Final answer:
The direction of the DNA backbone provided by the structure 'Phosphate-C5-Sugar-C3' indicates a 5' to 3' orientation, which is also the direction in which DNA is synthesized.
Step-by-step explanation:
The structure of DNA consists of two antiparallel strands, each having a sugar-phosphate backbone. A phosphate group is connected to the 5' carbon of the sugar while the next phosphate is connected to the 3' carbon. This establishes a directional growth of the DNA chain from the 5' to the 3' end.
When considering the sequence provided that reads 'Phosphate-C5-Sugar-C3-Phosphate-C5-Sugar-C3...', we observe that the phosphate is bound to the 5' carbon (C5) and the 3' carbon (C3) end, indicating a sequence direction from 5' to 3'. DNA synthesis also occurs in this 5' to 3' direction, as new nucleotides are added to the 3' end of the growing strand.
The final answer to the DNA backbone orientation and synthesis direction is: (A) 5' to 3'.