Intro. to DNA & Genetics

Why/how do children resemble their parents? Heredity: the passing of characteristics from parents to offspring The study of heredity is what led to the study of genetics and DNA. Genetics: the science of heredity and of the mechanisms by which traits are passed from parents to offspring

DNA James Watson and Francis Crick are the scientists that pieced together a model and discovered the structure of DNA. Discovering the structure of DNA clarified how the DNA could serve as the genetic material. DNA=deoxyribonucleic acid

DNA Structure Double helix-two strands twisted like a winding staircase Each strand is made up of nucleotides. Every nucleotide is made up of three parts: phosphate group 5-carbon sugar nitrogenous base

DNA Structure The sugar (deoxyribose) and the phosphate group stay the same, but the nitrogenous base may be any of 4 different kinds Adenine Guanine Cytosine Thymine

DNA Structure Purine-two rings of carbon and nitrogen atoms Adenine and guanine are purines. Pyrimidine-a single ring of carbon and nitrogen atoms Cytosine and thymine are pyrimidines.

DNA Structure Base pairing rules-a purine on one strand always pairs with a pyrimidine on the other strand adenine – thymine (complementary base pairs) cytosine – guanine (complementary base pairs) Hydrogen bonds link the two nitrogenous bases together to connect the two strands.

Complementary Strand Practice: AAACCGTTGAGA GAGATCATAGCC CACGTTATACGA ATTTGCCAGACT TGCCTAAGGCAT