Question 1

What internal structure is indicated by arrows on this figure?

Accepted Answer

The arrows are pointing to structures that resemble flagella, which are long, whip-like structures that aid in cell movement.

Question 2

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...

Question 3

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 4

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

Accepted Answer

Spirochetes are spiral-shaped bacteria commonly found in the gut of termites as beneficial symbionts. They play an important role in breaking down cellulose in wood, which termites feed on. Enterobacteria and chlamydia are not commonly found in termite guts, and cyanobacteria are not spiral-shaped.

Question 5

Trachoma,an ancient eye disease,is caused by

Accepted Answer

Trachoma is caused by the bacterium Chlamydia trachomatis.

Question 6

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 as they are well adapted to low nutrient environments and can thrive in various oceanic regions.

Question 7

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 an Actinobacterium that is a pathogen of humans and causes diphtheria, a respiratory disease characterized by a pseudomembrane in the throat that can cause airway obstruction and death. Propionibacterium freudenreichii is a non-pathogenic Actinobacterium commonly found on human skin and used in the production of Swiss cheese. Streptomyces coelicolor is an Actinobacterium commonly used in the production of antibiotics and other secondary metabolites. Actinomyces israelii is an Actinobacterium that can cause a variety of infections in humans, including actinomycosis, a chronic infection characterized by the formation of abscesses and draining sinuses.

Question 8

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

Accepted Answer

Cyanobacteria have the ability to produce toxins, including liver-damaging ones, which can pose a danger to humans who come in contact with the water.

Answer: D
 Cyanobacteria can lead to a decrease in oxygen in the water, making it difficult for fish to breathe and causing them to accumulate toxins. This can also impact other aquatic organisms in the ecosystem.

Question 9

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

Chlamydia trachomatis is an intracellular bacterium that can infect the reproductive tract of women and can appear as reticulate bodies with netlike chromosomes during its life cycle. Treponema pallidum (A) causes syphilis and does not exhibit this characteristic feature. Helicobacter pylori (B) is a bacteria that colonizes the stomach and intestines and does not infect the reproductive tract. Coxiella burnetii (D) is the cause of Q fever, an infection that does not typically involve the reproductive tract.

Question 10

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

Accepted Answer

Cyanobacteria and Rhizobium are both nitrogen-fixing bacteria. They have the unique ability to convert atmospheric nitrogen into a more usable form for plants and other organisms, which helps to enrich the soil and promote plant growth. While cyanobacteria also produce oxygen, this is not their primary contribution to the environment. Decomposing dead matter and producing antibiotics are not mentioned as typical roles of these bacteria.

Question 11

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 bacterial infection in the United States that can lead to PID if left untreated. It is often asymptomatic, which is why the young woman may not have realized she had an infection. The other options are not typically associated with causing PID.

Question 12

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 an overgrowth of cyanobacteria, also known as blue-green algae. Some cyanobacteria produce toxins that can cause liver damage and damage to the nervous system, which may explain the puppy's symptoms.

Question 13

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

Accepted Answer

The transmission of Chlamydia species in human populations involves the replication of reticulate bodies inside host cells which then develop into elementary bodies. These elementary bodies are released when the host cells lyse, leading to the spread of infection to nearby cells or to sexual partners. This mode of transmission is specific to Chlamydia species that infect humans.

Question 14

How is the specialized shape of a spirochete advantageous?

Accepted Answer

The specialized shape of a spirochete, which is a long, thin, spiral shape, allows it to move through viscous environments in a corkscrew motion. This enables spirochetes to move through the mucus layer in the body, as well as penetrate host tissues and evade the immune system. The corkscrew motion is also advantageous for spirochetes to move through the soil, which is their natural habitat.

Question 15

Which of the following is considered metabolically INACTIVE?

Accepted Answer

Elementary bodies of Chlamydia trachomatis are metabolically inactive and are the infectious form of the bacterium. They are able to survive in the environment and infect host cells. Once inside the host cell, they differentiate into reticulate bodies and become metabolically active.

Question 16

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

Accepted Answer

Borrelia burgdorferi is causative agent for Lyme disease.

Answer: B
 Treponema pallidum is causative agent for syphilis, not yaws.

Answer: A
 Treponema pallidum pertenue is the causative agent for yaws, not relapsing fever.

Answer: A
 Borrelia recurrentis is the causative agent for relapsing fever, not syphilis.

Question 17

What is the relationship between plants and cyanobacteria?

Accepted Answer

Cyanobacteria were internalized by plant cells and not broken down, which led to the formation of chloroplasts. This is believed to be the origin of chloroplasts in photosynthetic eukaryotic organisms such as plants.

Question 18

Spirochete cells are unique because they possess

Accepted Answer

Spirochete cells are unique because they possess periplasmic flagella, which are located within the periplasmic space between the outer and inner cell membranes. These flagella allow spirochetes to move in a corkscrew-like motion, which is different from the movement of other bacteria that use external flagella. Additionally, spirochetes do not possess multiple nuclei, a thick outer sheath of lipopolysaccharides, or two distinctive life stages.

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 patient's trunk, arms, hands, and feet is a characteristic symptom of secondary syphilis caused by Treponema pallidum pallidum. The other options (B, C, and D) do not typically cause this type of rash.

Question 20

Which of the following statements correctly describes a lichen?

Accepted Answer

A lichen is a mutualistic relationship between a fungus and either cyanobacteria or green algae. In this relationship, the cyanobacteria or green algae provide photosynthetically-fixed carbon and nitrogen to the fungus, which provides a protective and supportive environment for the photosynthetic partner.

Quiz 10: Bacterial Diversity