Module 2, 3, 4

1
Module 2, 3, 4

• Paper DNA
• Candy DNA
• DNA from an Onion

2
Module 2Paper DNA

• Part 1 DNA Replication - DNA Structure and Base
  Pair Rules
• Part 2 Transcription DNA to mRNA, 3 Letter
  Code and Genes
• Part 3 Translation mRNA to Protein

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Parts 1 DNA Structure, Base Pair Rules, and DNA
Replication

• This activity is a great way to break ice with a
  large group.
• Do any PPT presentations before breaking for the
  activity.
• Use this before any lab-type activities.

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A C G T

• See animation of the activity on the next slide.
• Print very large ACG or T, each on different
  coloured paper
• Select enough base pairs of letters for each
  student.
• Group the students into 4 groups by letter. Let
  half of each group chose to line up in any order
  they like. Have them put their R hand out.
• Have one student or LTS volunteer act as the
  polymerase and put the left hand of each
  student on the right shoulder of the student on
  the left. LTS volunteers can be in the sequence,
  but one should help the Polymerase.
• Assign one student who base pairs with the last
  student in the line to be the primer. Have
  this student face his base pair match and shake
  hands and hold. This starts the other strand of
  the DNA.
• Have the students reiterate the base pair rule.
  Ask who goes in next in the sequence. Have one
  of the next base pairs face the next student on
  the first strand, shake and hold hands. Have
  polymerase link hand to shoulder.
• Continue until all students are in the DNA
  molecule.
• Explain that this is pretty much how DNA
  replicates for cell division.

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DNA Structure, Base Pair Rules, and DNA
Replication
A
C
G
T
C
G
T
A
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Part 2 DNA to mRNA
the bad old cat saw the eht dab dlo tac was eht
big ape and ran and bit him gib epa dna nar dna
tib mih

• To have students understand that DNA has a 3
  letter code, and to see how a gene is built and
  a bit about how DNA will be transcribed.
• Print the full sentence with one word per sheet
  of paper (very large of course). Also print the
  non-coding strand/tRNAs on another colour. On
  the back of the tRNA, print the amino acids.
  See PDF file. The sentence there is longer than
  this enabling this activity with more than 30
  people. For smaller groups, leave out words but
  keep enough words that the sentence makes sense.
• Help the students with the sentence get organized
  into a line.
• Things to say If this were one strand of DNA,
  the code would make sense.
• Have the non-coding students find their match.
• Things to sayDNA on the other strand, would
  not.

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DNA to
The bad old cat saw the eht dab dlo tac was eht
big ape and ran and bit him gib epa dna nar dna
tib mih
.

• If this sentence was a gene
• On one strand of DNA, the code would make sense.
  
• On the other strand, the code would not.

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Part 3 RNA to Protein
the bad old cat saw the big ape and ran and bit
him .
S W O R D S B A I T I N G

• The gene is transcribed to mRNA
• If this were RNA, there is a start and a stop
  codon (the first and last words)
• Each 3 letter DNA/RNA codon stands for 1 letter /
  amino acid in the final protein.

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Part 3 RNA to Protein
the bad old cat saw the big dog and ran and
bit him
eht dab dlo tac was eht gib god dna nar dna
tib mih
S W O R D S B A I T I N
G

• For mRNA codons, there are transfer RNAs that
  bring the amino acid to the ribosome.
• Most tRNAs have an anticodon to match up to the
  mRNA codon. The ribosome links the amino acids
  into the protein chain.
• Like Polymerase that links the bases in DNA,
  the amino acids are linked by Ribosome in this
  version
• During the base pairing in this game the protein
  sequence will be backwards, so have students let
  go of the shoulder link, turn around and
  re-bond! Now the protein should make sense.

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Module 3 candy dna
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partnership program
Thanks to our sponsors
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Candy DNA NO EATING THE CANDY DURING THE LAB
PLEASE ?
13
The making of this biotech kit is a collaboration
between the following Lets Talk Science
Partnership sites
and
Project support provided by
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Making a Candy DNA Molecule

• Method
• Long candies make up the backbone of the DNA
  ladder one candy is the phosphate, the other is
  the (deoxyribose) sugar group

NO EATING THE CANDY DURING THE LAB PLEASE ?
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Making a Candy DNA Molecule

• Method
• Divide the soft candies into four different
  colours. Assign names to the each of the four
  colours to represent the nucleotide bases

NO EATING THE CANDY DURING THE LAB PLEASE ?
Images from http//nobel.scas.bcit.ca/resource/dn
a/dna_sweets.htm
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Making a Candy DNA Molecule

• Method
• Connect the two sides of the backbone with soft
  candies using a toothpick (think of the soft
  candies as the steps of the ladder)
• Remember only certain nucleosides can stick
  together in DNA
• Make a key and indicate which candy represents
  which part of the DNA molecule Phosphate,
  Deoxyribose, the Nucleosides

NO EATING THE CANDY DURING THE LAB PLEASE ?
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Making a Candy DNA Molecule
Image from http//nobel.scas.bcit.ca/resource/dna
/dna_sweets.htm
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A Chemical Model
http//www.ch.cam.ac.uk/magnus/molecules/nucleic/d
na1.jpg
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Module 4 DNA Isolation
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partnership program
Thanks to our sponsors
21
Extracting DNA Where can you find DNA?
22
The making of this biotech kit is a collaboration
between the following Lets Talk Science
Partnership sites
and
Project support provided by
23
Extracting DNA from an Onion

• Materials
• Onion
• 1 cup (250 mL) of cold water with 1/2 tsp (2 mL)
  of salt
• 1/4 cup (50 mL) of dishwashing liquid diluted
  1/10 with water (5 mL dish soap 45 mL water)
• Meat tenderizer
• Strainer
• Rubbing alcohol (on ice or in freezer)
• Ice
• 2 Cups or beakers Label them CONTROL and
  EXPERIMENT
• Strainer
• Glass rods
• Test tubes

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Extracting DNA from an Onion

• 1) Coarsely chop onions and divide them in half.
  Label your cups or beakers one as CONTROL and
  one as EXPERIMENT.

http//nobel.scas.bcit.ca/resource/dna/images/edit
ed/2555_dnaComingOut2.jpg
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Extracting DNA from an Onion

• 2) Place half the onions in the CONTROL and the
  other half in the EXPERIMENT cup/beaker.
• Add 50 ml of cold salt water to each cup.

http//nobel.scas.bcit.ca/resource/dna/images/edit
ed/2555_dnaComingOut2.jpg
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Questions

• Why is the salt added?
• Without the salt, we wont be able to isolate
  the DNA.
• Youll see in a bit!

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Extracting DNA from an Onion
3) Add 50 mL of 1/10 diluted dishwashing soap to
the cup marked EXPERIMENT. Dont add anything
to CONTROL.
TIP Use clear or lightly coloured detergent
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Questions

• What does the detergent do?
• The detergent pulls apart the lipids and
  proteins in the cell membranes that surround the
  cell and nucleus. Once these membranes are broken
  apart, the DNA is released from the cell. The
  detergent also stops the DNA from sticking to
  proteins floating in the solution.

http//learn.genetics.utah.edu/units/activities/wh
eatgerm/background.cfm
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Extracting DNA from an Onion
4) Add 1/2 teaspoon (2 mL) of meat tenderizer to
the cup/beaker marked EXPERIMENT nothing to
CONTROL. Stir gently and wait 10 minutes.
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Questions

• Why add the meat tenderizer?
• The meat tenderizer has Papain, an enzyme that
  chops up or digests proteins. Normally DNA is
  wrapped around and packaged within clusters of
  protein balls called histones. The enzymes in the
  meat tenderizer essentially chop up the protein
  balls that the DNA is wrapped around.

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Extracting DNA from an Onion

• 5) Separate the onions from the juice with a
  strainer. This takes about 10 minutes.

http//museumvictoria.com.au/scidiscovery/images/m
n005092_w150.jpg
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Extracting DNA from an Onion
6) SLOWLY pour an amount of alcohol equal to the
solution you have into each cup/beaker/test tube
and DO NOT stir.
TIP See if you can make a layer of alcohol over
the onion solution.
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Extracting DNA from an Onion
The DNA is the white strings in the alcohol
layer.
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Questions

• Why add the alcohol?
• Alcohol makes the DNA precipitate out of
  solution. DNA is insoluble in alcohol and
  soluble in water. Thus, we see the DNA float up
  as strings in the alcohol layer.

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Extracting DNA from an Onion
7) Spin the DNA using the glass rod.
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Questions

• What does the detergent do?
• Why add the meat tenderizer?
• Why was the salt added?
• Why did you add the alcohol?
• What happened in the CONTROL?

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Questions

• What is the largest cell you have seen?
• What happens when you boil an egg?
• Why do we not see the DNA?
• How could you prove you had DNA and not denatured
  protein?

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?
ANY QUESTIONS?