Lesson Plan #:AELP-GET0001

How Cells Duplicate and Why
Where Something Can Go Wrong

An Educator's Reference Desk Lesson Plan

Submitted by: Judy A. Grunke, Weiser Junior High, Weiser, Idaho
Endorsed by: These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center's Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.

Date: May 1994

Grade Level(s): 7

Subject(s):

OVERVIEW: Cells are the basic unit of function and structure in living things. After students have learned cell parts and organization, they are introduced to cell division. Understanding the role of deoxyribonucleic acid (DNA), and how and why it must replicate, is essential to comprehending how our genetic patterns are transmitted to new cells. Constructing a three-dimensional model of the DNA molecule enhances the students' discernment.

PURPOSE: Genes are the small heredity units on chromosomes and are made of DNA molecules. Before a cell divides, the DNA must replicate so that the two new cells will each have the organism's genetic code. If foreign materials invade the cell while the DNA is duplicating, they may be incorporated into the molecule. If these miscoded cells are not killed by the body's own defense systems, they will multiply and could take over, disrupting the cell's normal activities or dividing rapidly and erratically, crowding out the normal cells. It is important to understand the construction of the DNA molecules; how and why they divide; how good nutrition and personal habits can help maintain the genetic code.

OBJECTIVE(s):

1. The learner will be able to define pertinent vocabulary.
2. The learner will be able to describe the DNA molecule, its construction, how it replicates.
3. The learner will be able to discuss why good nutrition is essential for proper DNA duplication.
4. The learner will be able to explain how, when, a carcinogen may be incorporated into the DNA molecule.
5. The learner will demonstrate his/her understanding of the DNA molecule by constructing one from chenille pieces.

RESOURCES/MATERIALS:

Provided: textbook, paper, pencils, (colored pencils are excellent) Needed: Film: "The Intricate Cell", American Cancer Society, Boise, ID For Lab: 6 pieces chenille per student (2 the same color, 1 each of 4 different colors) wire cutters or sharp scissors

ACTIVITIES AND PROCEDURES:

SET Models of a cell undergoing mitosis. A model of a DNA molecule.

INSTRUCTIONAL INPUT VOCABULARY: deoxyribonucleic acid, DNA, gene, chromosome, replicate, mitosis, nutrients, carcinogen

REVIEW: Nutrients, food containing them. Protein contains nitrogen, an essential ingredient in the DNA molecule. Mitosis--interphase, when the DNA replicates.

DISCUSS: How DNA molecules are constructed; when and how the DNA molecule makes a copy.

FILM: "The Intricate Cell" Observe cells undergoing mitosis and the construction of DNA molecules. Discuss the causes of 80% of cancers--industrial pollutants, overexposure to the sun, cigarette smoke. Discern how and when cancer-causing agents can disrupt DNA's replication.

GUIDED PRACTICE TEXTBOOK: vocabulary and study questions CLASS NOTES LAB: Construct a DNA molecule

INDEPENDENT PRACTICE Quiz, Text

TYING IT ALL TOGETHER: Deoxyribonucleic acid (DNA) is the molecule which contains our genetic codes. The DNA must copy itself before the cell divides so the daughter cells will get the code. The cell has to have the proper nutrients in the right amounts so that the DNA can replicate. If carcinogens are in the cells when the DNA is duplicating, they may be incorporated into the DNA molecule. Cigarette smoke contains known cancer-causing materials. We have control over 80% of known carcinogens.