Lesson 1.2 Introduction to the chapter

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Introduction to the lesson

In this lesson we will begin to work in detail through the chapter. This lesson provides necessary background as it works through how people came to realize that all living things are composed of cells (the cell theory) and explains why we need cells. This basic understanding of the function of cells will be a good foundation as you go on in the next lessons to explore cell structure in more detail.


Read the section “Thinking outside the box” in your text book (p.2).

Thinking it through

  • What are prokaryotic cells and eukaryotic cells?
  • What is Darwin’s theory of evolution?
  • What is different in Lynn Margulis’ theory?
  • How do you personally respond to this suggestion of Lynn Margulis?
  • OPTIONAL RESEARCH: Find out more about Lynn Margulis and her theory.

Cell theory

Read the section under the "Thinking out of the box" section in your text book (p.2).

Learning Activity 1

Answer the following questions in your notebook.

  1. Write down the cell theory.
  2. What do you think are the implications of this theory?

Why cells?

Read the section under the heading “Why Cells?” in your text book (p.3).

Learning Activity 2

Answer the following questions in your exercise book.

  1. What are the functions of a cell?
  2. How are these functions performed?
  3. Why is the cell membrane important?
  4. What about the cell membrane allows it to perform its function?
  5. In your own words, explain the importance of the cell membrane being partially permeable. Why should the membrane allow certain substances in or out of the cell? Why should the membrane stop certain substances from moving in or out of the cell?
  6. List the three ways substances can move across the membrane. Give a brief description of each (You should recall this from IG / O levels).

Definitions and review


Define the following words in your notebook.

  1. Cell
  2. Cell theory
  3. Partially permeable
  4. Freely permeable
  5. Endosymbiosis


Start a mindmap of the chapter. You will create this mindmap one section at a time at the end of each lesson. By the end of the chapter you should have the entire chapter summarized in your mindmap. Make sure that you have all the important information on your mindmap but don't clutter it with unnecessary information -- it should be very brief (really just to remind you of the basic facts) but comprehensive. To give you an idea, here is an example of what a completed mindmap of chapter one could look like. The purpose of this mindmap is to help you learn and remember the work so find a style that suits you best. A mindmap is useful because it can display a lot of information on one page and show the connections between different topics and concepts. However, if you really struggle to work with a mindmap, be creative in finding another method of summarizing all your work in a concise and useful manner for later use. Add this first section to your mindmap/alternative summary.