Chapter 6 Mastering Microbiology

Nitrogen is a growth-limiting nutrient for many organisms because it is necessary for the biosynthesis of amino acids. it is required for synthesis of nucleotides. it is required for lipid synthesis. only a small number of bacteria are able to extract it from the atmosphere. only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis.

At temperatures higher than the maximum growth temperature for an organism, hydrogen bonds within molecules are broken. membranes become too fluid for proper function. proteins are permanently denatured. hydrogen bonds are broken and proteins are permanently denatured. hydrogen bonds are broken, proteins are denatured, and membranes become too fluid.

In the process of ________ microbes detect the presence and density of other microbes and modify their metabolic activity in response. synergy quorum sensing symbiosis mutualism antagonism

A microorganism found living under conditions of high ________ is a barophile. carbon dioxide levels hydrostatic pressure oxygen concentrations pH values salt concentrations

A clinical sample labeled as "sputum" was collected from the blood. the skin. the lungs. a piece of tissue. the central nervous system.

What does halophilic mean? It means the organism grows well in an acidic environment. It means the organism grows at body temperature. It means the organism is "salt loving". It means the organism's colonies are yellow in color.

What does the term facultative anaerobe mean? Facultative anaerobes require oxygen for growth. Facultative anaerobes can grow with or without oxygen. More growth is evident when oxygen is present. Facultative anaerobes cannot grow in the presence of oxygen. Facultative anaerobes will only grow in the presence of nitrogen gas.

What does the term mesophile mean? Mesophiles grow well at 85 degrees Celsius. Mesophiles grow well at body temperature. Mesophiles grow well at 55 degrees Celsius. Mesophiles grow well at refrigerator temperatures.

Which organism is most likely to be responsible for the boils? Bacillus cereus Escherichia coli Staphylococcus aureus Staphylococcus epidermidis

What is a boil? A boil is a flat, red rash affecting a great portion of skin surface area. A boil is a painful, raised, red rash affecting a great portion of skin surface area. A boil is a series of clear fluid-filled blisters. A boil is a red lump in the skin that may be warm and painful to the touch. It is a localized accumulation of pus and tissue debris.

During which growth phase are bacteria more susceptible to antimicrobial drugs? lag phase stationary phase death phase log phase The susceptibility is the same for all phases.

What results when a single bacterium reproduces? One parent cell and a genetically different cell Two genetically identical daughter cells One parent cell and a genetically identical daughter cell Two genetically unique daughter cells

If you begin with six cells, how many cells would you have after three rounds of division? Twelve cells Nine cells Eighteen cells Twenty-four cells Forty-eight cells It is impossible to determine.

Which of the following is NOT a step in bacterial cell division? Replication of the genetic material Disappearance of nuclear envelope Splitting apart of two new daughter cells Cell elongation

Which step of binary fission is the reason for genetically identical daughter cells? Splitting of the two daughter cells There are four new daughter cells that result from one parental cell Elongation of the cell Replication of the bacterial chromosome

Crenation can result from a change in which of the following? pH osmotic pressure hydrostatic pressure temperature

Which of the following is an example of a biofilm? bacteria growing in nutrient broth bacteria growing on nutrient agar bacteria growing in plaque bacteria present in the bloodstream

Which of the following bacteria have an affinity for the heart valves? Bordetella pertussis Staphylococcus aureus Streptococcus mutans Bacillus subtilis

Which nutrient is responsible for the development of cavities in teeth? sucrose sorbitol albumin cholesterol

Why is Daniel underweight? Daniel is not eating very much, because he likes scrambled eggs, which are high in fat. Daniel is not eating much, because it hurts to chew and swallow. Daniel is not eating much, because pudding is high in sugar. Daniel is not eating much, because candy is very filling.

Which of the following terms is likely to describe optimal growing conditions for Streptococcus mutans? halophile thermophiles mesophile psychrotroph

A microbe recovered from an environmental sample grows on a medium composed of agar and a mix of salts. The agar is not digested during incubation. The growth rate increases in high CO2 conditions. The organism is likely a(n) heterotroph. halophile. autotroph. chemotroph. The answer cannot be determined from the information provided.

A cell that uses an organic carbon source and obtains energy from light would be called a lithoautotroph. photoheterotroph. chemoautotroph. chemoheterotroph. photoautotroph.

A(n) ________ organism require(s) oxygen for growth. aerotolerant and an anaerobic aerotolerant obligate aerobic anaerobic facultative anaerobic

Human pathogens are classified as thermoduric. thermophiles. mesophiles. psychrophiles. hyperthermophiles.

The use of salt and sugar in preserving various types of foods is an application of which of the following concepts? hydrostatic pressure quorum sensing nitrogen fixation osmotic pressure pH

Microaerophiles are microbes that grow best at low hydrostatic pressure. oxygen levels. carbon dioxide levels. salt concentrations. pH values.

An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful? inoculation of a minimal medium broth inoculation of EMB plates incubation in an anaerobic culture system culturing on blood agar plates inoculation of cell cultures

In a microbiology laboratory, what does culturing mean? Culturing is the process of studying microbes from textbooks. Culturing is the act of producing media. Culturing involves growing microbes in the lab. Culturing involves sterilizing media in the laboratory.

What is the purpose of using the streak plate method? Streak plates lead a scientist toward a pure culture for identification or examination of a single bacterial strain. A streak plate allows the scientist to study many microbes on one medium. The streak plate method will prevent any contamination of a culture. The streak plate method is a way of sterilizing media.

The goal of streaking for isolation is to spread an inoculum of bacteria thinner and thinner with each pass for the identification of individual colony-forming units. What action must be performed between each step to ensure this? An additional inoculum of bacteria must be added. Sterilization of the agar plate must be performed. The agar plate must be incubated overnight. Sterilization of the loop must be performed.

Partially digested yeast, which has varying chemical elements, is added to a medium that has been created with exactly measured ingredients. What type of media has been produced? complex media selective media differential media defined media

A medium designed to change color in order to indicate growth of certain types of bacteria would be considered a __________. selective medium defined medium complex medium differential medium

Why might a hospital choose to use transport media to carry clinical specimens? Transport media are designed to keep microbes stable until they can be inoculated into appropriate growth media. Transport media allow for long-term storage of microorganisms. Transport media enable the transporter to easily add more nutrients during transit. Transport media are designed to keep microorganisms growing during transport.

Because some target bacterial species are out-competed by others during growth on media, it is sometimes necessary to inhibit the growth of the competitors. What type of medium is specialized for this scenario? complex media defined media selective media differential media

What is a colony-forming unit? one or more cells that give rise to an assemblage of identical cells a single agar plate with various different species of microorganisms a type of media that allows only one type of bacteria to grow a unit of measure equal to the mass of one bacterium

Why would a particular microbe need to be cultured inside an animal? Standard laboratory culture techniques have proven inadequate. The microbe can grow slower inside an animal. It allows researchers to simultaneously observe the pathogenic effects of the microbe. The microbe becomes more pathogenic when grown inside a live animal host.