Download DNA in a Bottle

STEM%Outreach%at%CU%Denver%
Activity'Description'
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DNA%in%a%Bottle%
Contributed'by:'Community'STEM'Clubs'Program'
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Purpose:'to'introduce'students'to'the'basics'of'DNA'
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Background%
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Deoxyribonucleic'Acid'(DNA)'carries'the'genetic'information'vital'to'the'
development'and'functionality'of'living'organisms.'These'biological'
instructions'are'encoded'into'DNA’s'chemical'structure'as'nucleotide'chains.'
In'extracting'their'DNA,'students'can'see'what'determines'their'blood'type,'
their'hair'color,'and'even'their'predisposition'to'certain'diseases.'
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Overview%
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This'activity'consists'of'mainly'two'parts:'instruction'and'a'lab'experiment.'
Students'will'be'introduced'to'basics'of'the'human'genome'and'DNA.'
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Materials%
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500'mL'per'10'students'–'drinking'water'
1'Tbsp'per'10'students'–'salt'
100'mL'per'10'students'–'isopropyl'alcohol'
2'per'10'students'–'large'cup'or'beaker'(at'least'500'mL)'
1'per'student'–'clear'(plastic)'cup'
1'per'student'–'coffee'stirrer'or'hot'straw'
1'per'student'–'take'home'size'plastic'bottle'(think'party'bubble'container)'
petri'dish'or'extra'cup'
dish'soap'
food'coloring'
superglue'
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DNA%Structure%
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Our'presentation'begins'by'building'up'to'a'complete'DNA'structure.'Starting'
with'the'four'nitrogen'bases'(adenine,'cytosine,'guanine,'and'thymine)'we'
add'the'ribose'and'phosphate'groups'while'adding'comments'and'discussion'
about'each.'We'then'talk'about'how'the'nitrogen'bases'pair'and'are'bonded'
together'to'form'a'DNA'strand,'and'how'DNA'packs'into'chromosomes'that'
are'visible'through'a'microscope.'With'a'broad'picture'in'place,'we'
contextualize'the'relative'size'growing'through'nucleotides,'genes,'DNA,'and'
chromosomes,'which'are'found'primarily'within'the'nucleus'of'cells.'
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A'message'to'keep'in'mind'throughout'is'how'we'start'with'something'so'
small'and'how'we'expect'to'be'able'to'see'the'DNA'once'it'is'extracted.'
STEM%Outreach%at%CU%Denver%
Activity'Description'
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DNA%Extraction'
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The'DNA'extraction'lab'proceeds'as'follows:'
1. Mix'500mL'of'drinking'water'with'one'(1)'Tbsp'salt'
2. Stir'mixture'until'salt'is'dissolved'
3. Transfer'three'(3)'Tbsp'of'salt'water'mixture'into'a'clear'cup'
4. Gargle'the'cup'of'salt'water'for'one'(1)'minute'
5. Spit'the'salt'water'back'into'the'cup'[cheek'cells'are'suspended'in'the'
salt'water]'
6. Put'one'(1)'drop'of'soap'into'cup/petri'dish.''
7. Rub'a'stirrer'end'in'the'soap'and'use'that'end'to'slowly'stir'in'a'single'
direction'(avoid'bubbles)'the'salt'water'mixture'with'cheek'cells'
[soap'releases'DNA'by'breaking'down'cell'membranes]'
8. In'a'separate'cup,'mix'100mL'of'isopropyl'alcohol'and'three'(3)'drops'
of'food'coloring.'
9. Tilt'the'salt]water'cup'and'gently'pour'in'the'colored'isopropyl'
alcohol'until'it'forms'a'2cm'layer'on'top.'
10. Wait'approximately'2.5'minutes'for'white'clumps'and'strings'to'start'
forming'[that’s'the'DNA]'
11. Fill'a'small'“take'home”'bottle'with'isopropyl'alcohol'
12. Stir/twirl'the'stirrer'in'one'direction'to'wind'DNA'strands'around'the'
stirrer'(avoid'mixing'isopropyl'alcohol'and'water)'
13. Shake'the'DNA'on'the'stirrer'into'the'take'home'bottle.'
14. Top'off'the'bottle'with'isopropyl'alcohol'and'superglue'the'cap'shut'
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Modifications%and%Extensions%
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The'instruction'portion'can'be'tailored'to'many'student'levels.'From'basic'
genetic'inheritance'in'the'work'of'Gregor'Mendel'to'more'complex'
discussions'on'gene'expression'and'regulation,'there'is'a'genetic'discussion'
accessible'to'any'level.'In'particular,'there'are'common'misconceptions'
about'genetics'and'DNA'that'can'be'addressed.'
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Rather'than'cheek'cells,'DNA'can'be'extracted'from'practically'any'living'
organism.'In'the'classroom,'strawberry,'broccoli,'and'split'pea'DNA'can'be'
extracted'with'the'addition'of'a'blender,'strainer,'and'meat'tenderizer.'
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The'details'of'how'the'ethanol'precipitation'relies'on'some'basic'chemistry'
and'could'offer'higher]level'students'with'an'interesting'topic'of'
conversation.'
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The'following'trivia'facts'about'DNA'can'make'a'fun'game.'
- Human'beings'share'a'common'99%'of'DNA'code'
STEM%Outreach%at%CU%Denver%
Activity'Description'
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- The'DNA'from'a'single'human'put'end'to'end'could'travel'to'the'sun'and'
back'over'600'times'(moon'and'back'6000'times)'
- Typing'at'60'words'per'minute,'it'would'take'~50'years'to'type'the'
human'genome'
- Errors'are'caused'by'alterations'to'a'human’s'DNA'about'1000'times'a'
day'
- DNA'was'discovered'in'1869'(by'Fredrich'Miescher)'but'not'understood'
as'genetic'material'until'1943'
- Mature'red'blood'cells'are'the'only'human'cells'without'DNA;'the'nucleus'
is'squeezed'out'to'make'room'for'carrying'hemoglobin'
- Humans'have'46'chromosomes'
- There'are'4'DNA'bases,'4'RNA'bases,'and'20'amino'acids.'
- There'are'about'3'billion'bases'in'our'genome'
- We'have'about'20,000]25,000'genes'
- Only'1.5%'of'the'human'genome'is'made'of'genes'
- A'complete'genome'takes'about'3'gigabytes'of'memory'to'store'
- DNA'in'one'cell'can'stretch'up'to'6'feet'long'(at'50'trillinths'of'an'inch'
wide)'
- Humans'have'98%'of'DNA'in'common'with'a'chimpanzee,'85%'with'a'
zebrafish,'60%'with'a'banana,'57%'with'a'cabbage,'36%'with'a'fruit'fly,'
21%'with'a'roundworm,'15%'with'rice,'and'2%'with'e.'coli'
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Some%References'
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http://ghr.nlm.nih.gov/handbook/basics/dna'
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http://www.genome.gov/25520880'
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http://www.genome.gov/10001772'
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http://www.nature.com/scitable/topic/genetics]5'
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http://www.hhmi.org/biointeractive/dna]packaging'
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http://knowgenetics.org/common_misconceptions/'
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http://learn.genetics.utah.edu/content/labs/extraction/howto/'
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http://bitesizebio.com/253/the]basics]how]ethanol]precipitation]of]dna]and]rna]
works/'
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Attachments'
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Basic'slides'for'instruction'on'DNA'structure'
Compiled'by'Axel'Brandt'as'part'of'the'CU'Denver'Community'STEM'Clubs'program.'Special'thanks'to'
What%is%DNA?%
DNA%Structure%
1.  Nitrogenous%Base%
DNA%Structure%
1.  Nitrogenous%Base%
2.  Ribose%Sugar%
DNA%Structure%
1.  Nitrogenous%Base%
2.  Ribose%Sugar%
3.  Phosphate%Group%
DNA%Structure%
DNA%Structure%
DNA%packaging%
h?p://www.hhmi.org/biointeracDve/dnaGpackaging%
Things%You%May%
Not%Know%About%
DNA%
h?p://learn.geneDcs.utah.edu/content/molecules/dnathings/%
%Extract%your%DNA%
from%cheek%cells%