Lab 1 - Lab Report on Microscopy PDF

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Lab Report on Microscopy...

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Introduction: Almost every single microbe that exists is impossible to see with the naked eye, due to the fact that they’re invisible. In order to actually see them, the use of a microscope is necessary, as well as knowing how to use one. There are multiple variations of a microscope, however, for the sake of this lab a compound/binocular microscope was used—a microscope that has two lenses between the eye and the slide. This allows for magnification to occur and adequate lighting, that work hand-in-hand for easier viewing. For this lab, in order to view the specific microbes, the following “instruments” were used on the microscope: the base (which includes the light source, the stage (to hold the slide), the iris diaphragm (allows for controlling of the light needed to see the specimen), objective lenses (held by a revolving nosepiece that allows for proper magnification, and an eyepiece lens (for which to see through, and this one had two lenses). There was also the coarse adjustment knob (used for focusing low-power objectives [4x and 10x]), and the fine adjustment knob (used for focusing the high power and oil immersion lenses). There was also the magnification, which are on the revolving nosepiece, to help zoom onto the specimen and ranges from 4x to 100x. A eukaryote is an organism that is a complex cell, and the genetic material involved is contained within a membrane-bound nucleus or nuclei. In contrast, prokaryotes cells lack a nucleus and other membrane-bound structures. Both prokaryotic and eukaryotic cells are enclosed by a cell membrane and use DNA for genetic information. Bacterium are single-celled microbes, and their cell structure is simpler than other organisms because there is no nucleus or membrane-bound structures present. All of their genetic information is contained in one coil of DNA.

The objective for this lab was to observe microbes, more specifically eukaryotes and bacteria and prokaryotes, under a microscope and observe their shapes and colors. Materials and Methods: For this lab, the materials and procedure from page 12, exercise 1 were used. The only part that was modified was the number of slides observed of each organism (3 eukaryotes, 1 prokaryote, and 1 bacterium), and taking pictures instead of physically drawing the cells out. Results: The first eukaryote that was observed was Paramecium caudatum (protozoan). It’s shaped like a cigar, and the back of the body is pointed and thick while the front of the body is rounded. The widest part of it is in the middle, right near where the nucleus is visible. The entire specimen is in clustered, and it’s difficult to find one that’s isolated. Due to one side being pointed and thick while the other being rounded, it makes the entire body seem asymmetrical. The color is also seen as a light purple, with the nucleus being dark purple. This can all be seen through a 10x magnification. Once magnified at 40x, P. caudatum is seen to be fairly the same as at a 10x magnification. Once magnified at 100x with the immersion oil, there can be some cilia that can be seen. However, only light traces of the cilia can be seen towards the left-most specimen right towards the back of the body. The second eukaryote that was observed was Chlamydomonas (alga). At 10x magnification, the color seemed to be purple with the shape being seen as dots. Most of the specimen was clustered together towards the edges of the slides and the middle, with the “outer middle” being isolated. In some of the “spots” a darker purple tinge could be seen, which is the nucleus. At 40x magnification, the nucleus itself become a bit clearer and the dots seemed to be

almost perfect circles. At 100x magnification with the immersion oil, the specimen seemed to be perfectly rounded dots that were almost entire comprised of the nucleus. There were still some clusters present, but there was a wide gap before another cluster started, and some of the specimen was in a line. The third, and final, eukaryote that was observed was Rhizopus (fungus). At 10x magnification, the shape was almost sperm-like. There was a head, which consisted of the nucleus, and then a long “string” attached to it. There were clustered that overlapped over each other, and then some spaces with only one specimen there. The color was almost like a cross between red and maroon—bright but not at the same time. At 40x magnification, the head of the specimen seemed to have the nucleus in only half of it, with the string that was attached to it sort of fading out towards the back. At 100x magnification with the immersion oil, it was clear that the head had smaller dots present inside of it, and the dots were also closer together in some places than not. The bacterium that was observed was Spirillum volutans (spiral-shaped bacterium). At 100x magnification with the immersion oil, the shape comprised of wiggly lines and multiple dots ranging from small to large. The color was purple, and the shapes overlapped each other in some places. However, there were some places where there wasn’t a lot of bacterium, it was almost like there was a group of it, and then a space where there was almost nothing, and then continued on like that. The places that had a lot of bacterium in it, though, comprised of a lot of wiggly lines and multiples dots that were overlapping each other.

Literature Cited Johnson, & Case. (2018). Microbiology Lab Manual (11th Edition). Boston: Pearson Collections. Amazon Kindle.

Pictures of Eukaryotes, Prokaryote, and Bacterium Paramecium caudatum (protozoan) at 10x

Paramecium caudatam (protozoan) at 40x

Paramecium caudatum (protozoan) at 100x

Spirillum volutans (spiral shaped bacterium) at 100x

Rhizopus (fungus) at 10x

Rhizopus (fungus) at 40x

Rhizopus (fungus) at 100x

Chlamydomonas (alga) at 10x

Chlamydomonas (alga) at 40x

Chlamydomonas (alga) at 100x...