Crack the Code! Transcription and Translation Activity (Erina Galanukan)

Title: Crack the Code! Transcription and Translation Activity

Principle(s) Investigated:

Transcription and Translation

-Students will be introduced to the process of transcription and translation, and understand how the processes work together in order to make meaning of the instructions that DNA provides.

Mutations

-Students will be introduced to mutations, and how there are different kinds of mutations that have different effects.

Standards:

HS-LS1-1: Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS3-1: Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parent to offspring.

Materials:

"Crack the Code" Worksheet

-See photos for how to format the worksheet. To make part one simpler to complete, the code given can be grouped into threes, and the lines to write the transcribed code in can also be grouped similarly. The code-breaker should be present on the worksheet.

"Translator"

-The translator should be projected on the board, or otherwise placed somewhere that everyone can see. You can instruct students to move closer to the board if they cannot see it.

Pens/Pencils

Treat (Optional)

Spooky music (Optional)

Procedure:

The Activity

1. Explain to students that they will be attempting to "crack a code" while you pass out the worksheet. Students can work independently or in pairs. Have them keep the worksheet face down as you pass it out. Explain that they will be given a code, a code-breaker, and a translator to help them with their task.

2. Before they start, show them the "translator." Go through with them step-by-step how to use it, and clarify any questions the students have. This part is important; if the students do not know how to use the translator, they will not succeed with this activity.

3. Have students turn over their paper and start. Give them ample time to finish--wait for all students to finish before moving on to the explanation.

Student prior knowledge:

Students should know the structure and function of cell organelles. Students should also know the basic structure of DNA, and be familiar with the process of DNA Replication.

Explanation:

The Debrief and Explanation

1. Ask students what they got when they "cracked" the code.

2. Discuss the difference between part one (using the code-breaker) and part two (using the translator).

-Part one uses the code-breaker. This is analogous to transcription. The original code is simply being changed for the translator; it still has no meaning.

-Part two uses the translator. This is analogous to translation. The revised code is used in order to make meaning, and at this point we can understand what the code is trying to tell us.

-Transcription and translation make up the Central Dogma of molecular biology. Show a diagram of the Central Dogma (example in the photo section).

3. Discuss the effects of changing parts of the original code.

-Changing certain letters from the transcribed code: There are instances when mistakenly changing a letter during transcription will not have an effect, when it will have a beneficial effect, when it will have a neutral effect, and when it will have a detrimental effect. Discuss these instances by changing a letter from the code, and having students examine the change in the command.

-Adding or removing letters/chunks of letters: Examine the effects of adding or removing letters or chunks of letters with the students. Have them observe how the command changes, and whether it still makes sense.

Explain that mistakes during transcription lead to mutations. Some mutations are non-noticeable, some have a beneficial effect, some have a neutral effect, and some are detrimental.

Show photos of genetic disorders and diseases (examples in the photo section).

Questions & Answers:

Why is genetic variation important?

Genetic variation is important because too many of the same genes can lead to genetic disorders. Having the same or similar genes when mating is more likely to result in recessive combinations, which have a higher risk of genetic disorders. This is because when one has a homozygous dominant or heterozygous combination of alleles in their DNA, the dominant one is expressed and can "mask" mutations that the recessive allele may carry. However, when there is a combination of two recessive alleles (which, as stated previously, is more common in pairings of similar genetic makeup) this "masking" does not occur, and the mutation, which may be detrimental, will be expressed.

If mutations can be harmful, why do they exist?

This goes back to the first question--mutations lead to genetic variation, which is important in any species! Contrary to what may be perceived, many mutations are harmless. In humans, mutations are what lead to the variety of different eye colors, hair colors, height, and so on. Mutations can be neutral or even help the survival of a species--they are not always harmful. The majority of harmful genetic mutations in humans are non-viable, meaning that the zygote will not survive; it may be spontaneously aborted or die shortly after birth. Only a select few are viable, such as Down's Syndrome. There are microbiologic reasons as to why mutations exist as well, but they will not be discussed in depth in class.

Will all humans look the same someday?

There's no absolute answer to this--some believe that due to the increase of international relations, immigration, and globalization, there will be an increase in gene mixing, and that humans will begin to look more similar to each other in the future. However, genetic engineering is a growing field of study, and we are still learning about DNA and how genes interact with their environment. Someday we may even have the technology to be able to choose our progeny's physical traits. At this point in time, the possibilities are endless!

Applications to Everyday Life:

Genetic Disorders

Transcription and translation are important to know in order to understand genetic disorders. When mutations in gametic cells contain certain mutations, it can affect the production of essential proteins, which often render the zygote non-viable. It can also lead to genetic disorders such as Cri du chat or Down's Syndrome. For example, Cri du chat is caused by a deletion on chromosome 5.

Somatic (Acquired) Mutations

Some diseases, such as cancer, are not inherited, but rather acquired throughout one's lifetime. These are called somatic mutations, because they occur in somatic cells. These genes are not passed down to progeny, though it is generally accepted that one may be more susceptible to certain diseases if their parents had it. Cancer can be caused by mutations that affect proteins that normally control the growth of cells (oncogenes), ones that suppress tumors (tumor suppressor genes), or control stability (stability genes).

Variation of Traits

Though "mutation" may sound like a daunting term, many mutations are relatively harmless. They can contribute to a great variation of traits. Some traits may be favored or disfavored in certain populations, which may affect survival, but the mutation itself does not directly cause disorders or diseases. For example, the reason there is so much variation in hair color, eye color, and height in humans is because of the different mutations we have acquired, and are now part of our genetic makeup.

Photographs:

Translator

This sheet should be projected on the board where everyone can see. Words can be altered to create different "codes" for the students to crack.

Worksheet for students

The worksheet should have the Code-Breaker on it so students can complete Part One. As shown, you can split the code as well as the lines to transcribe and translate the code up into groups of three to make it easier for students to do, or to make it more challenging, you can simply provide them a code with no spaces and tell them that they must break it up into threes themselves.

Sickle Cell Anemia

Cancer

Transcription and Translation Diagrams

Simple diagram (central dogma)

Detailed diagram

Videos:

The activity itself is fairly straightforward once you have the worksheets, so I have included here videos that reviews transcription and translation.

This video highlights the main points of transcription and translations, with much more detail included.

This video showcases different types of genetic mutations in a technical way--the activity simply introduces mutations and therefore is not this technical, but the main ideas are the same.