Eukaryotes and Prokaryotes - Similarities and Differences

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Objective

SWBAT understand and compare and contrast the differences between eukaryotic and prokaryotic cells.

Big Idea

An interactive lesson that looks at the differences and similarities of the two giants of the cellular world.

Engage

5 minutes

In the first 5 minutes of class students read an article that discusses about the benefit of a "wimpy" handshake.  This lesson follows a lesson that introduces students to prokaryotes and its most famous example, bacteria.  

The rationale for using this article, besides its interesting topic (rate of bacteria transfer depending on type of handshake), is that it connects the previous lesson to today's lesson. In addition, it's an article that everyone can relate to since handshaking is a daily occurrence for most people.

Prior to having students read the article I give them a text dependent focus question.  The focus questions directs students to the author's purpose for writing the article.

Possible focus questions can be:  

1)  According to the author, why is there an upside to a "wimpy" handshake?

2)  What is the claim the author is stating? What is the author’s evidence to support the claim?(RL.6.1, RL.6.2)

After a quick share out I inform students that today we will be delving deeper into our study of cells, including for the first time exploring eukaryotic cells. 

Explore

20 minutes

During this part of the lesson students will explore the characteristics of eukaryotic cells and prokaryotic cells through a microscope lab. (SP3 - Planning and Carrying out Investigations)

The Microscope Lab is a three part lab where students will observe both eukaryotic cells (animal and plant cells) and prokaryotic cells.  

Since I haven't covered organelles, students are not responsible for labeling.  I will refer back to these sketches in the next lesson where I will introduce cell organelles.

  1. In Part A students observe plant cells by preparing a wet-mount slide of both an Elodea leaf and Onion.  Students are instructed to view slide under both low-power and high-power and draw observations.  

Elodea Cell

Onion Cell

Instructions on how to prepare a wet-mount slide:

 

  1. In Part B students observe animal cells by viewing both prepared animal tissue slides and wet-mount cheek cells.  Students are instructed to view both slides under low-power and sketch their observations.
  2. In Part C students observe bacterial cells under the microscope and sketch their observations.

 

The video below can be shown to students if this is their first time preparing a wet-mount slide. (SL.8.5)

Explain

10 minutes

In this part of the lesson students take Cornell Notes on the Two Types of Cells presentation that introduces students to eukaryotes and prokaryotes.  Secondly, this presentation introduces students to the nucleus, which is the distinguishing factor between both type of cells, and an organelle that will be the focus of many of the upcoming lessons.

The rationale for taking Cornell notes is that this note-taking system allows students to interact with notes by creating questions that clarify meanings, reveal relationships, establish continuity, and strengthen memory.  In addition students are required to write a summary or answer a teacher given essential question.  At the end of a unit  completed notes are great tool for studying for unit tests.

In addition to the powerpoint presentation, this Learners TV website is a great interactive site that allows students to explore prokaryotic and eukaryotic cells in greater depth (SL.8.5).  It is also a site that you can come back to and revisit once you have covered organelles, since it has a feature where you can construct cells.

Elaborate

10 minutes

In this section of the lesson students visit either CK-12 (1) Prokaryotic and Eukaryotic Cells or CK-12 (2) Prokaryotic and Eukaryotic Cells (SL.8.5).  Both sites are very similar in terms of content but with different videos, I provide both so you can select according to your preference. 

During this section, students do further reading on the eukaryotes and prokaryotes and watch a video that accompanies the reading.  After completing this task, students complete a post-read which helps them to organize information and supports their thinking in comparing and contrasting eukaryotic cells and prokaryotic cells. Comparing and contrasting is a more rigorous thinking task, because unlike listing characteristics or writing definitions, comparing and contrasting requires students to analyze individual characteristics to select like and unlike aspects between the two cell types.

Evaluate

5 minutes

To assess learning objective students complete Double Bubble map using the information gathered from lesson.  Students are to compare and contrast eukaryotes and prokaryotes using words such as unicellular, multicellular, membrane bound organelles, nucleus, bacteria, animal cell and plant cell.

Teacher Note:  I introduce the use of a double bubble map by modeling its use and by connecting it with the use of a Venn Diagram which most students are familiar with.

Things to compare and contrast with a Double Bubble Map:

1.  Sports ( Basketball vs Baseball)

2.  Movies (Toy Story 1 v Toy Story 2)

3.  Animals (Dogs vs Cats)