Bio3400
Chapter 12
DNA Organization and Chromosomes
Bacterial and
chromosomes
usually consist of a single molecule, are much smaller than eukaryotic chromosomes, and largely devoid of associated
.
Bacterial and viral chromosomes are often
and underwound, resulting in a
compact,
conformation.
Distinctive banding
patterns
seen in
chromosomes represent paired homologs; bands may
exhibit
indicating gene activity.
chromosomes
in eukaryotes possess extensive DNA
where transcription activity can be visualized.
Eukaryotic DNA is complexed with
proteins
and bound up in repeating
units
called
.
The nucleosomes are condensed in several levels of DNA
packing
to form the compact
packed into the 10-µm nucleus.
Several
techniques
can be used to reveal
patterns
in mitotic chromosomes that are useful in identifying chromosomes.
Eukaryotic chromosomes often exhibit large amounts of
DNA.
Repetitive DNA includes
DNA
and
DNA
that mediate chromosomal migration.
The ends of linear eukaryote chromosomes contain
DNA
sequences that play a role in the normal process of cell aging.