Question 1

Which habitats would be favored by thermoacidophiles?
A) The stomachs of many herbivores
B) Hot,alkaline springs
C) Anaerobic conditions
D) Hot sulfur springs
E) Deep-sea volcanic vents

Accepted Answer

Thermoacidophiles are organisms that require both high temperatures and acidic environments to survive. Hot sulfur springs, which are high in sulfur and other acidic compounds, would therefore provide an ideal habitat for these organisms. The other options may support other types of extremophiles, but not specifically thermoacidophiles.

Question 2

Suppose you are building an artificial hot spring in your yard.The water is hot and mineral-rich,but it doesn't have the bright colors seen in natural hot springs.To get those bright colors,you could allow the growth of
A) cyanobacteria.
B) mycoplasmas.
C) crenarchaeotes.
D) proteobacteria.
E) spirochetes.

Accepted Answer

The answer of Suppose you are building an artificial hot...

Question 3

_______ are small intracellular parasites that have a unique,complex reproductive cycle and include strains that cause eye infections and venereal disease.
A) Chlamydias
B) Spirochetes
C) Cyanobacteria
D) Proteobacteria
E) Actinobacteria

Accepted Answer

Chlamydias are small intracellular parasites that have a unique, complex reproductive cycle and include strains that cause eye infections and venereal disease. Spirochetes are spiral-shaped bacteria that include strains that cause syphilis and Lyme disease. Cyanobacteria are photosynthetic bacteria that often form colonies and can contribute to harmful algal blooms. Proteobacteria and Actinobacteria are broad categories of bacteria that include a diverse range of species with varying characteristics and functions.

Question 4

Which pair includes two members that involve DNA transfer by prokaryotes?
A) Lateral gene transfer and crown gall
B) Crown gall and virus formation
C) Lateral gene transfer and virus formation
D) Crown gall and biofilm formation
E) Biofilm formation and lateral gene transfer

Accepted Answer

Lateral gene transfer and crown gall both involve DNA transfer by prokaryotes. Lateral gene transfer is a process where prokaryotes exchange genetic material, and crown gall disease involves the transfer of DNA from the bacterium Agrobacterium tumefaciens to plant cells.

Question 5

Which characteristic or component is distinctive to archaea?
A) Unique genes not found in other domains
B) Branched,long-chain hydrocarbons
C) A lack of peptidoglycan
D) Lipids with glycerol-ether linkages
E) All of the above

Accepted Answer

Archaea are characterized by all of the following: unique genes not found in other domains, branched, long-chain hydrocarbons, a lack of peptidoglycan, and lipids with glycerol-ether linkages.

Question 6

_______,which include the bacterium that causes syphilis,use axial filaments to move.
A) Cyanobacteria
B) Spirochetes
C) Chlamydias
D) Proteobacteria
E) Actinobacteria

Accepted Answer

Spirochetes, such as the bacterium Treponema pallidum (which causes syphilis), use axial filaments (also known as endoflagella) to move. These filaments are located within the periplasmic space and rotate around the cell body, allowing the bacteria to move in a corkscrew-like motion.

Question 7

Spirochetes move via
A) gas vesicles.
B) cilia.
C) axial filaments.
D) pseudopods.
E) flagella.

Accepted Answer

Spirochetes move using axial filaments, which are also known as endoflagella. These structures are located in the periplasmic space and allow the spirochete to move in a corkscrew motion.

Question 8

Which statement about spirochetes is true?
A) They are all free-living.
B) They are all parasites of other bacteria.
C) They can form chains of cells.
D) They all possess structures called terminal filaments.
E) They are spiral-shaped bacteria.

Accepted Answer

Spirochetes are spiral-shaped bacteria.

Question 9

Actinobacteria
A) are photoheterotrophs.
B) are the only bacteria that divide by mitosis.
C) are Gram-negative bacteria.
D) were once classified as protists.
E) are the source of many important antibiotics.

Accepted Answer

Actinobacteria are known to produce numerous antibiotics such as streptomycin, erythromycin, and tetracycline.

Question 10

The size of the smallest bacterium is _______$\mu$m.
A) 0.2
B) 2
C) 7.5
D) 75
E) 750

Accepted Answer

The size of the smallest bacterium is around 0.2 micrometers, which is equivalent to 0.0002 mm. Options B, C, D, and E are all significantly larger than this size.

Question 11

Cyanobacteria
A) are a diverse and unrelated group of bacteria.
B) use chlorophyll a and release oxygen during photosynthesis.
C) are the only group of photosynthetic bacteria.
D) can reproduce sexually.
E) are obligate aerobes.

Accepted Answer

Cyanobacteria are a group of photosynthetic bacteria that use chlorophyll a and release oxygen during photosynthesis. They are not the only group of photosynthetic bacteria but are one of the most well-known. They are also known as blue-green algae, although they are not algae. Cyanobacteria do not reproduce sexually but can reproduce asexually. They are typically obligate aerobes, meaning they require oxygen to survive.

Question 12

The best place to look for a new,heat-tolerant DNA polymerase enzyme would be among the
A) thermophilic archaea.
B) methanogens.
C) extreme halophiles.
D) spirochetes.
E) proteobacteria.

Accepted Answer

Thermophilic archaea live in extreme environments with high temperatures and would therefore have evolved heat-tolerant enzymes, including DNA polymerases.

Question 13

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

Accepted Answer

Chlamydias are obligate intracellular pathogens, meaning they can only survive and reproduce within the cells of other organisms. They are not capable of living independently outside of a host cell.

Question 14

Which sequence represents the correct chronological order of events in the life of a Gram-positive bacterium?
A) Endospore formation,low-nutrient stress,endospore germination,breakdown of parent cell
B) Low-nutrient stress,endospore formation,breakdown of parent cell,endospore germination
C) Endospore formation,endospore germination,breakdown of parent cell,low-nutrient stress
D) Low-nutrient stress,endospore germination,breakdown of parent cell,endospore formation
E) Endospore germination,breakdown of parent cell,low-nutrient stress,endospore formation

Accepted Answer

Gram-positive bacteria form endospores in response to low-nutrient stress. Once the endospore is fully formed, the parent cell breaks down, and the endospore remains dormant until conditions improve. When conditions improve, the endospore germinates, and a new vegetative cell is formed. Therefore, the correct chronological order is low-nutrient stress, endospore formation, breakdown of parent cell, and endospore germination. Option B is the only one that follows this sequence.

Question 15

You are given a mixed sample of Bacteria and Archaea and asked to identify which more specific groups are present.When you try culturing portions of the sample under different conditions,freshwater cultures at room temperature turn blue-green and cultures in high salt become dark purple.Which groups must be present in the mixed sample?
A) Cyanobacteria and extreme halophiles
B) Extreme halophiles and proteobacteria
C) Proteobacteria and euryachaeota
D) Chlamydias and cyanobacteria
E) Chlamydias and proteobacteria

Accepted Answer

Blue-green pigment is typically indicative of photosynthetic pigments like chlorophyll found in Cyanobacteria, while dark purple pigment indicates the presence of bacteriorhodopsin-like pigments found in extreme halophiles. Therefore, the mixed sample must contain both Cyanobacteria and extreme halophiles.

Question 16

Which bacterial group includes the greatest number of species?
A) Chlamydia
B) Proteobacteria
C) Actinobacteria
D) Mycoplasmas
E) Cyanobacteria

Accepted Answer

Proteobacteria is the largest and most diverse bacterial group, which includes many well-known species, such as E. coli, Salmonella, and Vibrio cholerae.

Question 17

The chlorophyll of cyanobacteria is
A) bacteriorhodopsin.
B) distinct from the chlorophyll of plants.
C) bacteriochlorophyll.
D) like that of plants.
E) rarely produced.

Accepted Answer

Cyanobacteria contain chlorophyll a, which is similar to the chlorophyll found in plants, allowing them to perform photosynthesis.

Question 18

Which group of prokaryotes was responsible for converting Earth's early atmosphere from anaerobic to aerobic?
A) Proteobacteria
B) Halophiles
C) Cyanobacteria
D) Spirochetes
E) Actinobacteria

Accepted Answer

Cyanobacteria were responsible for the Great Oxygenation Event which occurred around 2.4 billion years ago and converted Earth's early atmosphere from anaerobic to aerobic by producing oxygen through photosynthesis. The other prokaryotic groups listed did not have a significant role in this process.

Question 19

_______ contain photosynthetic lamellae and photosynthesize using chlorophyll a.
A) Proteobacteria
B) Spirochetes
C) Chlamydias
D) Cyanobacteria
E) Firmicutes

Accepted Answer

Cyanobacteria are the only option that contain photosynthetic lamellae and use chlorophyll a for photosynthesis. Proteobacteria, Spirochetes, Chlamydias, and Firmicutes do not have these features.

Question 20

Some cyanobacteria that form filamentous colonies possess heterocysts,which are
A) a means of locomotion.
B) infectious.
C) the resting stage for the cyanobacteria.
D) endospores.
E) cells specialized for nitrogen fixation.

Accepted Answer

Heterocysts are specialized cells in cyanobacteria that are involved in nitrogen fixation. They are not a means of locomotion, infectious agents, resting stages, or endospores.

Quiz 19: Bacteria, Archaea, and Viruses

Which habitats would be favored by thermoacidophiles?

Suppose you are building an artificial hot spring in your yard.The water is hot and mineral-rich,but it doesn't have the bright colors seen in natural hot springs.To get those bright colors,you could allow the growth of

_______ are small intracellular parasites that have a unique,complex reproductive cycle and include strains that cause eye infections and venereal disease.

Which pair includes two members that involve DNA transfer by prokaryotes?

Which characteristic or component is distinctive to archaea?

_______,which include the bacterium that causes syphilis,use axial filaments to move.

Spirochetes move via

Which statement about spirochetes is true?

Actinobacteria

The size of the smallest bacterium is _______ $\mu$ m.

Cyanobacteria

The best place to look for a new,heat-tolerant DNA polymerase enzyme would be among the

Chlamydias

Which sequence represents the correct chronological order of events in the life of a Gram-positive bacterium?

Which bacterial group includes the greatest number of species?

The chlorophyll of cyanobacteria is

Which group of prokaryotes was responsible for converting Earth's early atmosphere from anaerobic to aerobic?

_______ contain photosynthetic lamellae and photosynthesize using chlorophyll a.

Some cyanobacteria that form filamentous colonies possess heterocysts,which are