Final Answer:
Satellite DNA is A-T rich, making it lighter than G-C rich DNA.
Step-by-step explanation:
DNA is composed of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Adenine pairs with thymine through two hydrogen bonds (A=T), while cytosine pairs with guanine through three hydrogen bonds (C≡G). The weight of a DNA molecule is determined by the sum of the molecular weights of its constituent bases. Since A-T base pairs have two hydrogen bonds compared to the three in G-C base pairs, A-T rich DNA is lighter than G-C rich DNA.
The molecular weight of a DNA molecule can be calculated by adding the individual molecular weights of its bases. The molecular weight of adenine is approximately 135.13 g/mol, thymine is 126.13 g/mol, cytosine is 111.10 g/mol, and guanine is 151.13 g/mol.
By considering the number of A-T and G-C base pairs in a DNA sequence, one can calculate the overall molecular weight. The A-T richness of satellite DNA contributes to its lighter weight compared to G-C rich regions. This difference in weight has functional implications, as A-T rich regions are often associated with specific functions such as satellite DNA's role in the structural organization of chromosomes or in centromere function.
Understanding the base composition and molecular weight of DNA is crucial for unraveling its structural and functional aspects within the genome.