4 QUESTIONS AND ANSWERS
1. Light microscrope: A microscope that passes visible light through the specimen and then
through glass lens, which refracts light so the image of the specimen is magnified as it's projected
into the eye or camera.
2. Magnification: Ratio of an object's image size to its real size
3. Resolution: Measure of the clarity of an image
4. Contrast: Ditterence in brightness between the light and dark areas of the image
5. Cell theory: All living things are composed of cells; all cells come from other cells; the cell is the basic
structural
and functional unit of all living things
6. Organelle: Membrane-enclosed structures within eukaryotic cells
7. Electron microscope (EM): Microscope that focuses a beam of electrons through the
specimen
8. Scanning electron microscope (SEM): Microscope that uses the electron beam scans the
surface
of the sample, usually coated with a thin film of gold, which excites electrons on the surface, and
these secondary electrons are detected by a device that translates the pattern of electrons into an
electronic signal sent to a video screen
9. Transmission electron microscope (TEM): Microscope that aims an electron beam
through a
very thin section of the specimen, much as a light microscope aims light through a sample on a slide, to
study internal structure of cells
10. How big are cells, bacteria, organelles?: 1-100 micrometers (µm)
11. Cytology: Study of cell structure
12. Biochemistry: Study of chemical processes of cells
13. Cell fractionation: Technique in which cells are broken into pieces and the ditterent cell
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, CAMPBELL BIOLOGY IN FOCUS (3RD EDITION) - CHAPTER
4 QUESTIONS AND ANSWERS
parts are
separated
14. Cytosol: Fluid portion of cytoplasm
15. Chromosomes: Threadlike structures made of DNA molecules that contain the genes
16. Nucleoid: Non-membrane-bounded region in a prokaryotic cell where the DNA is
concentrated
17. Cytoplasm: Interior of either type of cell
18. ary the
Plasma membrane: Selectively-permeable phospholipid bilayer forming of the cells
bound
that
allows oxygen, nutrients, wastes passage
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