Chapter 11 MBIO

Bifidobacterium include the

GI tract (breastfed babies)

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

O2-consuming organisms depletes the oxygen levels

New _____________ ________________aiding in discovery, characterization

molecular techniques

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

swarmer

Only __________ of estimated million species of prokaryotes described and _________ genera

6,000 950

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

What bacteria forms chains of cells within a tube?

Sheathed bacteria

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

Thermoplasma and Picrophilus

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

Campylobacter jejuni infections are commonly associated with ______.

diarrhea

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

endospore

Prosthecate bacteria have

extensions that provide increased surface area for nutrient absorption, some allow attachment Caulobacter

Bacteriodes include the

mouth, GI and gential tracts

____________ 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

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

H2S

What are the differences to domain bacteria?

No peptidoglycan in cell wall. Thrive in extreme environments (high heat, acidity, alkalinity, salinity Methanogens are exception

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

O2

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

Rhizobium

Which of the following were likely the earliest photosynthesizing organisms?

anoxygenic phototrophs

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

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

cyanobacteria

All living things classified in _______.

domains

Extreme thermophiles are found near ______.

hot springs volcanic vents hydrothermal vents

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

nitrogen fixation

As a group, chemolithotrophs ______ to obtain energy.

oxidize reduced inorganic chemicals such as hydrogen gas

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

The three domains are _______, ________, ________.

Bacteria, Archaea, Eukarya

What are characteristics of domain bacteria?

Most common type in human infection Members widely diverse Single-celled, rod shaped, spherical, and spiral Rigid cell wall made of peptidoglycan Multiply by binary division Some bacteria are motile (move by flagella)

Facultative anaerobes preferentially use aerobic respiration if ______ is present.

O2

Mucous membrance include:

Respiratory, genitourinary, intestinal tracts

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

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

What are the similarities to domain bacteria?

Same shapes Multiple though binary fission Moves by means of flagellum

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

They fix nitrogen that can be used by the plant.

Organisms that form storage granules include ______.

Thiomargarita Spirillum Thioploca

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

Ti or tumor inducing

Anoxygenic phototrophs typically live in which of the following environments?

Upper layers of mud Bogs Lakes

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

Water

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

archaea; H2

Bdellovibrio species ______.

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

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

bioluminescent

Cyanobacteria as a group are capable of _

both photosynthesis and nitrogen fixation

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

cyanobacteria; nitrogen fixation

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

endospores

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

facilitate absorption of nutrients

An organism that cannot reproduce outside of a host cell is termed an __________ ___________parasite.

obligate intracellular

Methanogens are organisms that ______.

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

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

propionic acid; CO2

Staphylococcus epidermidis is part of the normal microbiota of the __________.

skin

Aquatic environments have gram negative ___________ ___________

sphaerotilus leptothrinx

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

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

fermentation

Humans infected with Helicobacter pylori may develop peptic

ulcers

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

ammonia

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

archaea

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

Aerobic chemolithotrophs

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

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

Bacteria and Archaea are

All single-celled organisms Contain no nucleus or any membrane-bound organelles Cytoplasm surrounded by rigid cell wall

___________ environments lack steady nutrient supply.

Aquatic

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

Archaea

Thermophilic extreme acidophiles ______.

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

Prokaryotes that grows well in an environment that contains 32% NaCl and found in salty environments would be called extreme

halophiles

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

nutrients

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

prokaryotes

Microbes live in _________ , _________, ________, and _________ environments.

Extreme, terrestrial, aquatic associations with plants, animals, insects

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

Prokaryotes are metabolically diverse meaning they have the ability to ___________________________________________ and allows ______________________.

use different substances as carbon and energy sources microbes to live in diverse environments