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 lysogenic cycles. Animal viruses are diverse in their modes of infection adn replication. Plant viruses are serious agricultural pests. Viroids and prions are infectious agents even simpler than viruses. Viruses may have evolved form other mobile genetic elements. The short generation span of bacteria helps them adapt to changin environments. genetic recombination produces new bacterial strains. The control of gene expression enables individual bacteria to adjust their metabolism to environmental change. Bacteria and archae are the two main branches of prokaryote evolution. Nearly all prokaryotes have a cell wall external to the plasma membrane. Many prokaryotes are motile. The cellular and genomic organization of prokaryotes is fundamentallly different form that of eukaryotes. populations of prokaryotes grow and adapt rapidly. Prokaryotes can be grouped into four categories according to how they obtain energy and carbon. Photosynthesis evolved early in prokaryotic life. Moleculer systematics is leading to a phylogenic classification of prokaryotes. researchers are identifying a great diversity or archae in extreme environments andin the oceans. Prokaryotes are indispensible links in the recycling of chmical elementsin the ecosystems. many prokaryotes are symbiotic. Pathogenic prokaryotes cause many human diseases. Humans use prokaryotes in research adn technology. Systemists have split protists into many kingdoms. Protists are the most diverse of all eukaryotes. Endomembranes contributed to larger, more complex cells. Mitorchondria and plastids evolved from endosymbiotic bacteria. the eukaryotic cell is a chimera of prokaryotic ancestors. secondary endosymbiosis increased the diversity of algae. Absorptive nutrition enable fungi to live as decomposers and symbionts. extensive surface area and rapid growth adapt fungi for absorptive nutrition. Fungi disperse and reproduce by releasing spores that are produced either sexually or asexually. many fungi have a heterokaryotic stage. ecosystems depend on fungi as decomposers and symbionts. Some fungi are pathogens. Fungi are commercially important. They colonize land with plants. Fungi and animals evolved from a common protistan ancestor.
Saturday, January 21, 2012
Diversity of Cells
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 lysogenic cycles. Animal viruses are diverse in their modes of infection adn replication. Plant viruses are serious agricultural pests. Viroids and prions are infectious agents even simpler than viruses. Viruses may have evolved form other mobile genetic elements. The short generation span of bacteria helps them adapt to changin environments. genetic recombination produces new bacterial strains. The control of gene expression enables individual bacteria to adjust their metabolism to environmental change. Bacteria and archae are the two main branches of prokaryote evolution. Nearly all prokaryotes have a cell wall external to the plasma membrane. Many prokaryotes are motile. The cellular and genomic organization of prokaryotes is fundamentallly different form that of eukaryotes. populations of prokaryotes grow and adapt rapidly. Prokaryotes can be grouped into four categories according to how they obtain energy and carbon. Photosynthesis evolved early in prokaryotic life. Moleculer systematics is leading to a phylogenic classification of prokaryotes. researchers are identifying a great diversity or archae in extreme environments andin the oceans. Prokaryotes are indispensible links in the recycling of chmical elementsin the ecosystems. many prokaryotes are symbiotic. Pathogenic prokaryotes cause many human diseases. Humans use prokaryotes in research adn technology. Systemists have split protists into many kingdoms. Protists are the most diverse of all eukaryotes. Endomembranes contributed to larger, more complex cells. Mitorchondria and plastids evolved from endosymbiotic bacteria. the eukaryotic cell is a chimera of prokaryotic ancestors. secondary endosymbiosis increased the diversity of algae. Absorptive nutrition enable fungi to live as decomposers and symbionts. extensive surface area and rapid growth adapt fungi for absorptive nutrition. Fungi disperse and reproduce by releasing spores that are produced either sexually or asexually. many fungi have a heterokaryotic stage. ecosystems depend on fungi as decomposers and symbionts. Some fungi are pathogens. Fungi are commercially important. They colonize land with plants. Fungi and animals evolved from a common protistan ancestor.
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