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- - There are two main types of cells:
- ) Prokaryotic cells, found in bacteria, are small, simple cells that lack a well-defined nucleus and most organelles.
- ) Eukaryotic cells are found in plants, animals, fungi, and single celled organisms called protists.
- Eukaryotic cells have an outer membrane;; a nucleus, which contains the chromosomes; and organelles.
-Each organelle carries out a specific tassk to maintain the cell as a living entity.
-Animal cells must take in food to obtain energy to reproduce and grow.
-Plant cells use structures called chloropplasts to make food for themselves by trapping the Sun's energy.
- Cell Organelles and their Functions
Ribosomes
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synthesize proteins
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Endoplasmic Reticulum
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transports materials within the cell
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Golgi Bodies
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stores secretions, modifies protein
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Mitochondria
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releases energy
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Nucleus
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controls all cell activities, including reproduction
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Chloroplasts
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carry on photosynthesis
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Lysosomes
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digest materials in cells
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Vacuoles
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store water & dissolved molecules
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Cytoskeleton
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movement & support
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Cilia & Flagella
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movement
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- Biologists use different types of microsscopes and various tools and techniques to study the structure and function of cells.
- The compound light microscope illuminatees a specimen with a beam of light. Two sets of lenses, the ocular (located in the eyepiece) and the the objective (located above the specimen), magnify a specimen which is mounted on a prepared slide.
- - Two important concepts relating to microscopes:
- ) Magnification is the ability of a microscope to make an image appear larger.
- ) Resolution is the ability to show details clearly.
- An electron microscope uses a beam of ellectrons instead of light rays to produce an image magnified at least 100 times more than a light microscope.
- Scanning electron microscope (SEM) reveaals surface details of specimens.
- Transmission electron microscope (TEM) rreveals the internal structure of specimens
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