History of DNA James Watson and Francis Crick are given most of the credit for discovering the...
-
Upload
tabitha-robbins -
Category
Documents
-
view
212 -
download
0
Transcript of History of DNA James Watson and Francis Crick are given most of the credit for discovering the...
DNA DNA NotesNotes
History of DNA
• James Watson and Francis Crick are given most of the credit for discovering the structure of DNA
• They used x-rays from Rosalind Franklin
determine the spiral shape
The Evidence and Models
• Rosalind Franklin’s Watson and Crick’s
X-ray of DNA original model
What is DNA Made Of?
• The backbone of DNA is made of:– Phosphate – Deoxyribose (sugar)
** These molecules alternate all the way down the side of the molecule
What’s in the middle?
• There are four base molecules– Adenine (A)– Thymine (T)– Cytosine (C)– Guanine (G)
• The bases form specific pairs– Adenine pairs with thymine (A-T) or (T-A)– Cytosine pairs with guanine (C-G) or (G-C)
Here is the full picture!
Nucleotides
• Nucleotides are the pieces that make up a strand of DNA
• Each nucleotide is made of:– A sugar (deoxyribose)– A phosphate– A base
Replication
• DNA replication occurs when a copy of the DNA is made
• Replication occurs during mitosis and meiosis
• If all goes well, the copy is identical to the original strand of DNA
Mutations
• A mutation is a mistake in the DNA that usually occurs during replication
• Not all mutations are harmful
• Types of mutations:– Insertion– Deletion– substitution
Insertion
• Extra bases are added to the strand
Deletion
• Bases are left out of the strand of DNA
Deletion
• Entire sections of chromosomes can be deleted
Substitution
• Bases are replaced with
different bases
Ex: sickle cell anemia
Substitution, con’t