A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes):
Chromosome 1RNMDHBGKWU
Chromosome 2RNMDHBDHBGKWU
What term best describes this situation?

Four nucleic-acid samples are analyzed to determine the percentages of the nucleotides they contain. Survey the data in the table to determine which samples are DNA and which are RNA, and specify whether each sample is double-stranded or single-stranded. Justify each answer.

[A table of nucleotide percentages appears below the problem]

Consider the following segment of DNA:

    5'-...ATGCCAGTCACTGACTTG...-3'

    3'-...TACGGTCAGTGACTGAAC...-5'

How many hydrogen bonds are present in this DNA segment?

Consider the following segment of DNA:

    5'-...ATGCCAGTCACTGACTTG...-3'

    3'-...TACGGTCAGTGACTGAAC...-5'

How many phosphodiester bonds are required to form this segment of double-stranded DNA?

Consider the following segment of DNA:

    5'-...ATGCCAGTCACTGACTTG...-3'

    3'-...TACGGTCAGTGACTGAAC...-5'

If the lower strand of DNA serves as the template transcribed into mRNA, how many peptide bonds are present in the polypeptide fragment into which the mRNA is translated?