Biology

Lesson 2 -- How are DNA, RNA and amino acids like a language?

Lesson Plan

 

State Standards:

3.2 Describe the basic process of DNA replication and how it relates to the transmission and conservation of the genetic code. Explain the basic processes of transcription and translation, and how they result in the expression of genes. Distinguish among the end products of replication, transcription, and translation.

Essential Question:

How is DNA, with only four "letters", able to express genes as proteins?

dna_replication_split_madprime

Lesson Question:

How are DNA, RNA and amino acids like a language?

Introduction:

In this lesson you will learn how the information contained in the genetic code, DNA, is able to be changed into other types of information that is used to make proteins. Proteins are what make an organism look and function in their own unique way. You will learn how language, the alphabet and grammar can be used as an analogy in understanding the process of protein synthesis. You will make up your own analogy and describe how it can be used to explain the process of gene to protein.

Task:

In this investigation you will think about what you know about the alphabet, words, sentences and grammar to help you understand how the information contained in your genes is expressed. For homework you will explore, individually, some videos about protein synthesis and fill out a table comparing the English language to protein synthesis. In a group of three, you will develop your own analogy for what protein synthesis. You will use Glogster in your group to illustrate your analogy. Then you will present your Glogster to the class. This task will help you in understanding the many steps of protein synthesis.

Lesson Experiences:


Day 1


Complete the following steps as HOMEWORK before we start the Day 2.

  1. In your GoogleDocs you will find a blank table (see table below). Fill in the column labeled "English." (5 minutes)
  2. Watch the videos on transcription and translation. You will notice there are two sets of videos. The second set contains more advanced information. You must at least watch the basics videos, you may wish to watch both sets. (20 minutes)
  3. After watching the videos complete the table and share it with your teacher through GoogleDocs. (10 minutes)
  4. Try an online program for building a protein.

Before watching the videos below, fill in the column labeled "English" in your notes or in a GoogleDoc. After watching the videos fill in the remainder of the table and email or share the table with me.

English

DNA

mRNA

Protein

Number of letters in “alphabet”?

What signals a start of a “sentence”?

What signals the end of a “sentence”?

Minimum number of letters in a word?

DNA Transcription (Basic)

Youtube:  DNA Transcription (Basic)

Transcription (Advanced)

YouTube:  DNA Transcription (Advanced)

Translation (Basic)

YouTube:  mRNA Translation (Basic)

Translation (Advanced)

YouTube:  mRNA Translation (Advanced)

Now that you have completed the table and watched the videos, try building a protein using the site below.


Build a Protein

Day 2

In class discussion: (20 minutes)

    1. How does language, with its use of letters, grammar, words and sentences, convey information?
    2. How does the cell use a chemical language to convey information?
    3. Compare tables.
    4. How is gene expression like a Harry Potter movie?

In groups of three, brainstorm ideas of an analogy of your own on how gene expression (gene to protein) works. (20 minutes)

Homework: In GoogleDocs, work with your group to fine tune your analogy.


Day 3

Today you will work with group on the computer and create a Glogster expressing your analogy. Focus on the content more than the visual. You will see my example of a Glogster for "How a Harry Potter movie is like protein synthesis" below. (45 minutes)

Glogster

Glogster

Homework, prepare to explain your Glogster to the class. Presentation should be ten minutes. Use the rubric below to check your work.

Day 4

  1. Present your Glogster to the class.
  2. Discuss what you've learned.

Conclusion:

In this lesson you learned the process of protein synthesis through the use of analogies. You should be able to explain the process. You also learned how to use Glogster as a way to organize and present information. You may now wish to learn about how scientists discovered the sequence of steps and the molecules of the process.

Assessments:

 

Strong
4

Good
3

Adequate
2

Inadequate
1

Percent

Contribution to group

Each person contributed equally to creating the analogy, making the Glogster and had equal speaking time in the presentation. Every participant understood every part of the process. No one dominated the group.

Each person contributed nearly equally.

One or two people dominated the group. The contribution was not equal.

The group did not work well together. Only one person worked on the assignment.

20

Analogy Content

The analogy logically explains the process of protein synthesis. Each step is explained so that knowledge of the step in well understood.

The analogy logically explains the process but each step is not well explained.

The analogy is not a good fit for protein synthesis. Few steps are explained.

The analogy is not a good fit for protein synthesis and none of the steps are explained.

40

Glogster

The Glogster is well organized and creative.

The Glogster needs better organization and is fairly creative.

The Glogster is not well organized but shows some creativity.

The Glogster is not well organized and does not show effort or creativity.

20

Presentation

The presentation is well organized and fits into the time frame.

The presentation shows some organization. It was a little too long or too short.

The presentation shows little organization. It was a too long or too short.

The presentation was not well organized and was more than five minutes too long or too short.

20

Score

 

Resources:

Glogster
YouTube
U of Utah: Gene to Protein Site
Prezi on Protein Synthesis This Prezi contains great back ground information. It is advanced for middle school but could be copied and edited to suite your needs. It has a good overview of the history of understanding the role of DNA and RNA.

Materials -- Paper, pencil, access to GoogleDocs, access to Glogster, Gmail account, Computers with Internet access, at home and in class


Biology: Concepts & Connections, 5/E Media Update. Neil A. Campbell, Jane B. Reece, Martha R. Taylor, Eric J. Simon
ISBN: 0-32-151244-8

Teacher Notes:
One teacher can teach this lesson. The use of a technology person may be helpful.

On the first day of the unit, make sure everyone has their GoogleDocs account and understands how to share documents. Also explain how Glogster works. Explain homework assignment which should be completed before the start of the lesson.

Other Resources:

Biology 1 Action Plan Notes

The notes below are from my action plan. This lesson plan uses the 7E in a more formal way than the lesson above. It also spends more time on each step. I included it as a resource/reference.
Elicit :
How do you know when a new sentence starts or stops when reading text?

If you traveled to a country that spoke a different language how would ask for information in the native language?
Engage
Engage
Objective: to understand the processes of transcription and translation.

Pick any three letters from the alphabet, try to make as many words as you can from the three letters.
Write on board “My name is __. I live in Boston. I am a teacher/student.” Have students copy the statement. Ask what this process is called when we copy words as they are written. (transcribe)
Now ask students to change the language of the sentences but keep the meaning. What is this process called? (translation)

Explore 1
Objective: DNA is converted or transcribed into mRNA by pairing the nucleotides A to U , T to A, C to G and G to C.

Have students practice converting the DNA sequence into the mRNA sequence.
This process of converting is called “Transcription.”
Remember that the “T” of DNA becomes a “U” in RNA.
Rather than identical transcription, mRNA is complementary.

Explain 1
Objective: Use language and grammar as an analogy for understanding transcription.

Like a student writing down notes from a board, DNA is transcribed into mRNA.
Relate the idea that our language, with 26 letters, makes all the words in a dictionary. DNA, with four letters or nucleotides, makes all the words needed for mRNA to carry its information.
Punctuation (capital letters and periods) lets us know when a sentence starts and stops.
DNA has “punctuation” letting the enzymes know when a gene starts and stops.
Big Idea : DNA is transcribed into mRNA, although the letters are complimentary rather than identical.

Explore 2
Objective: Three letter Codons = One amino acid

How many letters are needed to make 20 different words? (limit the letters to A, C, G, U)
Have students create their own table of three nucleotides, called codons.
Show them the table that identifies the amino acid for each codon.
Some codons act as “punctuation”
Many amino acids have more than one codon, these are called synonyms, just like when different words with the same meaning are called synonyms.

Explore 3
Objective: learn how three mRNA nucleotides code for one amino acid. Learn the role of the ribosomes and tRNA.

Model the translation of mRNA (3 nucleotides) into a sequence of amino acids by using a “print shop” called a ribosome and helpers called tRNA.

Explain 2 & 3
Have students read the section on protein synthesis out loud in class. Explain areas of difficulty.

Define transcription and translation as they relate to protein synthesis.

Identify other terms such as codons, mRNA, ribosome, tRNA, anticodon (part of tRNA), amino acid and protein.

Like a person translating a sentence into another language, mRNA is translated into a sequence of amino acids that make a protein.
Three nucleotides code for only one amino acid (amino acids can have more than one codon)

mRNA also has “punctuation” telling the tRNA where to start and stop translating mRNA into the amino acids that build the protein.
Ribosomes act as a little printing presses where the amino acids are assembled into proteins.

tRNA brings the correct amino acid to the ribosome by matching up its three nucleotide anticodon to the mRNA.


Explore 4
Objective: to learn all the steps of protein synthesis.

Put it all together: Model both the transcription of DNA to mRNA and the translation of mRNA into a sequence of amino acids that make the correct protein. Make sure that the final protein is correct (evaluate)

Elaborate
Give the students a sequence of DNA that codes for a protein.
Have the class divide up the “roles” of protein synthesis and act out the process. Once they succeed, have the students switch roles.

Evaluate
Check that the protein is correct. At the end, have the students explain the process in writing as a test.
They can use the language/grammar analogy as means to explain the process.

Extend
Have students research the different structure levels of proteins. (primary, secondary, tertiary, quaternary)
Have the students explain how a mutation in the DNA sequence could cause a change in the protein function.
Have students research a genetic disease (such as cystic fibrosis) that causes a change in a protein.
Have student research how scientists discovered the process and molecules involved in protein synthesis.

 

Image credit: "DNA replication split" by Madprime, from Wikimedia Commons.