DNA Deoxyribonucleic Acid

Document Sample
DNA Deoxyribonucleic Acid Powered By Docstoc
Deoxyribonucleic Acid
           Watson and Crick
           Remember them?
• James Watson and Francis Crick are
  credited with the discovery of the secret of
  the double stranded helix of DNA in 1953.
              What is DNA?
• DNA is the chemical
  at the center of the
  cells of living things
  which controls
  structure and purpose
  of each cell and
  carries genetic
• DNA is the blueprint
  of life
• DNA can be used to detect and help
  determine treatments of diseases, catch
  criminals, and many more exciting
  discoveries in agriculture too.
              DNA is……..
• in every cell of your body. DNA is the
  same in each and every cell; whether it is
  the liver, skin, blood, hair, pancreas, and
  so on the DNA is the exactly the same.
  (exception RBC’s don’t have a nucleus
  when mature)
• It identifies you!
Let’s take an animated tour of What
            DNA is…….
• http://learn.genetics.utah.edu/units/basics/t

• Tour of Basics Q and A to be placed in
     Chromosomes and DNA
• Ours genes are on our chromosomes
• Chromosomes are made up of a chemical
  called DNA
• Each person has 46 chromosomes
• The base pairs of DNA are like sentences
  called genes. Genes tells cells to make
  proteins and proteins have the cell to
  perform specific functions.
              DNA structure
• DNA is known as the
  double stranded helix.
  It resembles a twisted
          The double strands
• The two strands of DNA are antiparallel.

•It is antiparallel because of the direction
of the strands. When you look at the
nucleotides they are heading one way
along one stand and the other way along
the other strand
• For better understanding the antiparralel
  strands at their ends are lableled 5’ and 3’
  (called 5prime and 3 prime).People who
  work with DNA and enzymes reading
  nucleotide sequence always read in the
  5’to3’ direction. In a vertically oriented
  double helix, the 3' strand is said to be
  ascending while the 5' strand is said to be
• Carbon atoms of        .
  the sugar are
  numbered (prime ‘
  indicates carbon of
  the sugar)
• The phosphate of
  the nucleotide is
  attached to 3’ and
  to the 5’ of the
  adjacent nucleotide
• OH is attached to
  the terminal
• Gives DNA
  distinctive polarity
• In deoxyribonucleic acid (DNA) replication,
  the 5′ to 3′ DNA strand that is synthesized
  with few or no interruptions is the leading
  strand. The leading strand, "reads" the DNA
  and adds nucleotides to it continuously.

• In deoxyribonucleic acid (DNA) replication,
  the 3′ to 5′ DNA strand that is
  discontinuously synthesized as a series of
  fragments (Okazaki) in the 5′ to 3′ direction
  is the lagging strand.
         What is it made of ?
Hydrogen bonds
Deoxyribose sugar
Four nitrogen bases:
          DNA components
• Deoxyribose (sugar)
 phosphate make up
the sides of the DNA
molecule or ladder
• One deoxyribose together with its
  phosphate base make a nucleotide
• One strand of DNA is a polymer of a
• One strand of DNA has many millions of
         DNA components
• Nitrogen bases pair together to make what
  is called rungs of the ladder
           DNA components
         4 Nitrogenous Bases
• Adenine (A) always pairs with thymine (T)
  and guanine (G) always pairs with
  Cytosine (C)
          Pyrimidine Bases
• Thymine
• Cytosine
  – Each have one ring of carbon and nitrogen
             Purine Bases
• Adenine
• Guanine
  – Have 2 rings of carbon and nitrogen atoms
            Why A-T C-G?
• Each base pair is held together by
  hydrogen bonding
• A and T are held together by 2 hydrogen
• G-C are held together by 3 hydrogen
• The pairing of the bases is like a piece in a
  puzzle, this is just the way they fit!!!
          DNA components
• Bases attach to the sugar on the sides of
  the DNA around 10 base pairs per turn
          Functions of DNA
• The order of the nitrogen bases
  determines which proteins are produced
  by the cell
• Every aspect of life is determined by
  protein functions
• The proteins do all the work of the cell
  – Determine physical characteristics (genes)
    hair color, eye color, freckles, etc.
  – Play a part in chemical reactions in body
• Each cell has about 2m of DNA
• The average human has about 75 trillion
  cells sooo…..
  – DNA can go from earth to the sun more than
    400 times
 Now let’s see how we can extract
• http://learn.genetics.utah.edu/units/biotech

Shared By: