Microscope Flashcards
Q: What is a light microscope?
A: A light microscope is a coordinated system of lenses arranged to produce an enlarged, focusable image of a specimen.
Q: What does magnification mean in light microscopy?
A: Magnification is the increase in apparent size of a specimen
What is resolution in microscopy?
A: Resolution is the ability to distinguish two points as separate, providing a sharper or crisper image.
What is the resolving power of the unaided human eye?
A: Approximately 0.1 mm.
Why is contrast important in microscopy?
A: Contrast allows the difference between the lightest and darkest parts of an image to be seen, improving detail visibilit
Q: How is contrast often enhanced in specimens viewed under a light microscope?
A: By staining specimens with artificial dyes
Q: Why was the invention of the light microscope important to biology?
A: It helped formulate cell theory and allowed the study of cellular structures.
What are the main systems of a compound light microscope?
A: Illuminating system, imaging system, and sometimes a viewing and recording system.
Why is the light microscope considered a fundamental tool for biologists?
A: It allows observation of structures too small to be seen with the unaided eye, essential for biological studies.
How much can a light microscope improve resolution compared to the unaided eye?
A: Up to 1000-fold, improving resolution to 0.1
What is the purpose of the imaging system in a microscope?
A: It improves resolution and magnifies the image.
What components make up the imaging system in a compound light microscope?
A: The objective lenses, ocular (eyepiece) lenses, and body tube.
Q: What are the typical magnifications of objectives on student microscopes?
A: Low magnification (4x), medium magnification (10x), high magnification (40x), and oil immersion (100x).
What are objective lenses?
A: Lenses mounted on a revolving nosepiece that magnify the image, improve resolution, and correct image aberrations.
What is required when using the oil immersion objective?
A: Special instructions, as oil immersion is typically used for studying bacteria.
Where can you find the magnifying power of each objective lens?
A: It is etched on the side of each lens (e.g., 4x, 10x, 40x, 100x).
What is the ocular lens, and what does it do?
A: The ocular lens is the lens you look through, typically magnifying the image by 10x.
What are the differences between monocular and binocular microscopes?
A: Monocular microscopes have one ocular, while binocular microscopes have two oculars.
What is the body tube in a microscope?
A: A metal casing that channels light to the oculars.
What does the body tube contain in microscopes with bent tubes and inclined oculars?
A: Mirrors and a prism to redirect light to the oculars
What is the function of the stage in a microscope?
A: It secures the glass slide on which the specimen is mounted
What is the purpose of the illuminating system in a microscope?
A: To concentrate light on the specimen.
What are the main components of the illuminating system?
A: The light source, condenser lens, and iris diaphragm.
Where is the light source located on a microscope?
A: At the base of the microscope.
What does the light source do in a microscope?
A: It illuminates the specimen by passing light through a thin, nearly transparent part of the specimen.
What is the function of the condenser lens?
A: To focus light onto the specimen.
Where is the condenser lens positioned in relation to the specimen?
A: Immediately below the specimen.
What role does the iris diaphragm play in the illuminating system?
A: It controls the amount of light reaching the specimen.
What is a key advantage of a dissecting (stereoscopic) microscope over a compound microscope?
A: It has a larger working distance, allowing easier manipulation of specimens.
What is “working distance” in microscopy?
A: The distance between the objective lens and the specimen.
What type of specimens are best observed with a dissecting microscope?
A: Opaque or larger specimens that are too thick for a compound microscope.
How does the working distance of a dissecting microscope compare to that of a compound microscope?
A: It is usually several centimeters, much larger than a compound microscope’s working distance.
Where is the light source positioned in a dissecting microscope, and why?
A: Above the specimen, to provide reflected light suitable for viewing thick specimens.
Are dissecting microscopes monocular or binocular?
A: Dissecting microscopes are always binocular.
What kind of image does a dissecting microscope provide?
A: A three-dimensional image with a large depth of field.
How does the image depth of field in a dissecting microscope compare to that of a compound microscope?
A: The dissecting microscope has a larger depth of field, while a compound microscope provides a two-dimensional image.
