Reading DNA - Translation

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Objective

SWBAT describe flow of genetic information from DNA to protein.

Big Idea

Students complete introduction to central dogma.

NGSS

1 minutes

This lesson build 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

To engage students in this lesson I show The Brilliance of Bioluminescence, a TED-Ed video. 

 

The reason I show them this video is that in order for organisms to possess bioluminescence they must have the DNA to be able to produce the proteins luciferase and luciferin.  This is a high interest (very cool) real world application and that brings meaning and value to the learning of DNA genetic information.

As students watch the video they answer the following questions:

1.  The production and emission of light by living organisms is referred to as...

a.  Phosphorescence

b.  Chemiluminescence

c.  Flurescence

d.  Bioluminescence

 

2.  What is the name for the fleshy growth on the anglerfish that contains bioluminescent bacteria and serves as a lure to attract prey?

a.  Blood pouch

b. Esca

c.  Phaskolos pouch

d.  Marsupium

 

3.  The railroad worm, Phrixothrix hirtus, can illuminate its body in two colors.  What are they?

a.  Yellow and green

b.  Red and blue

c.  Blue and green

d.  Red and green

 

4.  The deep sea shrimp, Acanthephyra purpurea, spews a bioluminescent cloud when it feels threatened. What purpose does this cloud serve?

a.  It frightens potential predators

b. It attracts the predators of its predators

c.  All of the above

d. None of the above

 

5.  Which of the following is not a component of the bioluminescent reaction in a firefly?

a.  A lucifer

b.  A luciferin 

c.  A luciferase

d.  Oxygen

Explore

25 minutes

In this section of lesson students explore translation by completing part 2 of the Reading DNA activity from Learn.Genetics. In this activity, students use a model to learn about translation and see the relationship between DNA structure and this process. (SP2 Developing and Using Models/CCC Structure and Function).

Learning Objectives

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

• 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. 

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:  This lesson is the second part of 2-day lesson; the topic of this lesson is mRNA translation.

I have attached below two videos of students completing activity where they are analyzing their mRNA sequence to determine Amino Acid sequence.  Students use provided Amino Acid table to determine which colored circle to select to place on their models.  As can be seen on video I project table on screen since paper copies are not in color. 

Explain

10 minutes

In this section of lesson I conduct an interactive demonstration of DNA transcription/translation from Learn.Genetics.

Transcription and translation

After the demonstration I have students complete a short reading, Translation of RNA to Protein, by cK-12.  Students answer the following questions as they complete reading:

  1. What is translation?
  2. What is a codon?
  3. What is a stop codon?
  4. What would happen if the stop codon was mutated to encode for another amino acid?
  5. Given the DNA sequence, ATGTTAGCCGTATGC, what is the mRNA sequence? What is the amino acid sequence?

Elaborate

10 minutes

In this section of lesson students complete STEP 2 and STEP 3 from the Say it with DNA activity we started in Day 1 of lesson.

STEP 2: Figure out the tRNA triplets (codons) that would fit the mRNA triplets (letter by letter).

STEP 3: Look up each tRNA codon in the tRNA Dictionary (below), and find the corresponding symbol and amino acid abbreviation for that codon. Record that one-letter symbol (and its amino acid) below each codon. "Spc" = "space". If you have done this correctly, the symbols should spell out a meaningful message in English.

Teacher Note:  Each student received a different DNA message sequence to decode in day 1 of the lesson.

Evaluate

5 minutes

In this section of lesson students complete Translation Worksheet which they began in day 1 of this lesson.  Prior to this lesson students have completed:

1.  Complimentary Strand of DNA

2.  mRNA (Transcription)

In this lesson students are required to complete:

1.  tRNA

2.  Amino Acid Sequence