Bio 108 Chapters 3 & 4

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Worksheet 2

1. a) Define a cell.  b) What is a unicellular organism? c) Can a cell be multicellular? a) Cell: Smallest unit that displays the properties of life; always contains cytoplasm surrounded by a plasma membrane. b) Unicellular Organism: An organism that consists of only one cell, unlike a multicellular organism that consists of multiple cells. c) No single cell is multicellular; however, it has been noted that a cell can evolve and become multicellular. 2. a) What is a difference between prokaryotic and eukaryotic cells? b) What is one significant similarity? d) Prokaryotic cells are a type of cell that lacks a membrane-bounded nucleus and organelles. Eukaryotic cells are a type of cell that has a membrane-bounded nucleus and membranous organelles. e) The similarities between the two cells are that both are enclosed with plasma membranes, contain ribosomes, have DNA, and are filled with cytoplasm. 3. Which type of microscopy uses a stream of electrons to produce magnified images? * Transmission Electron Microscope

4. Would you find proteins inside cells or cells inside proteins? (Choose one answer.) * Proteins are found inside the cell, because proteins are a macromolecule. 5. Which types of molecules (a) can cross the cell membrane freely and which (b) need direct assistance? f) Small, lipid-soluble molecules; such as oxygen and carbon dioxide can cross the cell membrane freely. g) Glucose, sodium ions and chloride ions need help to get through the cell membrane. 6.  Explain the basic organization (main components) of a plasma membrane. Include at least 4 distinct parts in your description. * The plasma membrane is a phospholipid bilayer with attached or embedded proteins. A phospholipid molecule has a polar hear and nonpolar tails. Carbohydrate chains are attached to the outside surface and cytoskeleton filaments are attached to the inside surface. 7....
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