dna deoxyribose nucleic acid say: dee-ox-ear-i-bose new-clay-ik a-sid (genetic material)
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DNADeoxyribose Nucleic Acidsay: dee-ox-EAR-i-bose
new-CLAY-ik A-sid(Genetic Material)
Ka Hana ‘Imi Na‘auao – A Science Careers Curriculum Resource Go to: www.cds.hawaii.edu/kahana
What is DNA?
• DNA is the genetic material of all living things on the planet.
• It is found in the nucleus of your cells.
• DNA holds the instructions to make all things in your body work properly.
Where is DNA found?• DNA is found
in the nucleus of all plant and animal cells.
• It is wound up in tight chromosomes.
What does DNA look like?• Shape of a double helix or a
twisted ladder.• The steps of the ladder are
called “base pairs”• The bases:
Adenine (A) say: A-da-nineGuanine (G) say: GWAY-nineThymine (T) say: THIGH-minCytosine (C) say: SITE-oh-seen
Base Pairs
• Each of the bases have a partner they pair off with.
• Adenine (A) always partners with Thymine (T)
• Cytosine (C) always partners with Guanine (G)
ACGTG
TGCAC
Complementary Strand
What is the complementary strand for the following sequence?
A A T C GG T C A GTT CA G A C
T T T T TA A A AG G G GCCCC
Mistakes Happen
• If the wrong bases pair off with one another it’s called a mutation.
• Most mutations are harmless.
• Some can be serious.
ACGTG
TGACC
DNA Replication
• This is when DNA makes a copy of itself.
• Usually when the cell divides, a copy of the instructions (DNA) is given to the new cell.
How does DNA control the cell?
• A cell’s DNA needs to change forms.• DNA cannot leave the nucleus to give
commands, so it needs to make a smaller copy of itself called RNA.
• RNA leaves the nucleus and is read by the ribosome. say: RYE-boh-sohm
• The ribosome then makes a protein.• The protein is DNA’s command.
Making RNA
DNA
RNA
DNA Unwinds
RNA is made
RNA has DNA’s instructions and can leave the nucleus
Changing DNA to RNA
• Transcription• To figure out the RNA sequence,
base pairs still need to match up.• A with T, C with G (for DNA)• In RNA the rules still apply, but
anywhere a T should be, it is replaced by Uracil (U). say: YUR-uh-sill
What is the RNA sequence?DNA RNA
T
A
T
C
G
T
G
A
A
U
A
G
C
A
C
U
What is a gene?
• A gene is a section of DNA that has instructions for a particular trait.
• Some genes are dominant (stronger)
• Some genes are recessive (weaker)
• Each organism inherits a gene from each parent.
• Each organism has 2 genes per trait.
Inheritance
• In the example, each flower has a trait for color: red or yellow.
• The offspring inherited a red gene from one parent and a yellow gene from the other parent.
• Red was the expressed color, so it is considered dominant.
Where did the color come from?
• There was a section of DNA which had the information for color.
• The RNA form is made and read into a protein that expresses the color.
DNA
RNA
Protein
Expressed color
References• http://www.pitt.edu/~hpsdept/images/double_helix.gif, Access Date: Dec. 12, 2006• http://www.bst.ntu.edu.tw/images/double%20helix%20c.jpg, Access Date: Dec. 12, 2006• http://www.chemsoc.org/ExemplarChem/entries/2003/imperial_Burgoine/origins.txt.html, Access Date:
Dec. 12, 2006• http://library.tedankara.k12.tr/chemistry/vol1/biochem/trans98.jpg, Access Date: Dec. 12, 2006• http://biology.unm.edu/ccouncil/Biology_124/Images/transcription.gif, Access Date: Dec. 13, 2006