DNADeoxyribose Nucleic Acidsay: dee-ox-EAR-i-bose

new-CLAY-ik A-sid(Genetic Material)

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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 StrandWhat is the complementary strand for the following sequence?

A A T C GG T C A GTT CA G A CT 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 RNADNA

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

TATCGTGA

AUAGCACU

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