1. Structure and Function
DNA
Structure and Function

2. DNA introduction notes
Stands for DEOXYRIBONUCLEIC ACID.
Is present in ALL cells.
Is found in the NUCLEUS of eukaryotic cells and in the CYTOPLASM of prokaryotic cells.
Carries genetic information in the form of a code which is used for making PROTEINS.
Has a shape that is referred to as a DOUBLE HELIX it looks like a SPIRAL STAIRCASE or TWISTED LADDER.

3. DNA: Is made of subunits called NUCLEOTIDES. Each one has three parts:
A five-carbon SUGAR called DEOXYRIBOSE.
A PHOSPHATE group.
A nitrogenous (containing nitrogen) BASE. There are FOUR different bases, and therefore, FOUR different types of nucleotides found in DNA.

4. Types of Nucleotides PURINES PYRIMIDINES Phosphate group 5-C sugar
deoxyribose

5. DNA Structure
The SUGAR and PHOSPHATE units of the double helix alternate along the SIDES of the ladder.
The RUNGS of the ladder are made of two BASES held together by HYDROGEN bonds.

7. Base Pairing Rules:
There are four different types of nitrogen bases in DNA. They are
ADENINE
GUANINE
CYTOSINE
THYMINE
The four bases pair in very specific ways.
ADENINE only pairs with THYMINE.
CYTOSINE only pairs with GUANINE

8. Chargaff’s Rule
These base pairing rules are also known as CHARGAFF’S rule, because he was the researcher that first noted that the amount of adenine in any DNA sample was the same as the amount of thymine, and the amount of cytosine was the same as the amount of guanine.
Bases that pair with one another are called COMPLEMENTARY. The complement of adenine is THYMINE.

9. Let’s Practice Adenine = 20% Thymine = 20%
Cytosine = 30% Guanine = 30%
A T C G C T A T C G C T
T A G C G A T A G C G A
Section assessment 12-1 #2, 3, 4
Read and notes on section 12-2
Analyzing Data page 296 questions 1-3