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Explore the structure and composition of DNA, the blueprint of life, composed of nucleotides and paired bases forming a double-stranded helix. Learn the Base Pair Rule and differences between DNA and RNA.
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Structure and Composition DNA is sometimes called "the blueprint of life" because it contains the code, or instructions for building and organizing and ensuring that organism functions correctly.
DeoxyriboNucleic Acid • DNA is composed of subunits called nucleotides, strung together in a long chain • Each nucleotide consists of: a phosphate, a sugar (deoxyribose), and a base
Bases • Bases come in two types: pyrimidines (cytosine and thymine) • and purines • (guanine and adenine)
The sugar and phosphates make up the "backbone" of the DNA molecule.
The shape of the DNA molecule is a double-stranded helix (like a twisted ladder). • The sides of the ladder are composed of alternating sugars (deoxyribose) and phosphates. • The rungs of the ladder are composed of nucleotides. James Watson & Francis Crick
Base Pair Rule • Nucleotides pair in a specific way - called the Base-Pair Rule • Adenine always pairs • with Thymine (A-T) • Guanine always pairs • with Cytosine (C-G)
Here are some bases of DNA: • A -A-T-G-T-A-T-A-C-A-A-G-G-C-A-T • Now match them with their complementary bases.
RNA • RNA is like DNA • It stands for Ribonucleic Acid • It’s used to make proteins, whereas DNA contains the information of life