Demonstrating the Understanding of Cellular Organelles

Summer Research Program for Science Teachers

George Wingate High School, Brooklyn

2000

Subject: Biology

Grade Level: 9^th-11^th

Time Allocation: Four 45-minute periods

This lesson plan was created to meet several instructional objectives in accordance to the New Science Standards while involving the students in the learning process. Consequently, students will be exposed to the structure and functions of cells through the use of a laboratory, an Internet activity, and cooperative learning. Students will demonstrate their understanding of cellular organelles by creating a model of a typical plant or animal cell. Students will be able relate the malfunctioning of some organelles to health problems such as Mitochondrial Toxicity.

Cooperative Learning Activity

Objectives: Students will be able to:

§ Distinguish the similarities and differences between Prokaryotic and Eukaryotic cells.

§ Demonstrate their understanding of the structures and functions of cell organelles.

§ Learn interpersonal skills as they share, compare, and discuss ideas with each other.

§ Observe a 3-Dimensional model of plant and animal cells.

Materials

Film on function and structures of cells

VCR and TV set

Pens, pencil and notebook

Activity Sheet

Procedure

1. Divide the class into groups of 4.

2. Instruct students to watch the video, take notes and make drawings of at least five organelles.

3. Give the groups at least 15 minutes to discuss and compare their notes.

4. Hand out the activity sheet and inform the groups that all members must contribute to the answering of the questions.

Activity Sheet for Cooperative Learning

Please write down the answers to the following questions as determined by all members of your group.

1. What are cells? [9-12 Content Standard C- The cell]

________________________________________________________________________

2. How would a cell be affected if its mitochondria became nonfunctional or damaged?

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

________________________________________________________________________

3. Why must the cell membrane be selective in its permeability?

________________________________________________________________________

4. Provide an explanation as to why a cell ultimately dies when its lysosomes are ruptured.

5. As a group, please rate the importance of 5 organelles and give a reason as to why each organelle is rated at that level in the box.

1⁰______________________________________________

2⁰______________________________________________

3⁰_______________________________________________

4⁰______________________________________________

5⁰______________________________________________

Laboratory Activity

Overview: A cell is the smallest unit that can carry out the life processes discussed in a previous lesson. Although all cells have certain characteristics in common, cells can vary in size, shape, and structure. In this activity, we will employ the use of a microscope and other scientific techniques to investigate and examine a variety of plant and animal cells. [9-12 Content Standard E- Understandings about science and technology]

Objectives: Students will be able to

§ Examine the structure of animal and plant cells

§ Identify similarities and differences in plant and animal cells

§ Apply the knowledge of the scientific method and scientific enquiry

§ Demonstrate the skills of preparing a wet mount and staining of cells

§ Analyze data and apply thinking skills on a well constructed lab report

Materials

Dropper, cover slips, tweezers, slides, microscope

Elodea, flat toothpicks, sheep’s blood, onion, lab book

Iodine solution, scalpel, blood staining reagents [Teaching Standard D- Make accessible science materials]

Procedure

1. Explain the activity to the students in previous lesson.

2. Ask students to divide their lab book into two sections.

3. As homework, they should rewrite the procedure for the activity on the left section of their lab book.

4. Remind students that the right section of the lab book should be used for their observation or questions.

5. Explain to students about the components of their lab report and discuss what each should entails:

Analysis and Conclusions of Lab Activity

1. How does the structure of cheek cells compare with the structure of onion epithelial cells? [Content Standard Unifying Concepts- Evidence and explanation]

2. Describe the physical characteristics and functions of the red blood cell.

3. How do the staining reagents change the appearance of the cells?

4. Describe the shape and the location of the chloroplasts in the elodea leaf.

5. In which cell did you see movement of the cytoplasm?

6. Draw and label a generalized structure of a plant cell and an animal cell. Under each diagram show the mathematical formula used to determine the total magnification of each cell.

7. The main function of red blood cells is to carry oxygen to the tissues. Later it was discovered that red blood cells do not have a mitochondria and derived their energy from anaerobic respiration. Explain why the absence of this organelle is to the benefit of the tissues and the body as a whole.

8. A detective, called to the scene of a crime, collected samples of tissues found nearby. How could the police forensic team determine whether these tissues were from a plant or an animal? Moreover, the detective had two suspects but only one of them committed the crime. Given that the victim had a piece of foreign tissue under her nails, what are the biotechnology techniques that could be used to identify the killer? [Teaching Standard B- Orchestrate scientific discourse]

Internet Activity

Objectives: Students will be able to

Observe a 3-dimensional plant and animal cell

Test their understanding of the structures and functions of organelles

Relate the malfunctions of organelles to health problems such as Mitochondrial Toxicity

Procedure

1. Each student will download the models of plant and animal cells at Http://www.cellsalive.com/cells/3dcells.

[Teaching Standard D- Make accessible science media]

2. Students will draw and label a plant or an animal cell and answer the multiple choice question at the above site for 20 minutes.

3. Students will read about Mitochondrial Toxicity and its correlation with HIV medications at http://www.aidsinfonet.org/.

4. For the remaining of the period, the class will discuss the disadvantages and advantages of HIV medications and come to a solution for the health problems of Mitochondrial Toxicity.

Extended Activity

Objectives: Students will be able to

Demonstrate their understanding of cell structures and functions by creating a model of a typical plant or animal cell.

Explain the steps taken in designing their individual model to the class

Relate the materials used to represent each organelle to the shape and function of the organelle.

Criticize and evaluate the work of other classmates. [Teaching Standard E- Structure and facilitate formal and informal discussion]

Procedure

Distribute to students a sheet with the following instruction:

Your task is to complete a 3D model of a plant or animal cell, naming, and describing the functions of each organelle. Along with the model, you must hand a paper describing the steps that you took in designing your cell and the reasons why certain materials were used.

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