Chapter
19
Quizzes:
Self
Activities
Chapter
Cum.
Videos
Movies
Words
Appendix
Summary
Art
Art
Unit 3: Genetics
Eukaryotic Genomes
Review
Eukaryotic
DNA is
packaged
with protein into
.
proteins bind to DNA in a 10-nm fiber of
"beads"
called
.
The nucleosomes are packed to
form
a
fiber.
The 30-nm fiber forms
looped
domains, making up a
fiber.
During mitosis, the looped domains coil and
fold,
forming the
chromosome.
Cells in most
multicellular
organisms undergo
driven by differential gene
, which can be regulated at several
stages.
Chromatin changes:
acetylation
of
"tails" loosens the configuration of chromatin and enhances
by making DNA more accessible to enzymes.
Transcription control:
many genes contain control elements such as
and
that can stimulate
transcription.
RNA Processing:
different
molecules can be produced from the same primary transcript, in a process called
alternative
RNA
.
mRNA Degradation:
single-stranded
(miRNAs) can lead to
degradation
of an mRNA or block its translation, thus limiting its life span.
Protein processing and degradation:
protein
complexes
called
degrade proteins by binding to proteins tagged by
and digesting them.
Overview:
Control of Gene Expression
Review:
Control of Gene Expression
Chapter
20
Quizzes:
Self
Activities
Chapter
Cum.
Videos
Movies
Words
Appendix
Summary
Art
Art
Unit 3: Genetics
DNA Technology and Genomics
Review
DNA
cloning
(making copies of a DNA segment) often makes use of a
bacterial
.
Bacterial
enzymes
can be used to make
DNA,
which can then be
cloned
and
stored
in genomic
libraries.
Clones carrying the gene of interest can be identified by
nucleic
acid
, using a radioactively labeled nucleic acid
.
The polymerase
reaction
(PCR)
can make
copies
of a segment of DNA in
.
Restriction fragment
can detect differences in DNA
by using
gel
electrophoresis
to
separate
restriction fragments of different lengths.
DNA fragments can also be identified by
Southern
and detected by
.
These technologies can be used as a
DNA
tool.
Sequencing, or
, entire
genomes
of an organisms, such as done in the Human
Project,
can be approached in three
stages.
Start with a rough map of some genes through techniques such as fluorescence in situ
(FISH).
Construct a
map
of several thousand genetic
spaced throughout each of the
based on
frequencies.
Construct a
map by cutting DNA into fragments and arranging them in order by identifying
overlaps.
Short DNA fragments can be sequenced by the
chain-termination
method.
An alternative approach starts with the
of random DNA fragments, and
assembling
the large number of overlapping sequences with computer software.
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