Traits and Heredity: Dna

The video tutorial discusses the contributions of scientists like Martha Chase, Alfred Hershey, and others to the understanding of genetic material. It explains that DNA, or deoxyribonucleic acid, is the chemical that constitutes genes. The DNA molecule is described as a twisted ladder, known as a double helix, with rungs formed by pairs of nitrogen bases. These bases combine in specific ways to determine the genetic code.

How many different types of nitrogen bases are there in DNA?

What determines the genetic code in DNA?