McDougal Littell Science Cells and Heredity 

Table of Contents
Page 34 (continued)

1.3 Different cells perform various functions.

  • The single cell of a unicellular organism does all that is necessary for the organism to survive.
  • A multicellular organism is a community of specialized cells.
  • Scientific models make it easier to understand cells.


The tarsier has many levels of organization in its body.

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Reviewing Vocabulary

1–5. Use a vocabulary term to identify each numbered part of this plant cell.


In one or two sentences, describe how the terms in each of the following pairs are related. Underline each term in your answer.

  1. 6. unicellular, multicellular
  2. 7. cell, organelle
  3. 8. prokaryotic cell, eukaryotic cell
  4. 9. tissue, organ
Reviewing Key Concepts

Multiple Choice Choose the letter of the best answer.

  1. 10. Which statement about cells is part of the cell theory?
    1. a. Cells are found in most living things.
    2. b. Cells with cell walls do not have cell membranes.
    3. c. All cells capture energy from sunlight.
    4. d. Cells come only from other living cells.
  2. 11. What structure does a plant cell have that is not found in an animal cell and that allows a plant cell to capture energy from the Sun?
    1. a. cell wall
    2. b. chloroplast
    3. c. mitochondrion
    4. d. central vacuole
  3. 12. Which technology was important to the development of the cell theory?
    1. a. computer
    2. b. scientific model
    3. c. microscope
    4. d. refrigeration
  4. 13. Organisms can be divided into domains on the basis of the characteristics of their cells. What are these domains?
    1. a. Archaea, Bacteria, and Eukarya
    2. b. prokaryotes and eukaryotes
    3. c. plants, animals, and bacteria
    4. d. unicellular and multicellular
  5. 14. A complex multicellular organism has different levels of organization. What is the order of these levels?
    1. a. cell membrane, cytoplasm, nucleus
    2. b. tissues, organs, organ systems
    3. c. tissues, organs, specialized cells
    4. d. cell membrane, organelles, nucleus
  6. 15. What is the function of the genetic material in a cell?
    1. a. provides transport of materials from the nucleus to the cell membrane
    2. b. breaks down materials brought into the cell
    3. c. provides information a cell needs to function and grow
    4. d. controls what comes into a cell and what goes out

Short Answer Write a short answer to each question.

  1. 16. What are four characteristics common to all living things?
  2. 17. What are three needs common to all living things?
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Thinking Critically

Questions 18–20 refer to polar bears and their cells as examples of animals and animal cells.

  1. 18. PREDICT Some polar bears go through long periods of sleep during the cold winter months. In what two ways might their fat cells help the bears survive during these periods?
  2. 19. PROVIDE EXAMPLES Animals do not get energy directly from the Sun as plants do. Give one or two examples of body systems in a polar bear that help it obtain and process food.
  3. 20. COMPARE AND CONTRAST Consider the fat cells in a polar bear and compare them with the single body cell of a bacterium. How are the cells alike, and how are they different?
  4. 21. CONNECT The cell theory applies to all organisms, including you. State the three parts of the cell theory and describe briefly how they relate to you.
  5. 22. ANALYZE Louis Pasteur designed the swannecked flask to use in his experiments. In one experiment, he used two sealed flasks of nutrient broth. One flask he heated; the other he left untouched. Bacteria grew in the untouched flask. Nothing grew in the flask that had been heated, or sterilized. How did this experiment help disprove the theory of spontaneous generation?
  6. 23. PREDICT What would happen if the neck of the sterilized swan-necked flask were broken?
  7. 24. IDENTIFY CAUSE Why does pasteurized milk eventually spoil?
  8. 25. COMPARE AND CONTRAST A plant cell has a number of structures and organelles that an animal cell does not. Copy the table below and place a check in the appropriate box of each row. The first two are done for you.
     Animal CellPlant Cell
    Cell wall 
    Cell membrane
    Central vacuole  

the BIG idea

  1. 26. CLASSIFY Look again at the photograph on pages 6–7. Can you identify any of the structures shown? Can you identify the type of microscope used to make the photograph? How do you know?
  2. 27. CONNECT What are three ways that an understanding of cells has changed the way people live? Hint: Think about Pasteur and his work.


If you are doing a unit project, make a folder for your project. Include in your folder a list of the resources you will need, the date on which the project is due, and a schedule to track your progress. Begin gathering data.