Reading DNA - Transcription

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Objective

SWBAT apply base pairing rules in DNA transcription.

Big Idea

Students begin to explore central dogma of biology.

NGSS

1 minutes

This lesson builds on the foundational knowledge that students will need to know in order to address the following inheritance and variation standards:

MS-LS3-1. Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

MS-LS3-2. Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation. 

Knowledge of the structure and as a result the function (transcription, translation) of DNA is required knowledge to understand both effects of genetic mutations, asexual, and sexual reproduction. 

Engage

10 minutes

In this section of lesson I have students complete a Hieroglyphic Worksheet.  The reason I choose this activity is that students need to translate/decode their name from English to hieroglyphics.  The decoding of DNA is similar to this multi-step process.  Another reason I choose this activity is that it connects to what my students are studying in World History.

               

Explore

25 minutes

In this section of lesson students explore DNA transcription by  completing "Making a Copy of DNA-Transcription" from the Reading DNA activity courtesy of Learn.Genetics. In this activity students use a model to learn about transcription and see the relationship between DNA structure and this process. (SP2- Developing and Using Models/CCC - Structure and Function).

Learning Objectives (after 2 day lesson)

• Students will understand that information within the DNA molecule is divided into segments called genes. (Day 1)

• Students will learn that each gene contains the instructions for assembling a unique protein that performs a specialized function in the cell. (Day 2)

• Students will be able to summarize the two-step process of transcription and translation by which the information in a gene is used to construct a protein. (Day 2) (CCC- Structure and FUnction

Prior Knowledge Needed:

A basic knowledge of DNA structure and function.

Key Concepts:

Gene, transcription, translation, mRNA, protein, Universal Genetic Code

Materials:

Black licorice sticks, colored marshmallows, toothpicks, colored circle cut- outs, tape, scissors, and edible models of DNA previously built for the activity Have Your DNA and Eat It Too


Teacher Note:  Reading DNA contains a Teacher Guide with background information on DNA transcription and translation.  I split this activity into two lessons because from prior experience I have discovered that covering both transcription and translation is too much information for 7th grade students.  As a result in Day 1 we cover transcription and on Day 2 Translation.

Explain

10 minutes

I explain the steps involved in going from DNA to protein by completing Cell Transcription and Translation interactive demonstration on the SmartBoard. 

After demonstration students visit cK-12 to complete a quick reading on Transcription of DNA to RNA.  As students complete reading they answer the following questions:

  1. What is the final product of transcription?
  2. How does the genetic code in the DNA get passed on to the mRNA?
  3. What will be the mRNA sequence transcribed from a TTAAACGGCCTA template?

Elaborate

10 minutes

In this section of lesson the students elaborate on what they have learned by completing STEP 1 from the Say It With DNA Student Sheet.

Having studied the process by which DNA directs the synthesis of proteins, you should be ready to decode some DNA "secret" messages. To do this, you must follow the procedure of protein synthesis as this is taking place right now in your cells; no short cuts! Practice these steps by following and finishing the partially solved message below.

STEP 1: "Build" the mRNA molecule, matching the RNA nucleotides to the DNA nucleotides properly, letter by letter. (For purposes of simplicity, it will be assumed that this mRNA is bacterial; there are no introns to cut out!)

Teacher Note:  Students will complete Step 2 and Step 3 in day 2 of lesson since these steps require knowledge of translation.

Evaluate

5 minutes

In this section of lesson I have students complete a Transcription Worksheet.  The purpose of this activity is to assess student comprehension of DNA transcription.  The formation of the correct mRNA sequence is needed for correct translation of protein which is the topic of next lesson.