Cell biologyLesson 1 of 3 in the course Cell Structure and Function

Microscopy, Cell Organization, and the Foundations of Cell Theory

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Most cells are too small to see with the naked eye, so biologists use microscopes to observe them. Different microscopes reveal different features, and the choice of instrument depends on what a scientist wants to study.

A microscope is an instrument that magnifies an object. Images of specimens captured through microscopes are called micrographs. Cells vary in size, but most are too small to be seen without magnification.

All flashcards

What is the difference between magnification and resolving power?
Magnification is how much an image is enlarged. Resolving power is how well the microscope distinguishes two nearby structures as separate.
Why are stained cells often easier to examine with a light microscope?
Many cells are transparent, so their parts are difficult to distinguish. Stains add contrast, although staining usually kills the cells.
What is an inverted image in a light microscope?
It is an image that appears upside-down and reversed from left to right compared with the specimen on the slide.
How do SEM and TEM images differ?
A scanning electron microscope (SEM) reveals surface characteristics by scanning across the specimen. A transmission electron microscope (TEM) sends electrons through the specimen to show internal structures.
What does a cytotechnologist do?
A cytotechnologist examines cells using microscopes and laboratory tests, identifies normal or abnormal changes, and consults a pathologist when findings may need clinical diagnosis.

Quiz questions

  1. What is a micrograph?Answer: An image of a specimen taken using a microscope.
  2. Which statement is one of the principles of cell theory?Answer: The cell is the basic unit of life.
  3. Why can't electron microscopes be used to observe living cells?Answer: Specimen preparation kills cells, and electron imaging requires a vacuum.
  4. A student wants to examine the surface texture of a prepared cell in great detail. Which instrument is most appropriate?Answer: A scanning electron microscope
  5. A stained cell sample shows changes that may indicate disease. What is the appropriate role of the cytotechnologist?Answer: Identify and report cellular abnormalities, consulting a pathologist for clinical diagnosis.

Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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