9/16/2019Lab 51/28Lab 5Microscopes and CellsObjectives1. Learn the structures and functions of intracellular organelles.2. Be able to operature and focus a microscope.3. Be able to prepare slides and identify structures of organisms present on prepared slides.Student Learning OutcomesLearningObjectiveActivity/Assignment that Addresses ObjectiveCriticalThinkingCompare and contrast prokaryotic and eukaryotic cells; compareand contrast protists, plant cells, and animal cellsCommunicationSkillsWritten -- prelab assignmentOral -- information; interaction and communication with teammembers and laboratory instructorTeamworkStudents will be completing explorations as members of a labgroup/team.PersonalResponsibilitycompletion of prelab activities; coming to class preparedCellFundamental Unit of all living systemsCell Theory: all originate from and consist of cellsMicroscopyMicroscopes magnify images and enable students and researchers to visualize cells and structures that would otherwise be invisible to the naked eye. A person with goodeyesight, who knows what he/she is looking can see objects that are about 0.1 mm in length. However, no internal structure or detail of this 0.1 object would be visible.The space shown in red is 1 mm, so theoretically, you should be able to see something 1/10th that width.The compound light microscope is used in the introductory biology labs. It is a light microscope, because visible light is the light source. Microscopes with light sources thathave a smaller wavelength (eg. ultraviolet light) are capable of greater resolution, and higher magnification, than light microscopes. The light source is usually a lamp that isbuilt into the scope. The condenser is a structure on the microscope that functions to concentrate light on the specimen. The microscope is compound because it has multiplelenses. The objective lens is located above the stage/specimen, and magnifies the image, and the ocular lens, that you look through, further magnifies the image. Compoundlight microscopes can magnify an image up to about 1000 times. Electron microscopes, which use electrons (very low wavelength) as a light source, can magnify structuresup to 200,000 times. For a summary of types of microscopes, and their functions, click here.
9/16/2019Lab 52/28Resolution and level of magnification are important aspects of microscopy and in selecting a microscope.The microscopes you will be using are binocular compound light microscopes. Standard magnification of the ocular lenses is 10 times. When looking at your specimen, thetemptation is to close one eye and use only one of the ocular lenses. Those ocular lenses can be adjusted to the width of your eyes. We recommend that you learn to use themicroscopes with both eyes. The nosepiece houses the objective lenses. There are four objective lenses attached to the nosepiece.