Deoxyribose Nucleic Acid
DNA…your book of life
• http://www.cbsnews.com/8301-3445_162-57556650/a-need-to-know-the-worst-news-you-will-ever-hear/
• Would you want to know?
2 Main Functions of DNA1.Carry the Code of Life-instruction manual for every living organism2. Blueprint for making proteins
The structure was discovered in 1953 by two scientists: James Watson & Francis
Crick
Double Helix=shape of DNA
Nucleotides are the basic structural units of DNA and consist of 3 things:1.Phosphate 2. Sugar (Deoxyribose)3.Nitrogen Base (Can be a Pyrimidine or Purine)
Watson’s Discovery Watson's Ideas
Nitrogen BasesPurine = Adenine (A), Guanine (G)
Pyrimidine =Thymine (T), Cytosine (C)*All 3 have a Y
Base PairingA-TC-G
Nitrogen Bases attached to Deoxyribose (sugar)http://www.dnalc.org/resources/3d/21-chargaff-ratios.html Chagraff’s Rule
Hydrogen bonds are the glue that hold
everything together
Sugar – DeoxyribosePhosphate Groups
(spacer)
Nitrogen Bases – Code of Life in ATCG
Thymine always pairs with Adenine
Guanine always pairs with Cytosine
A T
T A
C G
G C
G C
G C
What makes up the “Backbone” of the DNA Double Helix?
Which structure in the backbone is directly attached to the Nitrogen bases?
What are the “spacers” between each step?
Why were Mike&Ikes a good example for the purines?
Why were Skittles a good example for the pyrimidines?
DNA must replicate or make a copy of itself before a cell can divide.
•Play DNA Replication video from PBS in home folder
Remember Interphase?
DNA Replication – DNA makes a copy
of itselfImportant
during meiosis & mitosis because it makes sure
the daughter cells have the appropriate number of
chromosomes.DNAi animation
If the original strand of DNA is AATTGGCC
The complementary strand of DNA is TTAACCGG