Download How does it all work

How does it all work?
DNA
• Supplies instructions for cells.
• Is able to be copied
Chargaff
• Found that the bases bond together.
adenine= thymine and guanine=cytosine
Can you think of a mnemonic
device to remember which two
go together?
Rosalind Franklin
• Created images of DNA with x-rays.
Watson & Crick
• Built the double helix model
(“The Ladder”).
DNA Structure
• Is made of 4 subunits called nucleotides.
• All nucleotides are the same except for the bases
1 nucleotide
Nucleotides
• Each are made of a sugar, a phosphate, and a
base.
The Bases
• The 4 bases are adenine, thymine, guanine, cytosine.
• Each base is a different shape.
• Each base is called by their 1st letter.
Ex. A, T, G, C
• Each group of three bases codes
for one amino acid
See page 128 in your book!
Copying a Double Helix
Ex. In ACCGTGGC, what is
the other half of the Helix?
A T
C G
C G
G C
T A
G C
G C
C G
How does DNA work?
• 3 bases are organized to form a code of
instructions to tell the cell what to do or
how to copy…these instructions are called
amino acids.
But…how are the instructions
moved to a cell or other parts of
the body?
Proteins
• 50,000 different types
• They act as messengers to deliver the
amino acids (instructions).
• Are the building blocks of life!
Well, how does the DNA get on
proteins to move around?
What happens if there is a mistake
in the order of the bases on the
protein?
Mutations
• Occur when there is an error in the order
of the amino acids on the protein.
Ex. Deletion, substitution, insertion (extra)
Ex. Sickle cell anemia
Mutagen
• Is a physical or chemical agent that causes a
mutation in DNA.
Ex. Radiaton
Pretend you are a reporter for the New York
Times Science section. You have been
assigned to write a one-page, typed article
informing readers about why DNA has
been heralded as the most important
molecules ever discovered. The 1st
paragraph should explain the basic
structure of the DNA molecule; the 2nd on
why is DNA important.
This is your quiz for this set of
notes. You can use information
from your book, PowerPoint
notes, books from the library or
in the room or the Internet.
Paper is due on Friday
December 7, 2007