Question 19
Compare and contrast viral, prokaryotic
and eukaryotic genomes, and describe some mechanisms by which gene expression
is regulated in each cell type. [Chapters 18 and 19]
The Genetics of
Viruses (read pages 328-331)
Researchers
discovered viruses by studying a plant disease.
A virus is a genome
enclosed in a protective coat.
Viruses
can reproduce only within a host cell.
Phages
reproduce using lytic or lysogeneic cycles.
Animal
viruses are diverse in their modes of infection and replication.
Plant
viruses are serious agricultural pests.
Viroids
and prions are infectious agents even simpler than viruses.
Viruses
may have evolved from other mobile genetic elements.
The Genetics of
Bacteria (read pages 340-351)
The
short generation span of bacteria helps them adapt to changing environments.
Genetic
recombination produces new bacterial strains.
The
control of gene expression enables individual bacteria to adjust their
metabolism to environmental change.
Genome
Organization at the DNA Level (pages 357-362)
Repetitive
DNA and other noncoding sequences account for much of a eukaryotic genome.
Gene
families have evolved by duplication of ancestral genes.
Gene
amplification, loss or rearrangement can alter a cell’s genome during an organism’s
lifetime.
The Control of
Gene Expression (read pages 362-368)
Each
cell of a multicelluar eukaryote expresses only a small fraction of its genes.
The
control of gene expression can occur at any step in the pathway from gene to
functional protein.
Chromatin
modifications affect the availability of genes for transcription.
Transcription
initiation is controlled by proteins that interact with DNA and with each
other.
Post-transcriptional
mechanisms play supporting roles in the control of gene expression.
The Molecular
Biology of Cancer (read pages 369 to 372)
Cancer
results from genetic changes that affect the cell cycle.
Onocogene
proteins and faulty tumor-suppressor proteins interfere with normal signaling
pathways.
Multiple mutations underlie the development of cancer.
|
John C. Murphy |
Science |
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Phone: (815) 436-3200, ext. 2120 |
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jmurphy@learningcommunity202.org |
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© 2001 Plainfield Community Consolidated School District 202.