e-portfolio fourth week (experiment 4 and 5)

Experiment 4:Microscopic examination of stained cell preparation
During the fourth experiment, I have the chance to use the compund light microscope.We are told how to handle the microscope carefully.When holding the microscope,we need to put one hand at the arm of the microscope while the other hand at the base of the microscope.Then,we put the mciroscope at our bench.We were given some prepared slides of Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, slide  of blood smear and slides of Saccharomyces cerevisiae.We observe the slide starting by using magnification of 40x,followed by 100x, 400x and 1000x(oil immersion).

Pictures of compound light microscope

Slide of Staphylococcus aureus (high power)

 Slide of Saccharomyces cerevisiae (high power)

 Slide of Bacillus subtilis (high power)

 Slide of Bacillus cereus (high power)

 Slide of Saccharomyces cerevisiae

 Slide of red blood cell

Experiment 5:Microscopic Examination of Living Microorganisms Using a Hanging-Drop Preparation or a Wet Mount

In this experiment,I learnt how to prepare a hanging-drop and wet mount.To prepare the hanging-drop,I have to spread a ring of petroleum jelly around the concavity of the depression slide.Then,I place of loopful of the bacterial culture in the center of the coverslip. Then,I lower the depression slide,with the concavity facing down,onto the coverslip and press gently to form a seal.Finally,I turn the hanging-drop preparation over so that the culture drop adheres to the coverslip.For the wet mount,

I use the cotton swab to apply a thin layer of petroleum jelly along the edge of the four sides of a coverslip.Then,by using the aseptic techniques,I place a loopful of the culture in the center of the coverslip.After that,I place a clean glass slide over the coverslip and press the slide gently to form a seal between the slide and coverslip.Next,I turn the wet mount preparation slide over so that the culture drop adheres to the coverslip.We did the hanging drop and wet mount preparation for the broth cultures of P.aeruginosa, B.cereus,S.aureus,,P.vulgaris,hay infusion and pond water.I observe it under high power and oil immersion and record the observation in a table.

Slide of Bacillus cereus

 Slide of S.aureus