Micro 1 Exam 1

Some bacteria grow at 25° C or 42° C, but diagnostic laboratories routinely grow pathogenic bacteria at what temperature? a. 35° C b. 60° C c. 30° C d. 10° C

a. 35° C

In what staining procedure does carbolfuchsin penetrate the bacterial cell wall through heat or detergent treatment? a. Acid-fast stain b. Gram stain c. Acridine orange stain d. Endospore stain

a. Acid-fast stain

The following describes the log phase of bacterial growth: a. Bacteria doubling with each generation time b. Number of nonviable bacterial cells exceeds the number of viable cells c. Preparing to divide d. Limited nutrients with bacteria count remaining constant

a. Bacteria doubling with each generation time

Which is a biochemical process carried out by both obligate and facultative anaerobes? a. Fermentation b. Respiration c. Reduction d. Oxidation

a. Fermentation

The outer cell wall of the gram-negative bacteria serves three important functions, which includes all the following, except: a. It provides an attachment site for the flagella, which will act in locomotion. b. It provides attachment sites that enhance adhesion to host cells. c. It acts as a barrier to hydrophobic compounds and harmful substances. d. It acts as a sieve.

a. It provides an attachment site for the flagella, which will act in locomotion.

This form of DNA is commonly found in eukaryotic cells. a. Linear b. Plasmid c. Colloid d. Circular

a. Linear

Diagnostic microbiologists apply placement and naming of bacterial organisms into all the following categories, except a. Order b. Species c. Genus d. Family

a. Order

What structure is described as a phospholipid bilayer embedded with proteins and sterols that regulates the type and amount of chemicals that pass in and out of a cell? a. Plasma membrane b. Endoplasmic reticulum c. Mitochondria d. Cell wall

a. Plasma membrane

The three basic shapes of bacteria include all the following, except a. cell wall deficient. b. cocci. c. bacilli. d. spirochetes.

a. cell wall deficient.

A microbiology technologist performs a traditional bacterial stain on a colony from a wound culture that is suspected to contain bacteria from the genus Clostridium. The unstained areas in the bacterial cell observed by the technologist are called a. endospores. b. mitochondria. c. ribosomes. d. cilia.

a. endospores.

Diagnostic schemes in the microbiology laboratory typically analyze each unknown bacterium's metabolic processes for all the following, except a. energy utilization for metabolic processes. b. production of an acid or alkaline pH in the test medium. c. utilization of a variety of substrates as carbon sources. d. production of specific end products from specific substrates.

a. energy utilization for metabolic processes.

Healthy people are colonized by many different bacteria in many different sites. These bacteria are referred to as a. indigenous flora. b. maintenance flora. c. transient flora. d. carrier flora.

a. indigenous flora.

The human body is constantly challenged by pathogens in the environment. It is not infected by every pathogen it encounters because the microbial flora a. produce conditions at the microenvironmental level that block colonization. b. activate and support the action of antigen-presenting cells, cytokines, and cell-mediated immunity. c. prime our immune system. d. engulf the pathogenic bacteria.

a. produce conditions at the microenvironmental level that block colonization.

In the laboratory, the clinical microbiologist is responsible for all the following, except a. selecting treatment for patients. b. isolating microorganisms. c. analyzing bacteria that cause disease. d. identifying microorganisms.

a. selecting treatment for patients.

Mycoplasma and Ureaplasma spp. must have media supplemented with serum or sugar as nutrients and because a. they lack cell walls. b. the sterols in their cell walls are soluble in normal bacterial media. c. their cell walls contain detoxifying enzymes. d. their cell walls contain only peptidoglycan.

a. they lack cell walls.

What is the purpose of a capsule? a. Prevent osmotic rupture of the cell membrane b. Act as a virulence factor in helping the pathogen evade phagocytosis c. Make up the periplasmic space d. Provide an attachment site for somatic antigens

b. Act as a virulence factor in helping the pathogen evade phagocytosis

The laboratory receives a specimen in which the doctor suspects that the infecting organism is Haemophilus influenzae. This organism grows best in an atmosphere that contains 5% to 10% carbon dioxide. It is therefore classified as what type of bacteria? a. Facultative anaerobe b. Capnophilic c. Obligate aerobe

b. Capnophilic

Mycobacteria have a gram-positive cell wall structure with a waxy layer containing these two compounds. a. Mycolic acid and lipopolysaccharides b. Glycolipids and mycolic acid c. Glycolipids and phospholipids d. Lipopolysaccharides and phospholipids

b. Glycolipids and mycolic acid

Prokaryotic cells have which of the following structures in their cytoplasm? a. Golgi apparatus b. Ribosomes c. Mitochondria d. Endoplasmic reticulum

b. Ribosomes

What makes the interior of the plasma membrane potentially impermeable to water-soluble molecules? a. The ion channels are found there. b. The hydrophobic tails of the phospholipid molecules are found there. c. The hydrophilic tails of the phospholipid molecules are found there. d. The cholesterol molecules in the plasma membrane are found solely in the interior of the membrane.

b. The hydrophobic tails of the phospholipid molecules are found there.

A microbiologist is working with two separate cultures of the same organism. The bacteria in one culture are resistant to penicillin, whereas the bacteria in the other culture are susceptible to penicillin. The bacteria from both cultures are mixed together, and all the resulting bacteria are resistant to penicillin. What caused this phenomenon? a. The plasmid carrying the susceptibility gene was transferred to the resistant population of bacteria. b. The plasmid carrying the resistance gene was transferred to the susceptible population of bacteria. c. An IS element was inserted into the genome of the susceptible bacterial population. d. A frame-shift mutation occurred that allowed the susceptible population of bacteria to develop resistance to penicillin.

b. The plasmid carrying the resistance gene was transferred to the susceptible population of bacteria.

What enables the microbiologist to select the correct media for primary culture and optimize the chance of isolating a pathogenic organism? a. Understanding the cell structure and biochemical pathways of an organism b. Understanding the growth requirements of potential pathogens at specific body site c. Knowing the differences in cell walls of particular bacteria d. Determining staining characteristics

b. Understanding the growth requirements of potential pathogens at specific body site

If bacteria utilize various carbohydrates for growth, they are usually detected by a. alkaline production and change of color from the pH indicator. b. acid production and change of color from the pH indicator. c. production of carbon dioxide. d. Production of keto acids.

b. acid production and change of color from the pH indicator.

The Gram stain is a routine stain used in bacteriology to determine gram-positive and gram-negative bacteria based on the a. composition of the bacterial cell membrane. b. composition of the bacterial cell wall. c. composition of the bacterial pili. d. phenotypic characteristics of the organism.

b. composition of the bacterial cell wall.

Genes that code for antibiotic resistance are often found on small, circular pieces of DNA. These DNA pieces are called a. genomes. b. plasmids. c. phenotypes. d. chromosomes.

b. plasmids.

Organisms that participate in a biological relationship where both benefit from one another are called a. hosts b. symbionts c. parasites

b. symbionts

What class of organisms, such as the Streptococcus sp., can survive in the presence of oxygen but do not use oxygen in its metabolic processes? a. Microaerophilic b. Facultative anaerobe c. Aerotolerant anaerobe d. Obligate anaerobe

c. Aerotolerant anaerobe

Which of the following environmental factors influence the growth of bacteria in the laboratory? a. Gaseous composition of the atmosphere b. Temperature c. All of the above d. pH

c. All of the above

Who was considered the father of protozoology and bacteriology? a. Louis Pasteur b. Carl Landsteiner c. Anton van Leeuwenhoek d. Michael Douglas

c. Anton van Leeuwenhoek

A _____ is a single, closed, circular piece of DNA that is supercoiled to fit inside a bacterial cell. a. Phenotype b. transposon c. Chromosome d. frame-shift mutation

c. Chromosome

A clinical laboratory scientist is working on the bench, reading plates, and notices that a culture has both a unicellular form and a filamentous form. What type of organism exhibits these forms? a. Virus b. Bacteria c. Fungi d. Parasite

c. Fungi

What stain is used for medically important fungi? a. Methylene blue b. Acridine orange c. Lactophenol cotton blue d. Acid-fast

c. Lactophenol cotton blue

In the medical microbiology laboratory, the ability of a gram-negative bacterium to ferment this sugar is the first step in its identification. a. Sucrose b. Mannitol c. Lactose d. Trehalose

c. Lactose

When performing a Gram stain on a gram-negative organism, the crystal violet is absorbed into this outer cell wall layer, and then washed away with the acetone alcohol. What is the main component of the outer layer of the cell wall? a. N-acetyl-D-muramic acid b. Peptidoglycan c. Lipopolysaccharide d. Mycolic acid

c. Lipopolysaccharide

What type of fermentation produces lactic, acetic, succinic, and formic acids as the end products? a. Butanediol b. Propionic c. Mixed acid d. Homolactic

c. Mixed acid

Which of these bacteria cannot grow in the presence of oxygen? a. Capnophilic organisms b. Obligate aerobes c. Obligate anaerobe d. Facultative anaerobes

c. Obligate anaerobe

This constituent of a gram-positive cell wall absorbs crystal violet but is not dissolved by alcohol, thus giving the gram-positive cell its characteristic purple color. a. Carbolfuchsin b. Cholesterol c. Peptidoglycan d. Mycolic acid

c. Peptidoglycan

Diabetics may sometimes be infected with their own resident flora. This type of infection is called a. symbiosis. b. a carrier state. c. an opportunistic infection. d. a parasitic infection.

c. an opportunistic infection.

To survive, microbial inhabitants have learned to adapt by varying all of the following, except a. growth in all atmospheric conditions. b. growth rate. c. bacterial shape. d. growth at particular temperatures.

c. bacterial shape.

All the following are types of media, except a. transport. b. differential. c. fastidious. d. selective.

c. fastidious.

The nuclear membrane in prokaryotes is a. a lipid bilayer membrane. b. a classic membrane. c. missing. d. impenetrable.

c. missing.

The function of a cell wall is to a. regulate the transport of macromolecules in and out of the cell. b. provide reserve energy to the eukaryotic cell. c. provide rigidity and strength to the exterior of the cell. d. protect the eukaryote from predators.

c. provide rigidity and strength to the exterior of the cell.

Bacterial species that exhibit phenotypic differences are considered a. biovarieties. b. phagevarieties. c. subspecies. d. serovarieties.

c. subspecies.

Diphtheria is a disease produced by Corynebacterium diphtheriae. However, not all C. diphtheriae bacteria produce the toxin that causes this disease. To produce the toxin, the bacteria must first become infected with a bacteriophage. The process by which bacterial genes are transferred to new bacteria by the bacteriophage is called a. conjugation b. transformation c. transduction d. replication

c. transduction

A microorganism that is a unicellular organism and lacks a nuclear membrane and true nucleus belongs to which classification? a. Fungi b. Parasite c. Algae d. Bacteria

d. Bacteria

This bacterial state occurs when a host harbors a disease-causing organism, but does not show signs of disease a. Resident b. Indigenous c. Transient d. Carrier

d. Carrier

Name the numerous short (3 to 10 μm) projections that extend from the cell surface and are used for cellular locomotion. a. Flagella b. Phospholipid c. Mitochondria d. Cilia

d. Cilia

What process involves transferring or exchanging genes between similar regions on two separate DNA molecules? a. IS element b. Transcription c. Replication d. Recombination

d. Recombination

All of the following statements are true about viruses, except: a. Viruses are acellular but are surrounded by a protein coat. b. Viruses consist of DNA or RNA but not both. c. Viruses can infect bacteria, plants, and animals. d. Viruses do not need host cells to survive and grow.

d. Viruses do not need host cells to survive and grow.

The three regions of the lipopolysaccharide include all the following, except a. antigenic O-specific polysaccharide. b. core polysaccharide. c. endotoxin (inner lipid A). d. mycolic acid.

d. mycolic acid.