Magnifying and Observing Cells
Every living thing is composed of cells, the microscopic building blocks of life. In fact, most life forms exist as single cells that carry out all functions needed for their own independent existence. Examples of common single-celled organisms are bacteria (tiny organisms found in almost every habitat on Earth), diatoms (algae that are common components of phytoplankton), and yeast (a kind of fungus). Multicellular organisms consist of several to many cells. Single-celled and small multicellular organisms, which must be magnified to be observed, are called microbes or microorganisms.
Plants and animals are examples of multicellular organisms visible to the naked eye. These macroscopic multicellular organisms can have up to trillions of cells that carry out specialized functions.
This activity uses plant cells, because many of these are relatively easy to see. Students will observe onion cells (in the thin membrane around each onion “ring”) and a leaf from Elodea. With these examples, students will be able to see basic parts of cells, including the nucleus (structure in the center of the cell that holds hereditary information), cytoplasm (gel that fills the cell), cell wall (rigid outer boundary of plant and other kinds of cells), and chloroplasts (large green structures in which photosynthesis occurs).
Keywords: microscope | microscopic | Elodea | onion skin | microbe | microorganism | cell | cells | nucleus | cell wall | cytoplasm | chloroplast | organelle | photosynthesis | microbiology | plants | cells
- Moreno, N., Tharp, B., Erdmann, D, Rahmati Clayton, S., and Denk, J. (2012) The Science of Microbes Teacher’s Guide. Baylor College of Medicine: Houston. ISBN: 978-1-888997-54-5
- Photo courtesy of the USDA Natural Resources Conservation Service/R. Mohlenbrock © PLANTS Database.
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Grant Number: 5R25RR018605