Deck 32: Microbial Interactions

Question 1

__________ enzymes catalyze the hydrolysis of beta (1-4)linkages between successive D-glucose residues of cellulose.

Answer 1

Cellulase

Question 2

A relationship in which one organism is found on the surface of another is referred to as a(n)___________.

Answer 2

ectosymbiosis

Question 3

When two different microbes are engaged in a cooperative relationship,they do as well when living separately as they do when living together.

Answer 3

False

Question 4

In commensalism

A)the host and commensal can be separated and remain viable.
B)the commensal is metabolically dependent on the host.
C)the host provides some factor that the commensal cannot get otherwise.
D)the host and commensal cannot be separated and remain viable and the commensal is metabolically dependent on the host.
E)all of these.

Question 5

The loss of genetic information no longer needed for an intracellular existence by an obligate parasite is called genomic _____________.

Question 6

In the host-parasite relationship,it is advantageous for the parasite to disable and kill its host as quickly as possible.

Question 7

Insects frequently contain bacteria in their cytoplasm,and these bacteria form a mutualistic association with their host.

Question 8

____________ is a beneficial relationship similar to mutualism,in which the relationship is not obligatory.

Question 9

Coral bleaching where the photosynthetic endosymbiont is lost or becomes non-functional can be caused by temperature increases as small as 2^oC.

Question 10

In a lichen,the fungal partner

A)protects the alga from excess light intensities.
B)provides water and minerals to the alga.
C)provides a substratum within which the alga grows.
D)all of these

Question 11

The term ____________ is used to describe a mutually beneficial association in which the growth of an organism is dependent on one or more growth factors,nutrients,or substrates provided by another organism in the same vicinity.

Question 12

The reason coral reefs are among the most productive and successful ecosystems is due to

A)the coral-dinoflagellate mutualistic relationship.
B)the lichen mutualistic relationship.
C)commensalisms.
D)all of these

Question 13

In the rumen,food is quickly attacked by cellulase

A)enzymes produced by the ruminant.
B)enzymes produced by microbes.
C)enzymes produced by both the ruminant and the microbe.
D)archeons.

Question 14

Any microorganism that spends a portion of its life associated with another organism of a different species is engaged in

A)symbiosis.
B)synergy.
C)parasitism.
D)commensalism.

Question 15

Which of the following is not part of the lichen association?

A)ascomycetes
B)green algae
C)brown algae
D)cyanobacteria

Question 16

An example of microbial ___________ is the ability of Vampirococcus to attach to the outer membrane of its prey and then secrete degradative enzymes that result in the release of the prey's cytoplasmic contents.

Question 17

A close physical relationship between two different species that may or may not be beneficial is called __________.

Question 18

Which of the following is not a category of symbiosis?

A)mutualism
B)phoresis
C)commensalism
D)parasitism

Question 19

The specialized structure in a tube worm in which endosymbiotic,chemolithotrophic bacteria live is called a(n)__________.

Question 20

In mutualism

A)the mutualist is dependent on the host.
B)a reciprocal benefit accrues to both partners.
C)the partners will not survive separately in many cases.
D)all of these

Question 21

A unidirectional process where a specific compound released by one organism has a negative effect on another organism is called

A)predation.
B)commensalism.
C)negative cooperation.
D)amensalism.

Question 22

The average adult carries 10 times more microbial cells (10¹⁴)than human cells (average about 10¹³).

Question 23

In the rumen,the carbohydrate fermentation end products include

A)acetate.
B)carbon dioxide.
C)methane.
D)all of these

Question 24

A _________ is any disease-producing microorganism.

Question 25

____________ arises when different microbes within a population or community try to acquire the same resource.

A)Amensalism
B)Competition
C)Disruption
D)Syntropism

Question 26

________________ is a predator that bores a hole through the outer membrane of its gram-negative bacterial prey and then reproduces in the periplasm.

A)Vampirococcus
B)Bdellovibrio
C)Daptobacter
D)Syntrophobacter

Question 27

When Nitrobacter utilizes nitrite produced from ammonia by Nitrosomonas to obtain energy by converting the nitrite to nitrate,the relationship between the two organisms is

A)commensal.
B)amensal.
C)mutual.
D)parasitic.

Question 28

Pseudonocardia is an organism that is hosted by

A)wood-eating insects.
B)marine invertebrates.
C)ants that cultivate fungal gardens.
D)people with severe acne.

Question 29

Mussels and sponges sometimes contain methanotrophs as intracellular symbionts because the methanotrophs

A)remove otherwise toxic levels of methane from the environment.
B)convert methane to carbohydrate for use by the host.
C)allow the partnership to use hydrogen sulfide as a source of electrons.
D)all of the choices

Question 30

Methanogens are always engaged in relationships with other microbes because methane production requires

A)removal of oxygen from the environment by another microbe.
B)energy provided by another microbe.
C)interspecies hydrogen transfer.
D)none of the choices

Question 31

In lichens,the fungi send projections of their hyphae across the algal cell wall in order to obtain nutrients from the photosynthetic partner.These projections are called

A)mycelia.
B)hyphal extensions.
C)haustoria.
D)lichenthropes.

Question 32

Dinoflagellates that exist endosymbiotically within a variety of marine invertebrates are called

A)endoflagellates.
B)parasites.
C)endotrophic.
D)zooxanthellae.

Question 33

Microbes such as Lactobacillus acidophilus colonize the human vagina by fermenting

A)glycogen.
B)glucose.
C)lactose.
D)sucrose.

Question 34

The ectosymbionts of ruminant animals are useful to their hosts in which of the following ways?

A)They digest the cellulose of plant cell walls.
B)They produce most of the vitamins needed by the ruminant.
C)They convert glucose to organic acids.
D)all of the choices

Question 35

A physical relationship where an organism hosts more than one symbiont is known as a

A)clade.
B)consortium.
C)partnership.
D)cojoining.

Question 36

The filamentous bacteria that grow on the dorsal surface of certain polychaete worms

A)fend off potential predators with toxins.
B)carry out photosythesis.
C)may provide the worm with protection from toxic metals.
D)all of the choices

Question 37

Buchnera aphidicola provides ___________ to its aphid host that are essential to the survival of the insect.

A)carbohydrates
B)vitamins
C)amino acids
D)cellulases

Question 38

The rickettsial parasite Wolbachia pipientis can

A)sometimes alter the sex of an infected wasp.
B)confer toxicity to the sting of an infected wasp.
C)enhance the life-span of an infected wasp.
D)none of the choices

Question 39

Riftia tube worms make a unique kind of hemoglobin to

A)transport oxygen.
B)transport hydrogen sulfide.
C)to assist in the transport of carbon dioxide.
D)all of the choices

Question 40

Microorganisms commonly associated with the human body are traditionally referred to as the

A)normal microbial flora.
B)normal microbes.
C)normal microbiota.
D)normal microbial flora or the normal microbiota.

Question 41

Microbiota of the skin are most likely to be found

A)where there is little moisture.
B)where the pH of the skin secretions is below 4.
C)in association with oil and sweat glands.
D)all of the choices

Question 42

When members of the normal microbiota of the human body become pathogenic and produce disease under certain circumstances,they are referred to as ______________ pathogens.

A)partial
B)conditional
C)occasional
D)opportunistic

Question 43

The lungs are protected from microorganisms by

A)the ciliated epithelial cells.
B)lysozyme in mucus.
C)phagocytic action of alveolar macrophages.
D)all of these

Question 44

The lower genitourinary tract is usually free of microorganisms.

Question 45

A species of bacterium associated with the oil glands of the skin belongs to the genus

A)Staphylococcus.
B)Pityrosporum.
C)Propionibacterium.
D)Pityrosporum.

Question 46

Which of the following areas of the human body is(are)not normally free of microorganisms?

A)respiratory tract
B)intestinal tract
C)eyes
D)all of the choices

Question 47

Gram-positive bacteria such as Propionibacterium acnes limit the growth of gram-negative bacteria and some fungi on the human skin by converting secreted __________ to compounds with antimicrobial activity.

A)lipids
B)organic acids
C)salts
D)urea

Question 48

The lower respiratory tract has a normal microbiota.

Question 49

The oral cavity of humans normally becomes colonized with microorganisms within hours after birth.

Question 50

Human sweat has antimicrobial activity due to

A)production of an antimicrobial peptide called cathelicidins.
B)competition with normal sweat gland flora.
C)production of low molecular weight compounds that maintain an alkaline pH.
D)production of low molecular weight compounds that chelate free iron.

Question 51

Many anaerobic gram-negative bacteria are normally found in the duodenum.

Question 52

The term that refers to those microbes found as symbionts in a short relationship of a nongrowing nature is __________.

Question 53

The skin surface (epidermis)is a very favorable environment for colonization by microorganisms.

Question 54

A bacterial genus that is found in large numbers in the intestinal tract of breast-fed infants is

A)Bacteroides.
B)Bifidobacteria.
C)Escherichia.
D)Doderlein's bacillus.

Question 55

Which of the following would you not find in the nasopharynx?

A)Streptococcus pneumoniae
B)Neisseria meningitidis
C)Haemophilus influenzae
D)Branhamella catarrhalis

Question 56

Which of the following would you expect to find in the tonsilar crypts?

A)Micrococcus
B)Staphylococcus
C)Streptococcus
D)Neisseria

Question 57

Escherichia coli is the most prevalent bacterium found in the colon.

Question 58

Under normal circumstances,the microbiota of the skin is kept in check by

A)a high pH (above 8).
B)a slightly acidic pH.
C)phagocytic activity.
D)excessive moisture.