7.1 Flashcards
Q: What is the purpose of using light microscopes in biology?
A: Light microscopes allow scientists to view and study tissues, cells, and larger organelles that are too small to be seen by the naked eye
Why is onion epidermis often used for viewing plant cells under a microscope?
A: Onion epidermis is ideal for viewing plant cells because it forms a layer just one cell thick, making it easier to observe individual cells.
Q: What are the key components of an optical microscope needed for viewing cells?
A: The key components include the eyepiece lens, objective lenses, stage, light source, coarse and fine focus knobs.
Q: How can dehydration of tissue samples on slides be prevented?
A: Dehydration can be prevented by adding a drop of water to the specimen beneath the coverslip.
What safety precautions should be taken when using stains like methylene blue?
A: Safety precautions include wearing gloves to prevent contact with the skin and ensuring that the stain is not ingested, especially concentrated methylene blue which is toxic.
Q: Why are human cheek cells commonly used for examination under a light microscope?
A: Human cheek cells are plentiful, easy to obtain safely, and relatively undifferentiated, making them suitable for studying main cell structures.
Q: What safety considerations should be kept in mind when sampling cheek cells?
A: Sampling should not be done on individuals with infections to avoid spreading the infection. Methylene blue solution should be handled with care and kept away from children.
Q: What parts of the cell can be seen with a light microscope?
A: Parts such as the nucleus, mitochondria, cell membrane, and cytoplasm can be seen with a light microscope.
Q: How can the size of cells and organelles be measured under a microscope?
A: The size of cells and organelles can be measured using a calibrated graticule, which includes an eyepiece graticule and stage micrometer.
Q: What are the limitations of optical microscopes?
A: Optical microscopes may show inconsistent sizes of cells or structures in different slides, and they have limitations in magnification power compared to other types of microscopes. Additionally, the treatment of specimens during slide preparation could alter cell structures
