk/vetpath/cpl/critillum.html

-http://quizlet.com/370451/microbiology-student-presentations-flash-cards/

                   

1.2 Examination of cells

Introduction :
Because of their extreme minuteness, bacteria are not generally studied with the low-power or high-power dry objectives. Instead they are stained and observed with the oil immersion objective.

The wet mount methods enables you to study the sizes and shapesof living microorganisms (drying or staining microorganism distort them). It also enables you to determine if cells are motile. The wet mount method is quick and easy, and does not require special equipment.

Objective     :

-To provide an experience in the use of microscope.

-To illustrate the diversity of cells and microorganisms.

Result          :

Under 100x objective X 10x eyepiece = 1000x magnification

1.Saccharomyces cerevisiae (Yeast)

2.Lactobacillus fermentum

Dicussion  :

1.The oil immersion fills the space between the objective lens and specimen and matches the

    refractive index of the glass coverslip and glass objective lens. At a given focal length, this allows

    me to achieve a greater numerical aperture.

2.Two different microorganism is observed :

    -Saccharomyces cerevisiae (Yeast) and

    - Lactobacillus fermentum

3.Morphology of Saccharomyces cerevisiae (Yeast) :

   -Shape    : circular

   -Size       : tiny

   -Surface : moist and smooth

   -Colour  : lemon yellow

4.Morphology of Lactobacillus :

   -Shape   : rod

   -Size      : tiny

   -Surface : moist and smooth

   -Colour  : violet

Conclusion :

Using oil immersion with 1000x magnification give clearer view of specimen that allow me to see the size, shape and colour of living microorganisms. 

Reference  :

-wiki.answer.com/Q/Why_is_oil_necessary_when_using_the_90x_to_100x_objective.

-http://www.phadia.com/en/Allergen-information/ImmunoCAP-Allergens/Food-of-Plant--Origin/Miscellaneous/Yeast-/

-http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822009000400005