Week 10 Review (Chapter 11)

Several genera can form a resting stage or spores that allows them to survive the dry periods that occur in many soils. Select all the resting cells/structures from the list.

- Endospores (Bacillus and Clostridium ) - Conidia ( Streptomyces) - Microcysts ( myxobacteria )

Select the TRUE statements about obligate aerobes.

- Micrococcus species typically form colored colonies, making them easy to identify. Mycobacterium species have an unusual cell wall that requires special procedures for staining. - Deinococcus species can be extraordinarily resistant to the effects of gamma rays.

Which of the following about bacterial diversity are FALSE?

- Squid and flashlight fish have specialized organs that carry nitrogen-fixing bacteria - Agrobacterium species carry plasmids with genes for a toxin that destroys plant cells.

Which of the following are TRUE regarding purple sulfur bacteria, purple non-sulfur bacteria, and green sulfur bacteria?

- They are anoxygenic phototrophs. -They all use sunlight as an energy source.

Which of the following are TRUE regarding coliforms?

- They are facultative anaerobes - They are Gram-negative - They characteristically ferment lactose - They belong to the family Enterobacteriaceae - They are used as indicators of fecal pollution

Please identify all the characteristics of cyanobacteria.

- They are photosynthetic and generate oxygen - They are primary produce in the food chain - Many can convert nitrogen gas into organic compounds - They may form multicellular associations that glide

Which of the following statements about members of the genus Mycoplasma are true?

- They are unaffected by penicillins - they lack a peptidoglycan cell wall - They are difficult to filter from growth media

Oxygenic phototrophs

- generate O2. - are red or purple in color. - play a role in nitrogen fixation.

Identify which of the following genera have members that are disease-causing facultative anaerobes.

- Corynebacterium - Escherichia - Mycobacterium - Thermus

Select the TRUE statements about nitrifiers.

- They convert ammonium to nitrite - they convert nitrite to nitrate

Comprehension: Bacteria That Resist Effects of UV Light

1.) Consider your results and select the CORRECT statement. - UV radiation does not appear to affect the growth of D. radiodurans. 2.) Select the FALSE statement regarding D. radiodurans. - Members of this genus are obligate anaerobes. 3.) In your experiment, what is the control? - E. coli and D. radiodurans not exposed to UV at all (0 s). 4.) Which of the following is a potential future use of genetically engineered Deinococcus? - Deinococcus may be used to clean up environmental radioactive waste.

Select which of the following statements about Agrobacterium tumefaciens is FALSE.

A. tumefaciens causes a plant disease called "root gall" that is characterized by swollen nodules on the roots of plants.

A unicellular microorganism was recovered from a hot spring (95°C) in Wyoming. After observation, it was determined that the cells lacked a nucleus, had a cell wall that lacking peptidoglycan, and had 70S ribosomes. Analysis of the cytoplasmic membrane revealed lipids containing long-chained branched hydrocarbons with ether linkages. Determine how this organism would be classified, based on the description provided.

Archaea

Based on what you know about the myxobacteria, for which of the following could they serve as an experimental model?

Cell-to-cell communication and cooperation

Match the Clostridial species with the diseases they cause.

Clostridium botulinum - Botulism, a disease characterized by flaccid paralysis. Clostridium difficile - Antibiotic-associated diarrheal disease. Clostridium tetani - Tetanus: a disease characterized by painful muscle spasms. Clostridium perfringens - Gas gangrene: a disease characterized by necrotic tissue and the production of gas.

Match each of the following resting stages of microbes with their correct description.

Conidia - Formed by Gram-positive Streptomyces species at the tips of hyphae. Resistant to drying. Microcysts - Formed by Gram-negative myxobacterial fruiting bodies. Moderately resistant to heat, dessication, and radiation. Endospores - Formed by Gram-positive Bacillus and Clostridium species. Highly heat-resistant; also highly resistant to dessication (drying) and radiation.

Please match the anaerobic chemoorganotrophs with their description.

Lactic Acid Bacteria - Important in producing fermented foods. Lactobacillus Species - Common members of the mouth and vaginal normal microbiota. Propionibacterium species - Important in Swiss cheese production. Enterococcus species - Normal microbiota of the intestinal tract of humans and other animals. Clostridia - Cause of diseases such as tetanus and botulism.

Members of this group of microbes can break down glycogen deposited in the vaginal lining in response to estrogen. This helps to drop the pH in the area, preventing infections.

Lactic acid bacteria

Which of the statements about chemotrophs is FALSE?

Lactic acid bacteria such as Lactobacillus obtain their ATP by oxidizing glucose, using lactic acid as their terminal electron acceptor.

Bacteria in aquatic environments have evolved various mechanisms to maximize nutrient uptake and retention. Why?

Most aquatic environments lack a steady supply of nutrients.

Match each of the following anaerobic chemotrophs with their descriptions.

Propionibacterium species - Gram-positive pleomorphic (irregular shaped) rods, fermenters, often used in Swiss cheese production. Clostridium species - Generally in endospore form in soil, but will germinate to vegetative form when anaerobic conditions arise. Gram-positive rods. Methanogens - Archaea, live in anaerobic environments with H2 and CO2. Sulfur and sulfate-reducing bacteria - Found in mud with organic material and oxidized sulfur compounds. Lactic Acid bacteria - Gram-positive, catalase-negative, grow in aerobic environments but only ferment, producing acidic conditions.

Which of the statements is FALSE?

Rhizobia transfer some of their DNA to the host plant.

Match each of the following aerobic chemolithotrophs with their characteristics.

Sulfa-oxidizing bacteria - Gram-negative rods/spirals, may form filaments, obtain energy by oxidizing hydrogen sulfide and thiosulfate with O2 as a terminal electron acceptor. Nitrifying bacteria - Gram-negative bacteria that obtain energy by oxidizing inorganic compounds like ammonia. Hydrogen-Oxidizing Bacteria - Gram-negative obligate chemolithotrophs, use H2 as an energy source with O2 as a terminal electron acceptor.

Which of the following bacteria can oxidize metal compounds exposed during strip mining of coal, dramatically lowering pH and leading to damaging acid run-off into the surrounding ecosystem?

Sulfur-oxidizing bacteria

Members of the genus Mycoplasma have no cell wall, making them somewhat unique in the microbial world. How do they prevent osmotic lysis?

Their cytoplasmic membrane is rich in sterols to help provide added strength and rigidity.

Which is NOT a method used by cyanobacteria to protect their nitrogenase from oxygen?

They may isolate their nitrogenase into endospores that only germinate at night.

Select the TRUE statement regarding Agrobacterium species.

They stimulate tumor-like growths in plants to obtain nutrients.

The rhizobia group of microbes

form a nodule that creates an endosymbiotic relationship between legume plants and the bacterial cells.

A farmer would encourage the growth of Rhizobium species near certain plants because the rhizobia

produce a nitrogen source that can by used by the plant

Streptomyces

produce useful antibiotics.

Nitrogen-fixing cyanbacteria are important because

- they can incorporate N2 into organic material, thus generating a form that other organisms can use. - they can incorporate CO2 into organic material, thus generating a form that other organisms can use. -they help to limit CO2 buildup in the atmosphere, by using this gas as a carbon source.

Which of the following is NOT a member of the Enterobacteriaceae family (Gram-negative rods, glucose fermenters, some members motile with peritrichous flagella, some members lactose fermenting)?

Corynebacterium diphtheriae

Select the FALSE statement regarding bacterial diversity.

During unfavorable conditions, myxobacteria travel as a pack to a new location.

Match each extreme thermophile group with its description.

Methane-generating hyperthermophiles - Oxidize H2, using CO2 as a terminal electron acceptor to yield gas. Can grow in temperatures as high as 97°C. Thermophilic Extreme Acidophiles - Members grow optimally at or below pH 2. One was originally isolated from a coal waste pile. Two others were isolated inhabiting acidic areas in regions that spew sulfurous gases. Sulfur Oxidizers - Obligate aerobes that use O2 as a terminal electron acceptor, generating sulfuric acid. Only grow above 50°C and at a pH between 1 and 6. Nanoarchaea - Grows as 400 nm spheres attached to the surface of - and most likely parasitizing - the Ignicoccus species. Sulfur-reducing Hyperthermophiles - Obligate anaerobes that use sulfur as a terminal electron acceptor, generating H2S. Often isolated from hot sulfur-containing environments such as sulfur hot springs and hydrothermal vents. Some even have possible growth temperatures above 100°C.

Match each of the following obligate aerobic bacteria with its description.

Micrococcus Species - Gram-positive cocci found in soil, dust particles, inanimate objects, skin; tolerates dry and moderately salty conditions. Pseudomonas species - Gram-negative rods with polar flagella. Often produce pigments. Widespread in soil and water. Most are harmless, but some can be opportunistic pathogens of humans. Mycobacterium Species - Generally pleomorphic (variable shape) rods that stain poorly and resist destaining due to waxy lipids in their cell wall structure. Several species cause human diseases. Thermus species - Stain Gram-negative, but have an unusual cell wall. Survive well in high heat, due to their interesting heat-resistant enzymes. Deinococcus Species - Stain Gram-positive, with an odd multilayer cell wall that lets the cells resist high levels of gamma radiation (also due to their extensive DNA repair enzyme activities).

Please match members of the aerobic chemoorganotrophs with the diseases they cause.

Mycobacterium leprae - Hanson's disease (leprosy) Pseudomonas aeruginosa - Opportunistic diseases in hospitalized patients. Yersinia pestis - Bubonic and pneumonic plague. Vibrio cholerae - Gastrointestinal disease.

Methanogens are a group of archaea that generate ATP by

Oxidizing hydrogen gas, using carbon dioxide as a terminal electron acceptor