Download Quick Links

VGEC: Teacher Notes
Wear a Chimp on Your Wrist
An activity that explores the base pairing rules in DNA. Students work out the matching sequence to a given
30 base-pair DNA sequence using the base-pairing rules. They then use coloured beads to produce a twostranded bracelet that matches their DNA sequence.
Learning objectives
To understand the base pairing rules of DNA, and the way in which the sequence of one DNA strand
specifies the sequence of a matching strand.
To understand the way in which some DNA sequences are shared by different organisms, but differ
from species to species.
Possible curriculum links
Key Stage 4: 5c Organisms and health
Files and folders provided
1 Chimp.docx/rtf/pdf
This document – includes Teacher Notes and Student Handouts.
2 SpeciesAlignment.docx/rtf/pdf
(optional)
3 BeadColours.pdf
A handout that compares the DNA sequences of the organisms
A handout showing the bead colours for the bases (optional).
4 DNASequences30BP.docx/rtf/pdf
Folder: Contains the 30 base-pair DNA sequence sheets.
Key vocabulary
DNA (short for deoxyribonucleic acid): the material from which genes are made.
Base pair: a pair of complementary nitrogenous bases that form the structure of DNA by holding the
two strands of the double helix together. The bases pair in a specific way: adenine (A) always pairs with
thymine (T) and guanine (G) always pairs with cytosine (C).
Genetic code: the order of the bases along a single strand of DNA.
Procedure
Students pick a sheet for the animal they want. They can choose DNA from the following living things:
human, chimp, elephant, grizzly bear, wallaroo (a relative of the kangaroo), owl, python, salmon, fruit fly
and maize.
Students complete the bottom half of the sequence on the sheet using the DNA base pairing rules.
Virtual Genetics Education Centre: http://www.le.ac.uk/genetics/genie/vgec/
1
A pairs with T
G pairs with C
Students make a bracelet to match their sequence using double-stranded thread and coloured beads.
The colour code for the beads is:
A is BLUE
T is ORANGE
G is GREEN
C is YELLOW
Materials
Print-outs of the DNA sequences. If these are laminated, they can be used over and over again.
Beads – blue, orange, green and yellow. (We use opaque plastic 9 × 6 mm beads from toy and hobby
shops.)
Thread for DNA bracelets. To form a double-stranded thread, fold a 550 mm length of thread back on
itself and tie a loop at one end. (We use clear 1 mm stretch plastic thread.)
Scissors (to trim the bracelets) and pens.
Background notes
The gene sequence that was used for all the different organisms is the first 30 bases of the cytochrome
b gene.
This gene is involved in helping to release energy from food. Almost all life on earth gets energy from
food in the same way, which is why this gene is found in everything from plants to humans.
As you can see, the DNA sequence of the gene doesn’t need to be the same for the protein produced
from it to do the same job. However, more closely related animals do tend to have a more similar DNA
sequence for the same gene. (You can see that there are very few differences between the chimp and
the human DNA sequence.)
DNA is a double-stranded chemical made up of pairs of building blocks called nucleotides. There are
four different types of building blocks, called A, G, C and T. A DNA sequence is made up of a
sequence of A, G, T and C in a specific order, as read along one of the two strands of DNA.
As the students make their DNA bracelet they will need to follow the pairing rules so that they are
making both of the matching strands that make up the structure of DNA:
A always pairs with T
G always pairs with C
Because of these pairing rules, you just need to know the sequence of one strand of DNA to work out
the sequence of the other stand of DNA which produces to complete DNA structure.
For example, if you have a DNA sequence:
AGGTACCTAGT
You can use the pairing rules to work out the sequence on the other side of the DNA structure:
TCCATGGATCA
So the double-stranded sequence of DNA would look like this:
AGGTACCTAGT
TCCATGGATCA
Virtual Genetics Education Centre: http://www.le.ac.uk/genetics/genie/vgec/
2
VGEC: Student Handout
Wear a Chimp on Your Wrist
1
Pick a sheet for the animal you want. You’re going to make a bracelet to represent part of their DNA
You can choose DNA from the following living things:
Human
Chimp
Elephant
Grizzly bear
Wallaroo (a relative of the kangaroo)
Owl
Python
Salmon
Fruit fly
Maize
2
Complete the bottom half of the sequence on the sheet using the DNA base pairing rules.
A pairs with T
3
G pairs with C
Make a bracelet to match your sequence using the double-stranded thread and the coloured beads.
The colour code for the beads is:
A is BLUE
T is ORANGE
G is GREEN
C is YELLOW
4
Congratulations! Now you can wear your DNA bracelet.
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/