DNA The molecule of heredity. The molecules of DNA is the information for life (determine an organism’s traits) DNA achieves its control by determining the structure of proteins.

DNA Deoxyribonucleic Acid nucleotides are the building blocks of nucleic acid

The Structure of Nucleotide DNA is made of repeating subunits called nucleotides. Nucleotide – –Simple sugar –Phosphate group –Nitrogenous base. Phosphate group Sugar Nitrogenous base

The simple sugar in DNA is called deoxyribose which gives DNA its name In DNA, there are four possible nitrogenous bases: –adenine (A) –guanine (G) –cytosine (C) –thymine (T).

Nucleotides join together to form long chains –the phosphate group of one nucleotide bonds to the sugar of an adjacent nucleotide(they form the backbone of the chain) the nitrogenous bases stick out like the teeth of a zipper.

The DNA molecule is a double helix. It contains two strands of nucleotides, in a spiral shape –Sugar- phosphate chains on the outside with the nucleotides in the inside. –The nucleotides held together by H bonds between A and T, and also between G and C. (Base Pairs)

The sequence of nucleotides on one strand is matched perfectly to a complementary sequence on the other strand. In DNA, the amount of A = amount of T, and the amount of G = amount of C.

The importance of nucleotide sequences The sequence of nucleotides forms the unique genetic information of an organism. The closer the relationship is between organisms, the more similar their DNA nucleotide sequences will be.

DNA Replication Process where DNA copies itself

Separation of strands –bonds are broken between complementary base pairs

base pairing –The bases of free nucleotides pair with the bases of the original DNA strands –Each strand builds a complementary strand

Results of DNA replication –2 DNA molecules –Each consists of an original strand of nucleotides and a new strand

Errors sometime do occur The wrong nucleotide is added to the new strand A protein (enzyme) that proofreads the new DNA strand and corrects the mistake

%20long%20.htmlhttp:// %20long%20.html