MICRO- CH 11: The Diversity of Bacteria and Archea

Extreme thermophiles are found near ______.

hot springs hydrothermal vents volcanic vents

As a group, chemolithotrophs ______ to obtain energy.

oxidize reduced inorganic chemicals such as hydrogen gas

Bioluminescent bacteria are characterized by ______.

the ability to emit light

True or false: Scientists now understand the true diversity of microbial life and have determined the relationships between the millions of prokaryotes that exist.

False

During photosynthesis, anoxygenic phototrophs use _______ as a source of electrons to make reducing power.

H2S

Aerobic chemolithotrophs obtain energy by oxidizing reduced inorganic chemicals, using ___ as a terminal electron acceptor.

O2

_______ are archaea that grow in extremely acidic and hot environments.

Thermoplasma and Picrophilus

Organisms that form storage granules include ______.

Thiomargarita Spirillum Thioploca

Which of the following were likely the earliest photosynthesizing organisms?

anoxygenic phototrophs

Bdellovibrio species ______.

prey on Gram negative bacteria like E. coli bore a hole in the cell wall of their prey are highly motile Gram-negative curved rods

Cyanobacteria as a group are capable of ______.

both photosynthesis and nitrogen fixation

In this micrograph of stained bacterial cells, the structures forming in the mid-portion of the cells are called ___

endospores

Of the various types of dormant cells, the ______ is the most resistant to environmental extremes.

endospores

Campylobacter jejuni infections are commonly associated with ______.

Diarrhea

An organism that cannot reproduce outside of a host cell is termed an ___ ____ parasite.

obligate intracellular

Nitrogen fixation, or the process of converting nitrogen gas (N2) into ammonia, is an exclusive ability of ______.

prokaryotes

The ____ bacteria have projections called prosthecae, which are extensions of the cytoplasm and cell wall that increase the surface area to facilitate absorption of nutrients.

prosthecate

The purpose of the sheath in sheathed bacteria is for ______.

protection

By definition, obligate intracellular parasites cannot ______.

replicate outside of a host cell

Obligate aerobes obtain energy using ____ exclusively; none of them can ferment.

respiration

How do obligate aerobes obtain energy?

using respiration only

Oxygenic phototrophs use ______ as a source of electrons for reducing power, generating O2.

water

Characterized members of the domain ______ typically thrive in extreme environments, such as high heat, acidity, alkalinity, and salinity.

Archaea

Certain bacteria that form symbiotic relationships with specific types of fish and squid are ______, meaning they emit light.

Bioluminescent

Facultative anaerobes preferentially use aerobic respiration if ___ is present.

O2

When undergoing photosynthesis, anoxygenic phototrophs use hydrogen sulfide or organic compounds as a source of electrons to make reducing power. Thus, they do not generate ______.

O2

A reason why environments that are routinely exposed to O2 can support anaerobic growth is that ______.

O2-consuming organisms depletes the oxygen levels

Members of which bacterial genus are used to make Swiss cheese?

Propionibacterium

A key characteristic of the genus Mycoplasma is that they lack a ____ ____, instead usually relying on sterols in their membrane to provide strength and rigidity.

cell wall

Streptomyces species naturally produce a wide array of medically useful chemicals that are used to treat microbial infections. These chemicals are referred to as

antibiotics

An organism found in an environment that is very hot and acidic is most likely a member of the domain

archaea

Heterocysts are structures found in ______ and are involved in _______.

cyanobacteria; nitrogen fixation

Prosthecate bacteria form projections called prosthecae, which are extensions of the cytoplasm and cell wall. These prosthecae ______.

facilitate absorption of nutrients

Facultative anaerobes can use aerobic respiration if O2 is present and ___ if O2 is not available.

ferment

An organism that requires a minimum of 9% NaCl would be called an extreme ______.

halophile

Prokaryotes that grow well in an environment that contains 32% NaCl would be called extreme

halophiles

Methanogens are organisms that ______.

obtain energy by oxidizing hydrogen gas use CO2 as a terminal electron acceptor generate methane

Methanogens are a group of _______ that produce methane by oxidizing _______.

archaea; H2

Antibiotics that interfere with peptidoglycan synthesis are ineffective in the treatment of _______ infections because these organisms lack a cell wall.

Mycoplasma

Which of the following explains the relationship between plants and their rhizobial endosymbionts?

Plants produce leghemoglobin, which binds to and keeps the levels of O2 low. Rhizobia fix nitrogen while residing inside plant cells.

Which of the following genera of organisms forms a beneficial symbiotic relationship with plants?

Rhizobium

The earliest oxygenic phototrophs probably belonged to a group of bacteria called the _____

cyanobacteria

Many cyanobacteria can convert nitrogen gas (N2) to ammonia, which is a process called ______.

nitrogen fixation

Humans infected with Helicobacter pylori may develop peptic ___

ulcers

The characteristic flavor and holes of Swiss cheese are caused by the fermentation products _______ and _______, respectively.

propionic acid; CO2

The purpose of storage granules produced by some bacteria is to store ______.

nutrients

Which of the following correctly describe relationships between genera of bacteria and their means for obtaining nutrients from plants?

Rhizobium species form a mutually beneficial relationship with certain types of plants. Agrobacterium species are plant pathogens that cause tumor-like growths.

Which of the following bacteria is typically a harmless resident of the skin?

Staphylococcus epidermidis

The genus _______ is a major producer of antibiotics, including tetracycline and erythromycin.

Streptomyces

What benefit do rhizobia provide the plants cells in which they reside?

They fix nitrogen that can be used by the plant.

The plasmid of Agrobacterium tumefaciens that allows the bacterium to induce plants to form tumors is called the ___ plasmid.

Ti

Anoxygenic phototrophs typically live in which of the following environments?

Upper layers of mud Lakes Bogs

Which of the following statements about microbial diversity is true?

We are only now beginning to understand the diversity of prokaryotes.

Thermophilic extreme acidophiles ______.

include members of the genera Thermoplasma and Picrophilus grow optimally at pH 2 or less

In a healthy individual, anaerobes can regularly be found on and in the ______.

intestinal tract oral cavity skin

Staphylococcus epidermidis is part of the normal microbiota of the ____

skin

The motile cells found in sheathed bacteria are called ______ cells, and these exit through the end of the sheath.

swarmer

Members of the genus Agrobacterium attach to a wounded plant and transfer a portion of their DNA to the plant cell, causing the plant to ______.

synthesize opine as a nutrient source for Agrobacterium form a tumor

Scientists are interested in studying the growth of extreme _____, archaea that grow near volcanic vents and fissures because these conditions are thought to mimic early earth's environment.

thermophiles

_______ gain energy via the oxidation of reduced inorganic chemicals, using O2 as a terminal electron acceptor.

Aerobic chemolithotrophs

In addition to being photosynthetic, many cyanobacteria have the ability to convert nitrogen gas (N2) into ______, a process known as nitrogen fixation.

Ammonia

____ species are Gram-negative curved rods that are highly motile and prey on other Gram-negative rods by boring a hole in their cell wall.

Bdellovibrio

Most of the anaerobic chemolithotrophs that have been discovered are members of what domain?

archaea