The microscope in cell
9 flashcards to master this topic
Describe the process of making a temporary wet mount of onion epidermal cells for light microscopy.
1. Peel a thin layer of epidermis from the inner surface of an onion. 2. Place the epidermis on a clean microscope slide. 3. Add a drop of water to the specimen. 4. Gently lower a coverslip onto the water at an angle to avoid air bubbles.
Define 'magnification' in the context of microscopy.
Magnification is the number of times larger an image appears compared to the actual size of the specimen. It is calculated by dividing the image size by the actual size.
Define 'resolution' in the context of microscopy.
Resolution is the ability to distinguish between two points that are close together as separate entities. Higher resolution allows for finer details to be observed.
What is the typical range of magnification for a light microscope?
Light microscopes typically magnify from approximately x40 to x1000, depending on the objective lens used.
What is the approximate resolution limit of a light microscope, and what limits it?
The resolution limit of a light microscope is approximately 200nm. This limitation is due to the wavelength of visible light.
Convert 5mm into micrometres (µm).
5 mm = 5 x 1000 µm = 5000 µm. Remember that 1 mm equals 1000 µm.
An image of a cell is 50mm wide. The actual cell is 50µm wide. What is the magnification?
Magnification = Image size / Actual size. Magnification = 50mm / 50µm = 50000µm / 50µm = x1000.
Explain the difference between magnification and resolution.
Magnification makes an image larger; resolution is the ability to see fine details. A high magnification image can still be blurry (low resolution), and a high-resolution image doesn't need to be highly magnified.
Describe one advantage of using a transmission electron microscope (TEM) over a light microscope.
TEMs have a much higher resolution than light microscopes, allowing for the visualization of smaller structures within cells, such as ribosomes and the internal structure of organelles.
Ready to test yourself?
Practice with MCQ questions to check your understanding of The microscope in cell.
Take QuizStudy Mode
Rate each card Hard, Okay, or Easy after flipping.