|The non-coding sequences of a gene or pre-mRNA are ____.
|A ____ is a regulatory sequence upstream (5') of a gene.
|Purines have two ____ rings, whereas pyrimidines have one.
|A mutation can be an insertion, deletion, or ____ of nucleotides.
|The primary structure of DNA is its ____ sequence.
|During replication, ____ separates the DNA strands.
|A change in the sequence of a chromosome is a ____.
|In chromatin, DNA is spooled around proteins called ____.