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Unformatted text preview: 1 C HAPTER 1 INTRODUCTION TO CELLS Unity and Diversity of Cells 1-1 The smallest unit of life is a(n) (a) DNA molecule. (b) cell. (c) organelle. (d) virus. (e) protein. 1-2 For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; each word or phrase should be used only once. Cells can be very diverse: superficially, they come in various sizes, ranging from bacterial cells such as Lactobacillus, which is a few __________________ in length, to larger cells such as a frogs egg, which has a diameter of about one __________________. Despite the diversity, cells resemble each other to an astonishing degree in their chemistry. For example, the same twenty __________________ are used to make proteins. Similarly, the genetic information of all cells is stored in their __________________. Although __________________ contain the same type of molecules as cells, their inability to reproduce themselves by their own efforts means that they are not considered living matter. amino acids micrometer(s) viruses DNA millimeter(s) yeast fatty acids plants meter plasma membranes 1-3 Which of the following statements about the basic chemistry of cells is TRUE? (a) All cells contain exactly the same proteins. (b) All proteins are constructed from the same 22 amino acids. (c) The genetic instructions in all cells are stored in DNA. (d) All organisms contain the same genes. (e) All of the above ;B1;Garland;Science;Publishing; T 2 1-4 Which of the following statements is TRUE? (a) Mutations are always harmful to an organism. (b) Mutation is essential for evolution to occur. (c) Mutation is the only source of genetic differences between parents and offspring in plants and animals. (d) Mutation always leads to evolution. (e) Mutations always lead to evolutionary dead ends. Cells Under the Microscope 1-5 What unit of length would you generally use to give the measurements of a typical human cell? (a) Centimeters (b) Nanometers (c) Millimeters (d) Micrometers 1-6 A. What sets the limit on the size of structure that can be seen in a light microscope? B. Why are tissues usually cut into thin sections and stained before examination under a light microscope? 1-7 State whether you would use a phase-contrast light microscope , a fluorescence microscope , an electron microscope , or none of the above to do the following things: A. look at unstained living animal cells. B. look at ribosomes. C. look at an electron. D. look at a living cell expressing green fluorescent protein. E. do confocal microscopy. The Procaryotic Cell 1-8 Which of the following statements concerning procaryotes are TRUE?...
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- Spring '12