Microbiology Exam 1 Practice Test and Clicker Questions

Which of the following is NOT a eukaryote?
A. Algae
B. Protists
C. Archaea
D. Protozoa

Consider the case of Lyme disease, caused by the bacterium Borrelia burgdorferi, and Koch’s postulates. What would have to occur in order to satisfy Koch’s second postulate?
A. Borrelia burgdorferi would have to be found present in a host with Lyme disease but absent from a healthy host.
B. Borrelia burgdorferi isolated from diseased host would have to be inoculated into a healthy host, resulting in Lyme disease.
C. The genome of Borrelia burgdorferi would have to be sequenced to show the Lyme disease-causing genes.
D. Borrelia burgdorferi would have to be isolated from a host suffering from Lyme disease and grown in pure culture.

How do bacteria, such as Escherichia coli, stay attached to body cells, tissues, or other surfaces?
A. Invasiveness
B. Virulence
C. Apoptosis
D. Adhesins

Two students are working together to Gram stain a mix of Gram positive and Gram negative cells. One of the students accidentally uses a bottle of water instead of ethanol during the decolorization step. How would this mistake alter their results?
A. Both Gram positive and Gram negative cells would appear pink.
B. Gram positive cells would appear purple and Gram negative cells would appear pink.
C. Gram positive cells would appear pink and Gram negative cells would appear purple.
D. Both Gram positive and Gram negative cells would appear purple.

Who was the first individual to observe cells?
A. Robert Koch
B. Antonie van Leeuwenhoek
C. Robert Hooke
D. Louis Pasteur

In addition to her work as a famous nurse, how else did Florence Nightingale contribute to the field of microbiology?
A. She developed techniques to isolate a pure culture of microorganisms.
B. She founded the science of medical statistics.
C. She used the scientific method to establish the microbial cause of disease.
D. She discovered the use of vaccinations to prevent disease.

Lipopolysaccharides are part of _____________.
A. the outer membrane
B. the cell membrane
C. the cell wall
D. the inner membrane

Prions are composed of ___________.
A. aberrant proteins
B. nucleic acids
C. sugars
D. normal proteins

Which of the following was NOT used to develop the germ theory of disease?
A. microbial culture
B. spontaneous generation
C. statistical analysis
D. microscopy

In many cases of disease, the causative agent can be linked to one bacterial pathogen. However, when you are collecting a specimen from a patient, it is difficult to obtain just one species of bacterium. Because of this difficulty, good methods for bacterial isolation are needed to obtain a pure culture (a single, genetically homogeneous strain of a single species). Why is a pure culture necessary for the diagnostic process?
A. mixed culture will not grow under lab conditions.
B. a pure culture is required for vaccine production.
C. biochemical tests may be confounded when working with a mixed culture.
D. a pure culture is useful in inoculating other patients.

You want to use a microscope to look at the microbe Giardia lamblia. Specifically, you would like to see critical detail of internal structures. Which type of microscope would be best to use?
A. a phase-contrast microscope
B. a light microscope
C. a scanning electron microscope
D. a transmission electron microscope

Which of the following is a potential problem with satisfying Koch’s third postulate in practice?
A. Some disease-causing microorganisms may be found in healthy individuals.
B. Some disease-causing microorganisms only cause infection in humans, so no animal models are available.
C. Not all disease-causing microorganisms can be isolated and grown in pure culture in the laboratory.
D. Some disease-causing microorganisms will not cause disease in all individuals.

The bacterial cell wall is composed of ________.
A. cellulose
B. chitin
C. peptidoglycan
D. phospholipids

Which of the following would be a symptom?
A. white blood cell count
B. runny nose
C. headache
D. rash

The curve in Pasteur’s swan necked flask was important because ____.
A. it prevented flies from escaping the flask.
B. t allowed only warm air to reach the infusion.
C. It trapped microbes that otherwise would have entered the flask.
D. It prevented oxygen from reaching organisms inside the flask.

The Gram stain is useful for distinguishing among which types of microbes?
A. algae
B. bacteria
C. fungi
D. protozoa
E. all of the above

Select the most correct statement about the Gram stain:
A. Iodine acts as the decolorizer in the Gram stain.
B. Gram-positive cells retain the crystal violet dye and the gram-negative cells lose the dye following the decolorizer step.
C. To obtain the best Gram stain reaction, your cultures should be at least 48 hours old.
D. All of the above are correct.

The peptidoglycan layer of the cell wall:
A. consists of lipopolysaccharides
B. represents a lipid bilayer
C. lacks teichoic acids
D. is only present in gram-positive organisms.
E. none of the above are true

The counterstain in the gram reaction is:
A. Carbolfuchsin
B. Malachite green
C. Safranin
D. Crystal violet

The first use of aseptic technique to attempt to control the spread of infection can be traced to:
A. Lister
B. Jenner
C. Koch
D. Fleming

Nosocomial infections are:
A. acquired by mosquito, flea, tick
B. Must be reported to the public
C. Are acquired in the hospital
D. Are often most acquired in day cares

A bacterial population grows most rapidly during ________ phase.
A. stationary
B. Lag
C. Death
D. Log/exponential

Penicillin was discovered by ______, and was isolated by _______.
A. Pasteur; Fleming
B. Chain and Florey; Koch
C. Fleming; Chain and Florey
D. Pasteur; Koch

Endospores are:
A. Metabolically active
B. Protective structures
C. Reproductive structures
D. Found only in Gram- organisms

_______ Bacteriophage infection results in immediate death of a host cell.
A. Lysogenic
B. Lytic
C. Latent
D. Chronic

Pili enable bacterial __________.
A. Adherence
B. Chemotaxis
C. Symport
D. Locomotion

Bacterial capsules can best be visualized by ______ staining.
A. Flagellar
B. Crystal Violet
C. Gram
D. Negative

Most human pathogens are:
A. Psychrophiles
B. Mesophiles
C. Thermophiles
D. Acidophiles

Lipopolysaccharides are found in:
A. Gram-Positive Bacteria
B. Gram-Negative Bacteria
C. Eukaryotic Microbes
D. All of the above

Which microscope technique is best used to visualize the surface of cells and viruses?
A. Light Microscopy
B. Transmission Electron Microscopy
C. Scanning Electron Microscopy
D. Negative Microscopy

An island nation normally has a low background level of cholera. After an earthquake, sanitation is disrupted and cholera cases spike to high levels on the island, but not in other areas of the world. This spike in cholera is an example of a(n):
A. endemic disease
B. epidemic disease
C. pandemic disease
D. opportunistic infection

Which of the following is a symptom?
A. A rash
B. Swollen glands
C. Jaundice (yellow tinge to the skin)
D. Muscle aches

A rash caused by Rocky Mountain spotted fever is an example of:
A. Sign
B. Symptom
C. Sequelae
D. Fomite

A mosquito can transmit a viral pathogen into humans. The mosquito is an example of a(n):
A. Fomite
B. Symptom
C. Vector
D. Endoparasite

Which of the following is NOT a microbe?
A. E. Coli, a bacterium living in the intestinal tract.
B. Methanococcus jannaschi, an archaean living in a marsh.
C. human immunodeficiency virus (HIV) infecting a patient’s white blood cells
D. Pelomyxa species, a large amoeba, living in a freshwater pond.
E. Taenia solium, a parasitic tapeworm found in swine.

Antonie van Leeuwenhoek made which contribution to the microbial world?
A. he was the first individual to observe single-celled microbes
B. He was the first microscopist to publish a study of the world as seen under a microscope
C. He sought to disprove the spontaneous generation of microbes
D. He discovered that fermentation was caused by yeast, a single-celled fungus
E. He was the first to attempt to quantify the role of disease in population mortality.

Which scientist was the first to develop a set of criteria to establish a causative link between an infectious agent and a disease?
A. Pasteur
B. Spallanzani
C. Nightingale
D. Koch
E. Hooke

The first Eukaryotic cells are thought to have originated by which of the following processes?
A. Symbiosis
B. Endosymbiosis
C. Pinocytosis
D. Exocytosis
E. Exosymbiosis

Which of the following modes of transmission is DIRECT?
A. a baby’s teething ring
B. a flea
C. creek water
D. a sneeze
E. lettuce leaves in a salad

Which of the following scenarios describes an opportunistic pathogen?
A. diarrhea as a result of eating chicken contaminated with Salmonella
B. Bacterial pneumonia following a case of the flu
C. a case of Strep throat
D. an STD caused by unprotected sexual intercourse
E. Conjunctivitis (Pink Eye) caused by Staphylococcus aureus

Which of the following scenarios is NOT a host-pathogen interaction?
A. a virus binding to its receptor on a host cell
B. a change in surface proteins by the pathogen
C. a signal from the pathogen that causes the hosts immune cells to initiate apoptosis (programmed cell death)
D. iron-binding proteins used by the host to sequester available iron
E. a gene for antibiotic resistance in the pathogen

Septicemia is defined as the following:
A. the presence of bacteria in the blood
B. the presence of viruses in the blood
C. the presence and replication of viruses in the blood
D. the presence and replication of bacteria in the blood
E. the presence of toxins in the blood

Which of the following would be the best method to observe the surface of Plasmodium falciparum, the parasite that causes Malaria?
A. light microscopy
B. dark-field microscopy
C. transmission electron microscopy
D. scanning electron microscopy
E. fluorescence microscopy

Which of the following structures/molecules would be a good antibiotic target?
A. cell wall
C. sex pilus
D. ATP synthase
E. there is not enough information to answer this question.

You have discovered a new species of microbe. You want to determine if it is prokaryotic or eukaryotic. The presence of which of the following organelles will help you determine this?
A. plasma membrane
B. Mitochondria
C. Ribosome
D. Cytoplasm
E. there is not enough info to answer this question.

A 70 year old man is admitted to the ER with massive bloody diarrhea due to an infection with enterohemorrhagic E. coli. He is treated with IV fluids and given an antibiotic. The following day, he suddenly becomes worse, spiking a fever and showing symptoms of shock. Which of the following is most likely the reason his symptoms became worse after the treatment?
A. the E. coli is resistant to the antibiotic given.
B. the antibiotic killed all of his “good” bacteria that help fight infections.
C. he developed a secondary infection while in the hospital
D. The wrong antibiotic was used to treat the infection and endotoxin was released from the lysed cells, causing worsening of his illness
E. there is not enough info to answer this question