Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chap 23 - symbioses
Microbial Symbioses with Microbes, Plants, and Animals
| Question | Answer |
|---|---|
| what is a symbioses | a microbe that lives with a macroorganism or other microorganisms in long-term relationships |
| Symbioses relationships are ___________________ where the interactions benefit both organisms involved | mutualistic |
| most microorganisms in symbiotic relationships have coevolved meaning | the organisms have evolved together over time |
| what are lichens | leafy or encrusted organisms, formed between the relationship between a fungus and algae (cyanobacterium) |
| where are lichens most commonly found | bare rocks, tree trunks, house roofs, and the surfaces of bare soils |
| in lichens, what is the benefit of algea | photosynthetic and produces organic matter; algae can also fix nitrogen |
| in lichens, what does fungus provide | structure within the phototrophic partner, allows the cyanobacterium to grow protected from erosion and with dissolved inorganic nutrients |
| what is consortia? What is their "scientific" name? | microbial mutualisms in freshwater, called Chlorochromatium aggregatum |
| Chlorochromatium aggregatum is a mutualist relatioidic lakesnship between | Green sulfur bacteria (epibionts) and flagellated rod-shaped bacteriu, |
| what habitat is consortia normally found in | stratified sulfuridic lakes |
| describe the metabolism of epibionts | obligate anaerobic phototrophs |
| in stratified sulfuridic lakes, epibionts take up ____________________% of the bacterial biomass | 70% |
| explain the discovery of consortia | they were discovered over 100 years ago but the details were unknown until modern culture methods and molecular techniques allowed for more detailed studies |
| what creates root nodules | mutualistic relationships between legumes and nitrogen0fixing bacteria |
| what are the most important symbioses known | root nodule symbioses (between legumes and nitrogen fixing) |
| give some examples of leguemes | soybeans, clover, alfalfa, beans, peas, peanuts |
| what is the best known bacteria in the root nodule symbiosis | rhizobia |
| describe the metabolism of rhizobia | nitrogen-fixing |
| what class(es) is Rhizodia part of | Alphaproteobacteria or Betaproteobacteria |
| what is the importance of root nodule formation | significant increases in soil nitrogen levels, and accounts for 1/4 of Nitrogen fixed annually on earth |
| root nodules grow well in areas where | other plants do not (i.e. nitrogen deficient soils) |
| Nitrogen-fixing bacteria need __________ to generate energy for fixing Nitrogen | Oxygen (O2) |
| the enzymes that fix nitrogen are called _____________ and are inactivated by ______________ | nitrogenases; Oxygen (O2) |
| because the nitrogenase enzyme is inactivated by oxygen molecules; this protein serves as an "oxygen buffer" in root nodules | leghemoglobin |
| (not a question) different rhizobial species infect different species of legumes, so the bacteria that infect peas will be different from those that infect clover | |
| a cross-inoculation group is | a group of related legumes that can be infected by a particular species of rhizobia |
| after infecting a root to form a nodule, the bacteria change shapt and are called ______________ that form a ____________ in the nodule | bacteriods; symbiosome |
| what bacterial genes direct the steps in nodule formation | nod genes |
| the ______________ gene encodes proteins that produce olidosaccharides called _______________ | nodABC; Nod factors |
| what are the functions of Nod factors | induce root hair curling, trigger plant cell dividion, signal legumes to develop root nodule |
| ___________________ is a positive regulator that is induced by plant flavonoids (colored plant nutrients) | NodD |
| in root nodules, what do the plants provide for bacteriods | fuel in the form of pyruvate for nitrogen fixation |
| the legume-bacteria symbiosis is characterized by | oxygen sequestration, several metabolic reactions, and nutrient exchange |
| what are stem-nodules | nodules that are formed on the stem of plants |
| stem-nodules formation is more common in _________________ regions | tropical; where soil is depleted of nutrients and poor in nitrogen due to leaching |
| (not a question) nonlegume nitrogen-fixing symbiosis also occurs, but with bacteria other than rhizobia | |
| in the water fern _________________ contains a species of heterocyctous nitrogen fixing bacteria known as ________________ | Azolla; Anabaena |
| the alder tree (genus __________) has nitrogen-fixing root nodules that harbor the bacterium ________________ in the heterocyst-like structures that are protected from free oxygen | Alnus; Frankia |
| mycorrhizae is a mutualistic association of ___________________________ | plant roots and fungi |
| in mycorrhizae, the plant benefits from | the transfer of inorganic nutrients from the fungus |
| in mycorrhizae, the fungi benefits from the plant | the plant donates carbohydrates to the fungus |
| ectomycorrhizae | mycorrhizae remains outside the root; the fungi cells form a sheath around the outside of the root with little penetration |
| where would ectomycorrhizae be mostly found | forest trees, particularly boreal and temperate forests |
| endomycorrhizae | the mycelium of fungi becomes deeply embedded within the root tissue |
| arbuscular mycorrhizae | the name of the deeply embedded mycelium in roots |
| (ecto/endo)mycorrhizae is more common | ENDomycorrizae is more common |
| >80% terrestrial plant species have this specific form of mutualist relationship | Endomycorrhizae with fungi |
| how does mycorrhizal fungi assist plants | improve nutrient absorption; due to greater surface area provided by the fungal mycelium. this helps with plant growth |
| this species forms a parasitic symbiosis with plants and causes clown gall disease | Agrobacterium tumefaciens |
| what are crown galls | plant tumors produced by A. tumefaciens cells harboring large plasmids (Tumor induction plasmids) |
| to initiate tumor formation ... | the A. tumefaciens cells attach to a wound site on the plant |
| after A. tumefaciens attach to a plant | they synthesize cellulose microfibrils and transfer a portion of the Ti plasmid to plant cells |
| the DNA transfer of Ti cells is mediated by | vir-encoded protiens |
| what are some functional uses for the Ti plasmid in the laboratory | for genetic engineering of plants |
| for insects, microbial symbionts can be acquired in two ways _________________ | horizontal transmitting (from the environment) or vertical/heritable transmitting (parent to child) |
| in heritable symbionts, insects are ____________ (meaning that they lack a free-living replicative stage) | obligateand protection from pathogens |
| ___________________________ are required for the host to reproduce | Primary symbionts |
| characteristics of Secondary Symbionts | not required for reproduction, not always present in every individual, can invade different cells and live extracellularly, must provide a benefit |
| what type of benefit do secondary symbionts provide for insects | nutritional benefits, protection from environment, |
| what do parasitic symbionts do to infected insects | manipulate host's reproductive tissue |
| white flies infected with Rickettsia | produce twice the number of offspring compared to uninfected flies |
| the sperm of Wlbachia-infected male flies | can sterilize the uninfected females |
| purpose of termites | decompose cellulose and hemcellulose |
| termites are classified as _______________ or _______________ based on phylogeny | higher or lower |
| name the three parts of the termite gut | foregut, midgut, and hind gut |
| describe the posterior alimentary tract of higher termites | diverse community or anaerobes, including cellulolytic anaerobes, capable of digesting cellulose |
| describe the inhabitants of the alimentary tract of the lower termites | full of anaerobic bacteria and cellulolytic protists |
| Hawaiian Bobtail Squid has a mutualist relationship with | Aliivibrio fischeri |
| the hawaiian Bobtail Squit harbors large populations of bioluminescent A. fischeri in | a specialized (light organ) structure; which emits light that resembles moonlight penetrating marine waters |
| how does the hawaiian bobtail squid benefit from its mutualist relationship | camouflage from predators |
| (not a question) the symbiotic relationship between the hawaiian bobtail squid and A. fischeri is highly specific | |
| transmittion of A fischeri to hawaiian bobtain squid is | horizontal and shortly after juvenile squids hatch |
| bioluminescence of hawaiian bobtail squid is controlled by | quorum sensing |
| what is quorum sensing | the bacteria's ability to assess their environment for adequately numbers of them trying to carry out some collective activity |
| how do the A. fischeri benefit from the squid | supplied by nutrients from squid |
| hydrothermal vents support thriving communities that are fueled by ________________________ microbes | chemolithotrophic |
| how do chemolithotrophs obtain energy | from chemicals and electrons from inorganic compounds |
| a divers invertebrate community develops near ________________________ in the deep sea | hydrothermal vents |
| where do large tube worms, clams, and mussels develop | deep-sea hydrothermal vents |
| describe the mutualist (symbiotic) relationships at hydrothermal vents | chemoliithotrophic prokaryotes and vent invertebrates |
| veent tube worms form endocymbiont relationships with | trophsome, which are specialized hemoglobins responsible for high blood CO2 content |
| in deep sea hydrothermal vents, bacterial symbionts provide | nutrition (organic compounds) needed for host metabolism |
| in deep sea hydrothermal vents, host symbionts provide | sheltered microhabitat for microbes |
| what is a cold steep | an area of the ocean floor where H2S, CH4 and other hydrocarbon-rich fluid seepage occurs |
| endopathogenic | insect killing |
| endopathogenic nematodes | found nearly worldwide and infect a wide range of insect hosts |
| Photorhabdus and Xenorhabdus | Gram-negative bacteria, brimary bacteria symbionts of entomopathic nematodes |
| ____________________ studies have shown an association between bacterial and nematod species is very specific | Ribosomal |
| (not a question) coral skeleton very efficient light-gathering structure | |
| coral skeleton harbors __________________________ symbionts including cyanobacteria, rhodophytes, chlorophytes, dinoflagellates, and diatomes | phototropic |
Created by:
kandriot
Popular Biochemistry sets