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Cells and DNA
What is a cell?
 A cell is the basic unit of structure in a living
thing.
 Cells are microscopic.
 Living things are made up of trillions of cells!
Image source: http://www.jimmyjanesays.com/sketchblog/2007/04/plant-cell.html (Plant cell)
What is a cell?
 Animal cells are surrounded by a
boundary called a membrane.
Plant cells have a cell wall.
 Inside of cells are small
Image source: http://www.tracy.k12.ca.us/whssci/Derby/Derby-Physio.html (animal cell)
“organelles”. Like our organs,
these help the cell function.
 Organelles help make energy,
remove waste, store liquids…and
Image source: http://www.jimmyjanesays.com/sketchblog/2007/04/plant-cell.html (Plant cell)
The information center…
 How does a cell know what types of
molecules to make?
 The nucleus is inside the cell. This organelle
has all the information the cell needs to act.
 For example, it “tells” a hair cell how to be a hair
cell and not a skin cell.
Nucleus
Image source: http://www.jimmyjanesays.com/sketchblog/2007/04/plant-cell.html (Plant cell)
Information Storage
 The information in the nucleus is stored in
molecules called “DNA”.
 “Deoxyribonucleic Acid” – this molecule is
coiled in a special shape called a double helix
Image source: http://www.cusmibio.unimi.it/documenti/website_new/en/introduction/index2.htm
DNA
 DNA uses patterns and sequences
to provide information and
instructions to the cell.
 Your phone number…
 Area code: 541 = Oregon,304 = WV
 House number: 277-5084 = you!
Image source:
http://www.biologycorner.com/bio1/DNA.html
A
T
C
 DNA patterns are made up of four
G
DNA sequences and Genes
 The bases A,T,C,and G pair up on the DNA
molecule.
 Sequences of base pairs, called genes,
provide a “code” for a feature of the organism
 AAATTTCGAA = “yellow flowers”
Importance of DNA
 The way you, a flower, the cat develops….is
due to how your genes are expressed.
 Remember: Genes are segments of a long
DNA molecule.
One last thing…
 Mutations can damage a
cell and change how genes
are expressed.
 This can help or hurt the
organism, or be
neutral….but, usually it is
harmful.