Warm-Up

• Where is DNA found?

• What is DNA?

• What do you know about the structure of DNA?

Chapter 11DNA & Genes

Section 11.1 DNA: The Genetic Code

DNA (Deoxyribonucleic Acid)

• The main substance in chromosomes.

• It carries genetic information (determines traits)

• Replicates itself

• Makes RNA (Ribonucleic Acid)

• Makes proteins

DNA (Deoxyribonucleic Acid)

• Made up of Nucleotides – sugar, phosphate, and nitrogen base

DNA

• Double Strand - aka Double Helix

4 Nitrogen Bases• Adenine• Guanine• Thymine• Cytosine

Nitrogen Bases

• Adenine always combines with Thymine

• Guanine always combines with Cytosine

DNA• Sugar = Deoxyribose• The sugar and the phosphate group of the chain

and the nitrogen bases stick out like teeth on a zipper

DNA

• The stands of the molecule are made of alternating bonds of sugar and phosphate.

• The bases are connected to the sugar and held together by a weak hydrogen bond.

History of DNA

• James Watson & Francis Crick formulated the model for DNA.

• Rosalind Franklin had taken many x-rays/pictures.

DNA Replication

• DNA copied during Interphase in the chromosomes

• 1. Hydrogen bonds break at the nitrogen base pairs

• 2. Strands unzip

• 3. Free floating nucleotides bond to the single strands

• 4. Product is 2 molecules of DNA

• DNA proving innocence

• http://youtu.be/PdUpbJsjnkc