The structure of the large ribosomal subunit from Haloarcula marismortui (PDB code: 1FFK) has been solved by x-ray crystallography. The 23S RNA contains 2922 nucleotides (758 A, 889 G, 739 C, and 536 U). a. Assuming a random distribution of nucleotides, how many four-mer sequences with the sequence G-N (any base)-R (purine)-A are possible? b. There are actually 21 GNRA tetraloops in the structure. What percentage of possible GNRA sequences actually formed tetraloops in the structure? A bacterial DNA polymerase moves at approximately 1000 base pairs per second when replicating DNA. The polymerase holoenzyme is approximately 110 A long. By what multiple of its length does the polymerase move forward along the axis of the DNA double helix in 3 seconds? Assume the DNA stays fixed and ignore the rotational component of the motion of the polymerase along the DNA.