Activity 3 What Is a Cell?

Write or sketch your responses in your science notebook: What do cells look like? What are cells made of? What do cells do? What is difference between unicellular and multicellular organisms? Give examples of each

Challenge What are the similarities and differences in cells from various living organisms?

View slides of various kinds of cells Draw 3-5 cells As you view the slides, think about the similarities and differences in the various types of cells. Identify the magnification power that you made your drawing under After students have completed Procedure Step 1, project Transparency 3.1, “Examples of Cells,” to prompt students’ further thinking about cells and cell characteristics. For more information on how to support students in this activity, and for descriptions of each type of cell they’ll be looking at, see your Teacher’s Edition.

What similarities & differences did you observe in all cells? Which cells were plant cells? What similarities did you notice in the plant cells? Which cells were animal cells? What similarities did you notice in them? What similarities & differences did you notice in the two bacteria cells What similarities & differences did you notice in the 3 protist cells? What difference did you notice between the bacteria & the protists?

Now organize information… Use what you have learned about cells to record the unique features of the cells of each group of organisms in the appropriate space. Record any common features between groups in the spaces created by overlaps. Analysis Question 4 is a Quick Check assessment to assess students’ developing understanding of the unique and shared characteristics of cells of organisms.

Based on the Venn diagram you created, what features are common to all cells? Based on your observations, can you conclude for certain which cells do and do not have a nucleus?

CASE STUDY: TUBERCULOSIS Read the case study in your book beginning on p. 177 Get some sticky notes and use the READ…THINK…TAKE NOTE strategy (see next slide for guidelines) After reading the passage…discuss your notes with your partner

For more information on using this literacy strategy with your students see your Teacher’s Edition for this Activity and see Teacher Resources III: Literacy. These guidelines can also be found on Literacy Transparency 3, “Read, Think, and Take Note.”

TUBERCULOSIS Complete the disease information case study sheet How are antibiotics and vaccines different? What are each used for?

ANTIBIOTICS medications that destroy or slow down the growth of bacteria.

VACCINE… substance used to stimulate the production of antibodies and provide immunity against one or several diseases prepared from the causative agent of a disease, its products, or a synthetic substitute treated to act as an antigen without inducing the disease.

One focus of TB treatment is ensuring that people who are being treated are being closely monitored by health care workers. Explain why this is important, citing evidence from the tuberculosis case study