Chapter 11 Reading Assignment

Hydrogen-oxidizing bacteria such as Aquifex and Hydrogenobacter are ______.

thermophilic; obligate chemoplithotrophs; gram-negative

Bacteria that oxidize sulfur are Gram-negative rods or spirals that ______.

use sulfur compounds as an energy source and oxygen as a terminal electron acceptor

Cyanobacteria as a group are capable of ______.

both photosynthesis and nitrogen fixation

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

cyanobacteria

Unlike in other anoxygenic phototrophs, in purple bacteria, the components of the photosynthetic apparatus are all located in the cell's _____________ membrane.

cytoplasmic

The purple bacteria are Gram-negative organisms that can appear ______ due to their light-harvesting pigments.

purple; orange; red

Like the green and purple bacteria, members of the genus Heliobacterium are also examples of anoxygenic phototrophs. They are ______ bacteria related to members of the genus Clostridium.

endosproe-forming; rod-shaped; gram-positive

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

respiration

An anaerobic chemoorganotroph that uses glucose for energy and pyruvate as its terminal electron acceptor is performing ______.

fermentation

A group of bacteria called green bacteria are ______.

gram-negative

True or False: Through both traditional and new molecular techniques, scientists have now identified most existing microbial species.

False

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

Members of the Gram-negative genera Aquifex and Hydrogenobacter are hydrogen-oxidizing bacteria. An example of their metabolism involves using ______.

hydrogen as a source of energy and oxygen as a terminal electron acceptor, forming water

Chemoorganotrophs oxidize ____________ compounds such as glucose to obtain energy.

organic

Aerobic chemoorganotrophs gain energy via the ______________, using O2 as a terminal electron acceptor.

oxidation of organic compounds

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

water

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

O2- consuming organisms depletes the oxygen levels

As a group, anaerobic chemoorganotrophs ____.

Produce ATP via substrate level phosphorylation; can obtain energy via fermentation

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

O2

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

skin, intestinal tract, sterile body fluids, oral cavity

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

H2S (hydrogen sulfide)

As a group, chemolithotrophs ______ to obtain energy.

by oxidizing inorganic chemicals such as hydrogen gas

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

nitrogen fixation

True or False: We are only now beginning to understand the diversity of prokaryotes.

True

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

aerobic chemolithotrophs

Chemoorganotrophs that perform ______ often use sulfur or sulfate as a terminal electron acceptor.

anaerobic respiration

Which of the following were likely the earliest photosynthesizing organisms? Multiple choice question.

anoxygenic phototrophs

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

archaea

The green bacteria are Gram- _________ organisms that are typically green or brownish in color.

negative

The green bacteria are Gram-_______ organisms that are typically green or brownish in color.

negative

A diverse group of Gram-negative bacteria that obtain energy by oxidizing inorganic nitrogen compounds such as ammonium or nitrate are known as ____________.

nitrifiers

Like the green and purple bacteria, members of the genus Heliobacterium are also examples of anoxygenic phototrophs. They are ______ bacteria related to members of the genus Clostridium.

gram-positive; rod-shaped; endospore-forming

Aside from green and purple bacteria, Gram-positive endospore forming rods of the genus ______ are also anoxygenic phototrophs.

heliobacterium