Cells

Lesson 3.1

Introduction to Cells

3.1.2 Types of cells

Since all living organisms are composed of cells, and variety occurs in types of living organisms, so too variety exists for types of cells. The cell that is the single-celled organism, Giardia, looks different from the single celled organism, Leptospirillum. These cells, in turn, look different from those that make up a multi-celled organism, such as fungi, plants, and animals. Cells within these multi-celled organisms will vary as well.

Based on physical structure, scientists have grouped cells into two categories: prokaryotic and eukaryotic. As a result of this, organisms can also be categorized as prokaryotes or eukaryotes, not both. There are many examples of these organism types living together in nature. For example, the human intestine houses prokaryotes, but a human is a eukaryote.

Each cell type is capable of carrying out the basic characteristic associated with life. They obtain energy, use materials, respond to their environment, reproduce, evolve over time, grow and develop, possess a genetic code, and are able to maintain a stable internal environment. Structurally, however, significant differences exist.

Prokaryotes and Eukaryotes video activity

1. View the video clip on Prokaryotes and Eukaryotes 
2. Complete the Prokaryotes and Eukaryotes worksheet.

Quick quiz

1.        Briefly describe what a cell is.

2.        State the three parts of the cell theory.

3.        List the two categories of cell types.

 Introductory Activity : Cell observations and groupings

1. Write your observations for each of the Cell Set photographs provided in Figure 3.1.1 below.
2. Compare Cell set A with Cell set E. How are they similar? How are they different?
3. Compare Cell set C with Cell set D. How are they similar? How are they different?
4. Based on your observations, which cell set would be most similar to Cell set B? Explain your answer.
5. Based on your observations, which cell set would be least similar to Cell set B? Explain your answer.
6. Share your work as directed by your instructor.