Exam 25: Microbial Symbioses

According to the free energy obtained from each product using CO2 and H2, methanogenesis is favored over acetogenesis. Why is this NOT the case in termites?

Both pathogenic bacteria and primary symbionts have a tendency to lose genes for catabolic pathways.

The function of leghemoglobin in root nodules is to

Two- thirds of terrestrial environments support growth of termites.

Describe where lichens can be found and which organisms are involved. Also detail how each benefit in the relationship.

_________are intracellular bacteria that are usually localized to specialized organs within their host.

What is the role of the vir genes on a Ti plasmid?

Certain species of Bacteria have been identified to cause obesity.

Several rhizobial species within a cross- inoculation group should be able to grow with particular legume species such as alfalfa, however the same cross- inoculation group would be unable to associate with other legumes species.

The mycelia of mycorrhizae can form underground nutrient networks where several trees are connected.

The mutualism of Azolla- Anabaena is useful for

During the Jurassic Period, several different mammalian lineages independently evolved a(n)_________ lifestyle for obtaining energy.

Provide an example of how an abrupt diet change in a rumen such as a cow can cause serious illnesses, even death. Also explain the processes that develop into sickness.

Microorganisms can associate with and benefit plants by increasing _________and defending against__________.

Which bacterium contains a large Ti plasmid and causes crown gall disease in plants?

Two organisms that both benefit from each other are in a symbiotic relationship called

Two main symbionts of termites are ________and _________.

Bacteroids are rarely found within plant cells.

The gut flora is relatively stable over long time periods in healthy adults, suggesting its "fine- tuned" role.

The primary site(s) of fiber breakdown mediated by microorganisms in cecal fermenters is/are________ , and the site(s) for hindgut fermenters is/are________ .