Experiment 2 Microscopy VY NGUYEN 5 February 2016 ABSTRACT 1. Handle the microscope safely and know how to clean it. 2. Explain principles and terms used in light microscopy and focusing 3. Identify and know the functions of the major parts of compound microscope. 4. Examine biological specimens using wet mount techniques. 5. Understand the distinguishing cell sizes and other structural features between prokaryotic and various eukaryotic cell types. Vy Nguyen Experiment 2: ​
Microscopy​
Review 1. Be able to find an anaphase cell of onion root tip under 40X. 2. Be able to identify the important parts of a microscope and describe the functions of each. Ocular lense​
s – The lenses you look into (10X are used in this lab) Objective lense​
s – The binolars Condenser lenses​
­ to focus the light onto the specimen Concentric X­Y control knobs​
– to move the specimen forward/back or left/right Aperture (iris) diaphragm​
– to secure illumination and contrast Coarse and Fine focusing Knobs​
– to raise or lower the stage in larger or smaller increments to bring the specimen into focus. Substage condenser: ​
to gather the light coming from the light source and to concentrate that light in a collection of parallel beams onto the specimen Interpupillary distance adjustment:​
to set the interpupillary distance for your eyes. Diopter adjustment:​
used to suit the eyesight of the user 3. How do you calculate total magnification? Total magnification of an object observed through the eyepieces (ocular lens) is calculated by multiplying the ocular lens magnification times the magnification of the objective lens being used (either: 4X, 10X, 20X, 40X, 100X, etc.). “X” is placed after obtaining the total magnification number. Example: Ocular lens magnification = 10X Objective lens magnification being used = 4X Total magnification? Calculation: (10X)(4X) = 40X Page 1 Vy Nguyen 4. Understand how Depth of Field and Field of View change if magnification increases. As magnification increases, depth of field and field of view both decreases. 5. Know the cellular features that differentiate plants from animals. Plant cells have chloroplasts, a cell wall, and centrioles. 6. Know the relative cell sizes among bacteria cells and eukaryotic cells. Bacterial cells are very small ­ about 10 times smaller than most plant and animal cells. Most bacterial cells range in size from 0.2 to 10 micrometer. 7. Be able to identify the following on prepared slides. Know which ones are prokaryotes. a. Bacterial cells and their shapes under oil immersion (PROKARYOTES) BACILLUS (rod) COCCUS (SPHERE) HELICES Page 2 Vy Nguyen b. Human cheek cells (EUKARYOTE) c. Diatoms (EUKARYOTES) Page 3 Vy Nguyen d. Spirogyra (EUKARYOTES) e. Amoeba (EUKARYOTES) Page 4 Vy Nguyen f. Paramecium (EUKARYOTES) g. Budding yeast (EUKARYOTES) Page 5 Vy Nguyen h. Rhizopus (EUKARYOTES) i. Penicillium (EUKARYOTES) Page 6