Question 1

A long,tight,spiral-shaped bacteria is found in the gut of termites.This bacteria is most likely a(n)

Accepted Answer

The characteristic long, tight, spiral shape describes a spirochete, which is a type of bacteria found in the gut of many termites as a symbiont. Enterobacteria and cyanobacteria are not typically found in termite guts, and chlamydia are intracellular parasites but do not have the spiral shape described.

Question 2

During infertility testing,a young woman is found to have pelvic inflammatory disease,or PID,from persistent inflammation of her fallopian tubes.Although she has never been treated for any sexually transmitted disease,her physician suspects she has an untreated bacterial infection,which is relatively common in the United States.Which bacteria is most likely causing her infection?

Accepted Answer

Chlamydia trachomatis is a common sexually transmitted bacterium that can cause PID, which results in inflammation of the fallopian tubes. Borrelia burgdorferi and Borrelia recurrentis are both bacteria that cause Lyme disease and relapsing fever, respectively, but they are not associated with PID. Haemophilus influenza is a bacterium that can cause respiratory infections but is not associated with PID.

Question 3

Which of the following statements correctly describes a lichen?

Accepted Answer

Lichens are a mutualistic relationship between a fungus and either a cyanobacteria or an algae, in which the photosynthetic partner provides carbon compounds and the fungal partner provides structural support and protection. In the case of a cyanobacteria partner, it also provides nitrogen to the fungus.

Question 4

What is the relationship between plants and cyanobacteria?

Accepted Answer

Cyanobacteria were internalized by plant cells and became chloroplasts through endosymbiosis. This is the origin of chloroplasts in plants.

Question 5

Which of the following is considered metabolically INACTIVE?

Accepted Answer

Elementary bodies of Chlamydia trachomatis are considered metabolically inactive because they are in a dormant state and do not carry out cellular functions such as protein synthesis or metabolism.

Question 6

A tissue sample from a woman's reproductive tract reveals human cells that contain growing and dividing reticulate bodies with netlike chromosomes.Which of the following bacterial species has most likely infected the human cells?

Accepted Answer

The presence of reticulate bodies with netlike chromosomes indicates an infection with Chlamydia trachomatis, which is known to cause sexually transmitted infections and can infect cells of the reproductive tract. Treponema pallidum causes syphilis, but does not form reticulate bodies in human cells. Helicobacter pylori is a bacterium that infects the stomach and does not typically invade human cells. Coxiella burnetii is the causative agent of Q fever and does not invade human cells in the same way as Chlamydia trachomatis.

Question 7

What internal structure is indicated by arrows on this figure?

Accepted Answer

The arrows on the figure indicate the presence of flagella, which are long whip-like structures that some cells use for movement. The other options (cilia, mitochondria, and nucleus) are not indicated by the arrows.

Question 8

Spirochete cells are unique because they possess

Accepted Answer

Spirochete cells have periplasmic flagella, also known as axial filaments, which are located between the outer membrane and the peptidoglycan layer. These flagella allow the spirochetes to move in a corkscrew-like motion. The other options are not characteristics of spirochete cells.

Question 9

A black Labrador puppy goes swimming in a nutrient-rich pond one summer afternoon.Within hours the puppy begins vomiting and showing signs of damage to his nervous system.The puppy's owner takes him to a local veterinarian and is told the puppy also has liver damage.Upon questioning,the owner recalls the pond water the puppy went swimming in was green and cloudy.The veterinarian suspects the puppy was exposed to

Accepted Answer

The green and cloudy appearance of the pond water suggests a bloom of cyanobacteria, which can produce toxins called microcystins that can lead to liver damage and neurological symptoms in animals that ingest them.

Question 10

Which of the following causative agents and diseases are correctly paired?

Accepted Answer

Borrelia burgdorferi is the causative agent of Lyme disease. Treponema pallidum causes syphilis and yaws, while Treponema pallidum pertenue causes yaws specifically. Borrelia recurrentis causes relapsing fever.

Question 11

The most abundant phototrophs in the ocean are single-celled and include the genera

Accepted Answer

Synechococcus and Prochlorococcus are the most abundant phototrophs in the ocean and are both single-celled organisms. Treponema and Chlamydia are bacterial pathogens that are not phototrophic, while Merismopedia and Nostoc are both cyanobacteria, but they are not as abundant as Synechococcus and Prochlorococcus in the ocean. Oscillatoria is another type of cyanobacteria, but it is also not as abundant as Synechococcus and Prochlorococcus in the ocean.

Question 12

Cyanobacteria and the bacterial genus Rhizobium are both known to contribute to the environment by

Accepted Answer

Cyanobacteria and Rhizobium are both known for their ability to fix nitrogen. Cyanobacteria are photosynthetic bacteria that can convert atmospheric nitrogen into a form that plants can use, while Rhizobium are soil bacteria that form symbiotic relationships with legumes, helping them to fix atmospheric nitrogen into the soil.

Question 13

A blue-green bloom of cyanobacteria leads to an ocean beach closure.What is the primary concern?

Accepted Answer

Cyanobacteria can produce harmful toxins that can damage the liver, leading to illness or even death in humans who come in contact with the water. This is the primary concern with a blue-green bloom of cyanobacteria, and why an ocean beach closure is necessary to protect public health.

Question 14

This figure shows two distinctive life stages associated with a bacteria that

Accepted Answer

The answer of This figure shows two distinctive life stages...

Question 15

Which of the following statements accurately describes the transmission of one Chlamydia species in human populations?

Accepted Answer

Chlamydia species are bacteria that have a unique life cycle, with two distinct forms: elementary bodies (EBs) and reticulate bodies (RBs). The RBs infect host cells and replicate, eventually turning into EBs, which are then released when the infected cell lyses. This cycle is what allows Chlamydia to spread from person to person, primarily through sexual contact. Choice A is incorrect as it only partially describes the attachment process, while ignoring the release of EBs. Choice B is incorrect as it implies that Chlamydia is an environmental pathogen, which is not the case. Choice C is incorrect as it describes a hypothetical scenario involving fleas, which is not known to occur in human populations.

Question 16

Trachoma,an ancient eye disease,is caused by

Accepted Answer

Trachoma is caused by Chlamydia trachomatis, a bacterium that is spread through direct or indirect contact with the eye, nose, or throat secretions of infected individuals.

Question 17

How is the specialized shape of a spirochete advantageous?

Accepted Answer

The specialized shape of a spirochete, with its spiral form, allows it to rotate and move through viscous environments like tissues and mucus more efficiently than other shapes, which are more limited in their movement.

Question 18

CASE HISTORY
Michael,45 years old,is a cook at a fast-food restaurant in Rome,Georgia.He went to see his physician because he was feeling fatigued,was unable to sleep,had lost his appetite,and had been coughing for several weeks.His sputum (material coughed from deep in the lung)contained acid-fast bacilli,and a chest X-ray revealed scattered,small (1-5 mm)granulomas (nodules of inflammation)throughout both lobes of the lung.The physician diagnosed Michael with secondary tuberculosis.Secondary tuberculosis is caused by bacteria reactivated from old lesions in which bacteria have persisted in a dormant state.The causative bacterium is Mycobacterium tuberculosis,a facultative intracellular pathogen that infects only humans and is transmitted through respiratory droplets.Michael was placed in isolation and started on a long-term,four-drug treatment regimen consisting of isoniazid (fatty acid synthesis inhibitor),rifampin (transcription inhibitor),pyrazinamide (fatty acid synthesis inhibitor),and streptomycin (protein synthesis inhibitor).The four-drug therapy continued for two months,followed by four months with isoniazid and rifampin only.Michael responded well to treatment.Luckily,he was not infected with one of the highly dangerous multidrug-resistant strains (MDr-tB).
Mycobacterium tuberculosis is a member of the Actinobacterium,which causes disease in humans,though other members of this group are environmental microorganisms and some produce useful antibiotics.Which other Actinobacterium is a pathogen of humans?

Accepted Answer

Corynebacterium diphtheria is a pathogen of humans that causes the disease diphtheria, which primarily affects the respiratory tract.

Question 19

A 23-year-old man visited a community clinic after receiving notification from the health department that a previous sexual partner was diagnosed with a sexually transmitted disease.Although he does not recall having any ulcers,he currently has a macular rash on his trunk,arms,hands,and feet.He is tested for evidence of

Accepted Answer

The macular rash on the trunk, arms, hands, and feet is suggestive of secondary syphilis, which is caused by Treponema pallidum pallidum. Testing for evidence of this bacterium would be appropriate in this case. The other options are unlikely to cause the symptoms described.

Question 20

The structure highlighted with an arrow in step 6 of this figure is best described as a

Accepted Answer

The answer of The structure highlighted with an arrow in...

Quiz 10: Bacterial Diversity