C is correct...
Single-strand binding proteins (SSBs) are closely associated with DNA enzymes because they bind to separated single-stranded DNA (ssDNA) during replication, recombination, and repair, preventing the strands from re-annealing and forming docking hubs for various enzymes like DNA polymerase and helicase to access the DNA for processing.
Human cells do not have DNA polymerase III, as it is the primary replication enzyme found in prokaryotes like E. coli. Humans, as eukaryotes, use other DNA polymerases, such as DNA polymerase delta (δ) and epsilon (ε), to perform the function of replication, while also relying on other polymerases for specific roles like mitochondrial DNA replication or repair.
Prokaryotes:
Use DNA Polymerase III as the primary enzyme for both leading and lagging strand synthesis.
Eukaryotes:
Have evolved a more complex system with multiple DNA polymerases for different tasks.
- DNA Polymerase Alpha: Initiates DNA synthesis.
- DNA Polymerase Delta: Synthesizes the lagging strand and can perform leading strand synthesis.
- DNA Polymerase Epsilon: Primarily synthesizes the leading strand.
