Key Takeaways

KEY TAKEAWAYS

• DNA is the genetic material in all cells but may not be the genetic material in viruses. • A nucleotide has a nitrogenous base, a deoxyribose sugar, and a phosphate group. • DNA is a double-stranded helix that has the nitrogenous bases making up the rungs of the ladder shape of the molecule. • RNA contains a ribose sugar, is often single-stranded, contains uracil instead of thymine, and is generally less stable than DNA. • The genome is the totality of the genes in a cell. A cell can be haploid, diploid, or polyploid, depending on the number of copies of DNA within the cell.