Cytosine (C) makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine (T)?

Write the base sequence and label the 3' and 5' ends of the complementary strand for a segment of DNA with the following base sequences:

d. 5'CGCGATATTA3'

Fill in the following table with the analogous nucleic acid structures:

Write the complementary base sequence for each of the following DNA segments. Indicate the 5' and the 3' ends.

b. 5'ATAGCCCTTACTGG3'

Four species shown below give the percentages of A–T pairings vs G–C pairings. Based on only the information given, which species would have the most significant strength in their base interactions?

Four species shown below give the percentages of A–T pairings vs G–C pairings. Based on only the information given, which species would have the most significant strength in their base interactions?

Draw the structures of adenine and uracil (which replaces thymine in RNA), and show the hydrogen bonding that occurs between them.

DNA and RNA, like proteins, can be denatured to produce unfolded or uncoiled strands. Heating DNA to what is referred to as its “melting temperature” denatures it (the two strands of the double helix become separated). Why does a longer strand of DNA have a higher melting temperature than a shorter one?