Guanine-cytosine pairing forms three hydrogen bonds, instead of the two bonds formed by adenine and thymine. The other choices are all tempting, but subtly wrong. RNA contains uracil, DNA is the main storage form for information, mRNA is directly translated by tRNA, and ribosomes are important in the synthesis of proteins. It is worth noting that the 2' hydroxyl group of RNA's pentose sugar backbone is lost in DNA, which increases the stability and allows DNA to serve as a stable storage medium.

DNA strands are composed of millions of nucleotides. As a result, it would be virtually impossible to find a single strand that did not have all four nucleotides.

Nucleotides combine in purine-pyrimidine pairs due to the sterically appropriate fit of the bases, as well as the preferred combination of hydrogen bonds between the two nucleotides. As a result, two purines would not be seen combined. This is due to both being too large when together, and the incorrect hydrigen bonding between their functional groups.

DNA nucleotide base pairs are held together by hydrogen bonding. Cytosine and guanine are held together by three hydrogen bonds, where adenine and thymine are held together by only two. Increased hydrogen bonding within a strand of DNA will increase the melting point. The DNA segment with the most guanine-cytosine base pairs will have the highest melting point.

The term "degenerate codons" refers to codons with different nucleotide base sequences that specify the same amino acid. In the provided examples, two codons (UCU and UCA) both specify serine, indicating this is the correct answer.

The genetic code is unambiguous, because each codon only codes for one amino acid. It is also degenerate, so that each amino acid can be coded for by multiple codons. Choice 2 is incorrect, as the most 3' position on the mRNA is the wobble position.

Polynucleotide sequences are nucleic acids, so they must be DNA or RNA. Any sequence containing U (uracil) must be RNA, however there is no way to determine the type of RNA simply by looking at the sequence. This sequence could code for mRNA, rRNA, or tRNA.

mRNA is used to translate proteins. rRNA plays a structural and functional role in composing ribosomes. tRNA carries amino acids to the ribosome during translation.

Tryptophan, which is encoded on mRNA as 3'-UGG-5', is going to be transported to the ribosome via tryptophan t-RNA. The anti-codon loop must be complementary to the mRNA strand. Since the code for Tryptophan is 3'-UGG-'5, the anti-codon loop of the t-RNA must read 3'-CCA-5' in order to line up.

mRNA: 3'-UGG-'5

tRNA: 5'-ACC-3'

Degeneracy refers to the fact that more than one codon can code for the same amino acid. These codons generally differ in their third or "wobble" base. Degeneracy explains how there can be a total of sixty-four possible codons corresponding to only twenty amino acids.

Remember that DNA polymerase builds the new strand by reading the original DNA strand in a 3' to 5' direction. The newly formed strand will be read 5' to 3' and will have nucleotides that are complementary to the original strand.

During transcription, a complimentary RNA strand is constructed from a DNA template. It is important to realize that in RNA, the nucleotide base uracil is used instead of thymine as a complementary pair with adenine. The complementary strand is constructed 5’ to 3’ , but is lined up anti-parallel to the original strand.