Ch. 27

Some bacteria avoid a host's immune system by means of:

cloaking the cell with a watery capsule

Extrachromosomal circles of DNA in bacteria called _____ often carry genes involved in ____:

plasmids, antibiotic resistance

the structure in the accompanying figure labeled C (outermost layer) is ____, and the structure indicated by the letter I is _____.

C- the capsule, I- the flagella

what makes rRNA (or another sequence) a good 'evolutionary chronometer'?

all of the above

Once they appeared on Earth, ____ forever changed the atmosphere on earth by the production of large quantities of oxygen gas.

cyanobacteria

organisms that share the most DNA homology to mitochondria and chloroplasts, respectively, are:

proteobacteria, cyanoacteria

Which of the following groups of prokaryotes in the figure above contains the bacteria Helicobacter pylori, responsible for the human ulcers, and E. coli, beneficial intestinal bacteria in humans?

Proteobacteria

Prokaryotes found inhabiting the Great Salt Lake would be the ____

extreme halophiles

Which of the following groups of prokaryotes contain the genus Clostridium, responsible for the human diseases tetanus and botulism?

Gram positive eubacteria

Which of the following groups of prokaryotes might be found in the Great Salt Lake, the Red Sea, the Dead Sea, but NOT necessarily in the ocean?

extreme halophiles

The ____ Archaebacteria are typically found in extremely hot environments, whereas the _____ Archaebacteria are typically found in swampy environments lacking oxygen.

extreme thermophile, methanogenic

Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on:

infoldings of the plasma membrane

SELECT ALL THAT APPLY: which of the following cellular structures are shared by bacteria, archaea, and eukaryotes?

plasma membrane

Gram-positive bacteria stain _____ in a gram stain because of a thick layer of ____ in their cell walls

purple; peptidoglycan

The first indication that Archaea were different form the Eubacteria came from:

the absence of peptidoglycans in the cell walls of the Archaea

The most significant difference between the Archaea and the Eubacteria is:

the small subunit (16s) rRNA sequence

What is the function of the structures labeled B?

to adhere to host cells, to transmit DNA, to exchange genetic material

Most bacterial cells keep from bursting in a hypotonic environment by

a rigid cell wall

Many Gram (+) Eubacteria like Clostridium botulinum and Bacillus anthraxis have the ability to survive harsh environmental conditions by protecting their DNA in a dormant structure called a(n)

endospore