Download From DNA to Protein

From DNA to Protein
Part of:
Inquiry Science with Dartmouth (a new program!)
Developed by: Jessica Day
Adapted from: Dear sixth grade forensic scientists
Overview
In this lesson students will become more familiar with the processes of transcription and
translation by performing these tasks with puzzle-like pieces that represent DNA, RNA, tRNA,
and amino acid molecules.
Science Standards (NH Science Curriculum Frameworks)
S:LS3:8:3:1 Recognize that hereditary information is contained in genes, which are located in the
chromosomes of each cell; and explain that inherited traits can be determined by either one or
many genes, and that a single gene can influence more than one trait, such as eye and hair color.
S:LS3:8:3:3 Explain how individual organisms with certain traits are more likely than others to
survive and have offspring.
S:SPS2:8:3.2 Know that different models can be used to represent the same thing; what kind of
model is used and how complex it should be depends on its purpose; and the usefulness of a
model is one of the instances in which intuition and creativity come into play in science,
mathematics and engineering.
Focus Question
How does the message found in DNA get interpreted into proteins?
Objectives
Through this lesson, students will be able to:
• Illustrate the pathway from DNA to protein (central dogma)
• Describe the process and steps of the pathway
Assessment
• Question on handout: “Illustrate and describe the central dogma”
• Observations: View students laying out the DNA to RNA to Protein pathway with puzzle
pieces, note if students comprehend the effect of a single nucleotide change.
• Wrap questions
Background
In this activity you will be given DNA nucleotides, RNA nucleotides, tRNAs, and amino acids.
You already know that the nucleotides are represented by the letters A, T, G, C, and U. Amino
acids are also often represented by a single letter, so on each of your amino acids there is a
single letter. Your tRNAs have a sequence of 3 shapes on them that match a codon of RNA. A
codon is a set of three RNA nucleotides that have the information for the addition of a specific
amino acid. So the tRNA is like the translator that translates the message from RNA code into a
protein.
Vocabulary
• Nucleotide- a single unit of DNA/RNA material(base + sugar + phosphate)
• Codon- three nucleotides which contain the message for a single amino acid
• Amino acid- a single building lock of protein
• Mutation- a change in a DNA sequence
• tRNA( transfer RN)- the translator between a codon and an amino acid
• Sequence- the pattern and order of different nucleotides in a strand of DNA or different
amino acids a protein
Materials (for 7 groups of 3 students each)
• Writing utensil
• Worksheet
• DNA nucleotides
• RNA nucleotides
• tRNAs
• Amino acids
• Pink or Red colored pencils
• Cake!
DNA nucleotides, RNA nucleotides,
Preparation
tRNAs, and Amino acids
All pieces must be assembled in groups so
that there are enough of each piece for each
group. The worksheet may need to be modified depending on the grade level and background
knowledge of the students.
Procedure
1. Introduction: Dartmouth scientist, part of what I study is DNA – 2 minutes
2. Hook: Which proteins do 7th graders need? Help me find out!- 2 minutes
3. Background: See previous, additionally models and how they may differ and introduction to
the pieces of my model – 15 minutes
4. Inquiry: Given a DNA sequence, students must use their kit“pieces”to determine the RNA
sequence, tRNA sequence, and amino acid sequence of the “protein”. This will spell out a
word. Students will do multiple sequence. (See worksheet) -25 minutes each day
5. Extend the Inquiry: Next, given a mutated protein, work backwards to figure out the DNA
sequence and where the mutation is. Fix the mutation and get a treat!
6.
More Inquiry: Design your own “proteins,” research diseases causde by single mutations
online, and determine the effects of INDEL mutations.
7. Data collection: Worksheets
8. Share: A review of the results of their worksheets at the end of the session – 5 minutes
9. Lesson/wrap: Importance of DNA in everything from fruit, to people to bacteria. How that
relates to students, and how I use it every day. What is the effect of a mutation in real life?
Are they always bad? What about “good”mutations?
10. Additional Inquiry: Perform “frameshift mutations” with the nucleotides. Look at how a stop
or start codon could effect a sequence.
Extensions
Students:
• Try to make there own DNA codes for different proteins corresponding to other words.
• Investigate diseases caused by single point mutations of nucleotides in DNA.
• Consider the effects of INDEL mutations.