Question 1

Which statement about hyperthermophilic bacteria is true?

Accepted Answer

A)  Their high metabolic rates create high temperatures. 
B)  Their metabolic rates speed up as the temperature drops. 
C)  They live in conditions that may resemble those of Earth's early environments. 
D)  They cannot tolerate high temperatures. 
E)  They lack properly folded proteins at high temperatures.

Question 2

Based on the phylogenetic relationship and genes shared by the lokiarchaeotes and eukaryotes, one might predict that

Accepted Answer

A)  lokiarchaeotes share similar cellular morphologies with certain eukaryotes. 
B)  lokiarchaeotes can tolerate high temperatures. 
C)  lokiarchaeote genomes primarily result from lateral gene transfer. 
D)  lokiarchaeotes and eukaryotes are capable of interbreeding. 
E)  lokiarchaeotes have arisen from eukaryotes.

Question 3

Refer to the figure, which shows the light absorption of a green alga and purple sulfur bacteria.  Based on the figure, which statement about the organisms or their chlorophyll is true?

Accepted Answer

A)  The chlorophyll found in purple sulfur bacteria absorbs light maximally at approximately 450 nm and 675 nm. 
B)  The chlorophyll found in purple sulfur bacteria absorbs light at the same wavelengths as that in the green alga. 
C)  Purple sulfur bacteria can absorb light at wavelengths not absorbed by green algae. 
D)  Maximum absorption of light in purple sulfur bacteria is the same as it is in green algae. 
E)  The chlorophyll found in the green alga absorbs light at approximately 375 nm and 875 nm.

Question 4

Which statement about cyanobacteria is false?

Accepted Answer

A)  Cyanobacterial colonies may form filaments. 
B)  Some filamentous cyanobacterial colonies differentiate to form heterocysts, which can survive harsh environmental conditions. 
C)  Some filamentous cyanobacterial colonies differentiate to form photosynthetic vegetative cells. 
D)  Some filamentous cyanobacterial colonies differentiate to form spores, which can survive harsh environmental conditions. 
E)  Cyanobacteria contain elaborate internal membrane systems called photosynthetic lamellae.

Question 5

Some archaea return significant quantities of organic carbon to the atmosphere as

Accepted Answer

A)  carbon monoxide. 
B)  carbon dioxide. 
C)  glucose. 
D)  methane. 
E)  nitrate.

Question 6

The earliest prokaryotic fossils date back at least _______ years.

Accepted Answer

A)  35,000 
B)  350,000 
C)  3.5 million 
D)  3.5 billion 
E)  3.5 trillion

Question 7

Refer to the figure, which shows the light absorption of a green alga and purple sulfur bacteria.  What can be concluded from these spectroscopy data?

Accepted Answer

A)  Purple sulfur bacteria use nitrogen as an electron acceptor. 
B)  Purple sulfur bacteria are able to grow under layers of the green alga. 
C)  The algae are entirely dependent on purple sulfur bacteria. 
D)  Bacteria do not contain bacteriochlorophyll. 
E)  Purple sulfur bacteria photosynthesize only in cloudy weather.

Question 8

Which statement about the biofilm found in the human large intestine is false?

Accepted Answer

A)  It is made up of numerous species of toxic bacteria. 
B)  It facilitates nutrient transfer from the intestine to the body. 
C)  It is essential for human health. 
D)  Its exact species makeup varies from region to region in the intestines. 
E)  Humans obtain vitamins B12 and K from the bacterial waste products.

Question 9

_______ are more closely related to _______ than they are to _______.

Accepted Answer

A)  Bacteria; prokaryotic archaea; eukaryotes 
B)  Bacteria; eukaryotes; prokaryotic archaea 
C)  Prokaryotic archaea; bacteria; eukaryotes 
D)  Eukaryotes; prokaryotic archaea; bacteria 
E)  Eukaryotes; bacteria; prokaryotic archaea

Question 10

Which statement about mycoplasmas is false?

Accepted Answer

A)  Their DNA codes for fewer than 500 proteins. 
B)  The amount of their DNA may be close to the minimum required by a living cell. 
C)  They lack a cell wall. 
D)  They are a valuable source of antibiotics. 
E)  They are among the smallest organisms known.

Question 11

Both eukaryotes and prokaryotes

Accepted Answer

A)  have membrane-enclosed organelles. 
B)  have a system for generating ATP. 
C)  have a nucleus. 
D)  have mitochondria. 
E)  undergo mitosis.

Question 12

Chlamydias

Accepted Answer

A)  can form heterocysts. 
B)  form branched, filamentous mycelia. 
C)  contain less DNA than any other type of organism. 
D)  can live only within the cells of other organisms. 
E)  were once classified as fungi.

Question 13

Which statement about bacteria is false?

Accepted Answer

A)  Some species live in our intestines, but none can exist in the highly acidic conditions of our stomachs. 
B)  Some species contribute to atmospheric greenhouse gases. 
C)  Some species live in conditions that may resemble those of early Earth environments. 
D)  Some species are able to use sunlight as a source of energy. 
E)  Some species can form endospores capable of enduring harsh conditions.

Question 14

A patient comes to your medical practice with a bacterial infection.You are terribly concerned because the bacteria responsible for the patient's infection produce an exotoxin.Why are exotoxins often more dangerous than endotoxins?

Accepted Answer

The answer of A patient comes to your medical practice...

Question 15

The common ancestor of life probably had

Accepted Answer

A)  membrane-bound organelles. 
B)  operons. 
C)  a Golgi apparatus. 
D)  a circular chromosome. 
E)  a nucleus.

Question 16

Spirochetes

Accepted Answer

A)  are all free-living. 
B)  are the only spiral-shaped bacteria. 
C)  can form chains of cells. 
D)  possess structures called axial filaments. 
E)  are all parasites of other bacteria.

Question 17

Biologists have hypothesized that high temperatures characterized the early conditions of life on Earth.Which statement would provide the best support for this hypothesis?

Accepted Answer

A)  Human intestinal microbial biota function best at temperatures near the boiling point of water. 
B)  Bacteria that normally live on human skin thrive at temperatures around 55°C. 
C)  Most eukaryotic species flourish at temperatures found in hot springs. 
D)  Reconstructions of ancestral bacterial genes show that the ancestral sequences functioned best at elevated temperatures. 
E)  The monophyly of the hyperthermophilic bacteria is well established.

Question 18

Which of the following bacterial groups includes the greatest number of known species?

Accepted Answer

A)  Chlamydias 
B)  Proteobacteria 
C)  Actinobacteria 
D)  Mycoplasmas 
E)  Cyanobacteria

Question 19

Because viruses have multiple evolutionary origins, they are considered to be a(n) _______ rather than a monophyletic group.

Accepted Answer

The answer of Because viruses have multiple evolutionary origins, they...

Question 20

The archaea that live in deep-sea hydrothermal vent ecosystems are

Accepted Answer

A)  photoautotrophs. 
B)  photoheterotrophs. 
C)  chemoautotrophs. 
D)  chemoheterotrophs. 
E)  nitrifiers.

Exam 25: Bacteria, Archaea, and Viruses