The correct answer is D. Rosalind Franklin reportedly was "two steps away" from solving the DNA structure. Crick and Watson gained knowledge from Franklin's work, solved the mystery, published the findings, and received the recognition. Chargaff contributed to the discovery of the double helix with his earlier research.

B is the correct answer. Miescher isolated a DNA sample from salmon sperm. His student, Altmann, later named it nucleic acid. Alfred Hershey and Martha Chase were a scientific team that showed that DNA is the genetic material.

The correct answer is B. DNA produces RNA that codes for proteins. Choices A, C, and D are all out of sequence.

B is the correct answer. It is possible for different proteins to be produced by assembling the exons in a different sequence. Mutations do occur, but are less likely than re-sequencing exons. Transcription is not likely to start at the wrong place. Different ribosomes will produce the same proteins.

C is the correct answer. Genetic information is coded in the nucleotide sequences, specifically the triplets of bases called codons. DNA contains nucleotide bases, not amino acids. The sugar-phosphate backbone does not contain the variety of molecular structure necessary to carry genetic information. There is no RNA strand in the DNA molecule.

The correct answer is D. Most of the nucleotide sequences in human DNA are non-coding. Each gene sequence codes for a different protein. At most, only one protein would be affected. All codons code for some amino acid. A mistake is most likely to be in a non-coding section.

D is the correct answer. Processing of mRNA after transcription removes the non-coding introns. While it is true that a cap and tail are added, the additional length is small compared to the length of the excised introns. A gene sequence codes for a single strand of mRNA that is processed, but not combined.

B is the correct answer. mRNA contains the transcribed information for a specific polypeptide. Ribosomes, tRNA, and rRNA are all part of the mechanism for assembling all polypeptides.

D is the correct answer. Homeotic genes are expressed early in embryonic development and are responsible for overall body plans, including placement of limbs and anterior versus posterior ends. Choices A, B, and C are regulated by other genes.

B is the correct answer. During conjugation, one bacterium extends a tube of cytoplasm to temporarily join with another bacterium. The tube is used to transfer a replica of the original cell's plasmid. Transfection refers to the introduction of DNA into eukaryotic cells. Transcription refers to the process of DNA being copied by RNA to produce a complementary RNA. Translation is preceded by translation; it is the decoding of mRNA to produce a specific polypeptide.

The correct answer is C. Conjugation occurs in cells that have the F plasmid form of the F factor. All bacterial cells contain plasmids, but not all have the F factor on the plasmid. The R plasmid (not factor) is the gene that conveys antibacterial resistance. There is no C factor.

B is the correct answer. Specificity factors alter RNA polymerase, making it less likely to bind to promoters. Housekeeping genes are always turned on. Operators are sites on DNA where repressor proteins bind.

B is the correct answer. Most of the nucleotide sequences in human DNA are non-coding. If these non-coding sections, or introns, are included in the plasmid, they will also be turned on and begin coding for amino acids, producing a completely different protein. Although the plasmid is, in a sense, artificially mutated by the insertion of the human DNA, this does not explain the different protein synthesis. Choice D is incorrect because the inserted DNA is spliced into the plasmid by an enzyme.

The correct answer is D. Southern blotting is a means of transferring DNA markers from a gel to special paper, then tagging these DNA markers with a radioactive tag so they can be photographed.