E2-Study Questions - Chapter 4: Cells: The Working Units of...

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Chapter 4: Cells: The Working Units of Life KEY CONCEPTS 1. The cell is the basic unit of life. All cells come from preexisting cells and have certain processes, types of molecules, and structures in common. 2. Cells may have originated from structures similar to the cell-like structures that can be produced in the laboratory. 3. To maintain adequate exchanges with its environment, a cell’s surface area must be large compared with its volume. 4. Microscopes are needed to visualize cells. Because of their greater resolving power, electron microscopes allow observation of greater detail than can be seen with light microscopes. 5. Prokaryotic cell organization is characteristic of the domains Bacteria and Archaea. Prokaryotic cells lack internal compartments. 6. Prokaryotic cells each contain a nucleoid region and cytoplasm. Many also have cell walls, internal membranes, flagella, pili, and/or a cytoskeleton. 7. Eukaryotic cell organization is characteristic of cells in the domain Eukarya. Eukaryotic cells have many membrane-enclosed organelles, including a nucleus that contains DNA. 8. Organelles can be studied by microscopy or isolated by cell fractionation. 9. The nucleus is usually the largest organelle in a cell and contains most of the cell’s DNA. 10. The rough endoplasmic reticulum has attached ribosomes that synthesize proteins. The smooth endoplasmic reticulum lacks ribosomes and is associated with the synthesis of lipids. 11. The Golgi apparatus packages proteins inside vesicles and directs their transport. 12. Lysosomes contain digestive enzymes. 13. Mitochondria are enclosed by an outer membrane and an inner membrane that folds inward to form cristae. Mitochondria contain the proteins needed for cellular respiration and the generation of ATP. 14. Chloroplasts are enclosed by two membranes and contain an internal system of thylakoids organized as grana. Chloroplasts carry out photosynthesis. Other types of plastids include chromoplasts and leucoplasts. 15. Peroxisomes and glyoxysomes contain special enzymes and carry out specialized chemical reactions inside the cell. 16. Vacuoles are prominent in many plant cells and consist of a membrane-enclosed compartment that contains water and dissolved substances. By taking in water, vacuoles enlarge and provide the pressure needed to stretch the cell wall and provide structural support for the plant. 17. The cytoskeleton within the cytoplasm of eukaryotic cells provides shape, strength, and movement. It consists of three interacting types of protein fibers: microfilaments, which strengthen cellular structures and provide movement, intermediate filaments, which add strength to cell attachments in multicellular organisms, and microtubules, which are involved in the structure and function of cilia, flagella, and centrioles. 18. The cell wall of plants consists principally of cellulose. It is pierced by plasmodesmata that join the
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This note was uploaded on 04/09/2008 for the course BIO 140 taught by Professor Morvaridsoltani-bejnood during the Spring '08 term at University of Tennessee.

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E2-Study Questions - Chapter 4: Cells: The Working Units of...

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