Chapter 12 DNA

Chapter 12 DNA

Define Vocabulary for Chapter 12 sections 1 and 2

 Read “The Role of DNA” on page 342-343


The Componants of DNA

 The full name for DNA is Deoxyribonucleic Acid.

DNA is a nucleic acid made up of nucleotides joint into long strands or chains by covalent bonds.


Nucleic Acids & Nucleotides


There are 4 nucleotides that make up DNA

Adenine- abbreviated A

Thymine- abbreviated T

Guanine- abbreviated G

Cytosine- abbreviated C

  Each Nucleotides will pair with another nucleotide to be called a base pair.  A pairs with T and C pairs with G.


Base pairs in DNA


Write the complementary strand for the following:


A            T          C           C           A            G               C                A              T


The work of Rosalind Franklin


In the 1950’s a Scientist by the name of Rosalind Franklin began studying DNA. Her work did not give much information about the shape of DNA but did lead the way for Watson and Crick to come up with their “model”.


The Clues in Franklin’s X-ray pattern enabled Watson and Crick to build a model that explained the specific structures and properties of DNA.

The Double Helix Model


DNA is the shape of a double helix, which looks like a twisted ladder.

The double helix model shows DNA with 2 strands that twist around each other like a spiral stair case.

See page 347 “Computer model of DNA”

Quiz on Chapter 12 Next week please see Homework tab for exact dates.