Microbiology Lecture and Lab Midterm Review
Describe the function of the indicator, neutral red, when the bacteria growing on MacConkey media ferment lactose.
the indicator will change from colorless to pinkish
Which of the following is a carbohydrate substance that encourages bacterial adhesion to host tissues?
Glycocalyx
Which of the following suggests mitochondria evolved from prokaryotic ancestors?
70S ribosomes
Bacterial capsules __________.
allow for avoidance of phagocytosis
A protein's ______________ structure requires the presence of more than one polypeptide chain.
quaternary structure
Infectious disease commonly follows five basic stages. During which stage would a patient not be able to spread the disease?
A patient may spread an infectious, communicable disease during any of the five stages.
Which of the following statements about ATP is false?
ATP can be stored in large amounts in a cell.
Which of the following features of Salmonella prevent it from being phagocytosed?
Flagella
The 80S ribosome is composed of each of the following except:
30S subunit
When would endotoxins be released from a bacterial cell?
When the cell dies
Which of the following is a correctly written version of a scientific name?
E. coli
Septic shock is typically associated with
Gram-negative infections.
Where is the site of Shigella attachment in the host?
M cells
Which of the following would be considered a symptom?
Nausea
Which of the following is not a functional group?
R-H
Primase lays down a short piece of __________ as a primer to start DNA replication.
RNA
Which of the following molecules is a defining characteristic of a ribozyme?
RNA
Glycolysis literally means
Sugar splitting
In DNA replication, Okazaki fragments are required in synthesizing __________.
The lagging strand, because the DNA polymerase can move only in the 5' to 3' direction
What is the role of epidemiology?
To learn how to treat and prevent various diseases.
Which of the following lipids tends to be liquid at room temperature? a. Unsaturated lipids b. Waxes c. Saturated lipids d. Fats
a. Unsaturated lipids
T/F: Agar is used as a solidifying agent for bacterial culture.
True
Who was the first person to recommend hand washing to reduce mortality rates?
Ignaz Semmelweis
Where do Salmonella pathogens grow and replicate in the infected host?
Inside phagocytes
Fungal infections are called...
Mycoses
Chemoorganoheterotrophic aerobes produce most of their ATP via electron transport with oxygen as the terminal electron acceptor. Which of the following carries electrons during aerobic respiration in chemoorganoheterotrophs?
NADH
A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)
Neurotoxin
Which of the following pH classifications make up most of the pathogens we know today?
Neutralophiles
Which of the following microbes would most likely be able to infect a deep wound on a patient?
Neutralophilic mesophiles
An isotope of an element has a different number of ________.
Neutrons
Which route of entry occurs when microbes enter the body through bites, cuts, injections, or surgical incision?
Parenteral
Which of the following techniques is the best way to directly count viable cells?
Plate counts
The role of transcription factors is to signal __________.
RNA polymerase to the promoter region of the intended gene to be transcribed
Viruses which infect many different tissues types are said to have a(n) a. Broad host range b. Indeterminate host range c. Narrow host range d. Broad tropism e. Narrow tropism
d. Broad tropism
____________ are organic or inorganic substances that increase the rate of a reaction but are not used up in the reaction. a. Vitamins b. Products c. Reactants d. Catalysts
d. Catalysts
Which of the following prion diseases may be acquired by eating beef contaminated with a cattle prion? a. Gerstmann-Straussler-Schienker syndrome b. Sporadic CJD c. Iatrogenic CJD d. Variant CJD e. Inherited CJD
d. Variant CJD
Tuberculosis is an example of a(n) __________ disease.
reemerging
What are the nutrient requirements for an organism classified as a photoautotroph?
sun and CO2
________________ cause(s) a massive immune response that can destroy immune cells by overstimulation.
superantigens
Which of the following is an indirect cell-counting method?
turbidity measurement
Which of the following is used in photosynthesis by both plants and cyanobacteria?
Water, sunlight, and carbon dioxide
What is the average net gain of ATP produced in fermentation?
1 to 2 ATP molecules
Which of the following would be considered a vector?
A fly carrying disease from fecal matter to food
Mitosis is characterized by
Genetically identical cells
The immediate result of electron movement through the electron transport chain is the pumping of protons across the bacterial cell membrane, creating a _____ outside the cell than inside the cell.
higher concentration of protons
Cytopathic effects induced by a virus include __________.
hijacking cellular machinery and disrupting normal host cell function
Bacteria used to make yogurt produce lactic acid only as a byproduct of fermentation. These organisms are said to use _________.
homolactic fermentation
Which of the following factors does not affect the efficiency of a germicide?
how the object is used
A micelle forms in water when the __________ component of the molecule is forced to the center of the structure.
hydrophobic
Septic shock is characterized by:
hypotension, tachycardia, and organ failure.
Most polyhedral viruses have 20 triangular-shaped sides and are called ____________.
icosahedral
Adhesins
include molecules that bind to host factors such as fibronectin, sialic acid, and heparin / heparin sulfate.
What is the order of the five stages of infectious disease?
incubation period, prodromal phase, acute phase, period of decline, convalescent phase
The selective & differential media called MAC contains a chemical called neutral red that will detect a change in pH if the sugar in the media is metabolized by the growing organism. What is the general term for the chemical added to media that detect changes in pH?
indicator
Carbonic anhydrase is an enzyme that solubilizes carbon dioxide so that it can be removed from human tissues. Structural studies have shown that a zinc ion is required at the active site in order for the enzyme to function. In this example, zinc is best described as a(n) _____ that is required to form the functional _______ .
inorganic cofactor; holoenzyme
Which process of glucose catabolism doesn't generate ATP?
intermediate step
In eukaryotic mRNA, there are sequences of mRNA that do NOT encode for specific amino acids and do NOT contribute to the protein. These sequences are called __________.
introns
You are a manufacturer of polypropylene hypodermic syringes. Which of the following methods would be best for ensuring sterility of this heat-sensitive material?
ionizing radiation
Gluconeogenesis
is building glucose from non-sugar starting materials and can be accomplished by funneling intermediates from glycolysis, the Krebs cycle, and lipid or protein catabolism and an example of biosynthesis.
In an evolutionary sense, a "successful" pathogen is one that:
is minimally symptomatic.
What is the function of eosin and methylene blue in EMB media?
it functions in both the selection of gram-negative organisms and the differentiation between lactose fermentors and non-lactose fermentors
Pathogens can hide in host cells, so host immune defenses don't detect them. They can remain undetected by remaining in a state of inactivity called _____________.
latency
When a healthcare provider diagnoses a reportable disease, who do they document the case with?
local public health authority
A health department technician takes a sample of water from a hot tub back to the lab to identify the microbe(s) present. If the technician runs biochemical tests, then they must use bacteria in their healthiest state. Which growth stage is usually ideal for this purpose?
log phase (exponential growth)
The main function of the Krebs cycle during cellular respiration is to ______.
make NADH and FADH2 through redox reactions
Which of the following does not describe cellular respiration?
may include multiple pathways including glycolysis, an intermediate step, the Krebs cycle and fermentation
Which of the following terms is likely to describe optimal growing conditions for Streptococcus mutans?
mesophile
Which temperature group are most pathogens associated with?
mesophiles
Examples of healthy host-microbe interactions with our normal microbiota include all except
microbiota disruption.
Besides biochemical tests, which techniques are also useful for identifying a bacterial specimen?
microscopy and molecular genetics techniques and observation of general culture characteristics
The enzymes superoxide dismutase and catalase work together to convert reactive superoxide ions back to _________.
molecular oxygen
A __________ is formed when two or more atoms of the same or different elements are bonded together.
molecule
During the Ebola outbreak between 2014 and 2016, according to the CDC an estimated 29,000 cases of Ebola were reported. About 12,000 people died. Therefore, the _________ rate was about 41%.
mortality
The __________ in acid-fast bacterial cell walls retain the carbol fuschin in the Ziehl-Neelsen acid fast staining method.
mycolic acid
This image shows the results of three different bacterial species grown on MacConkey. All three organisms have grown on the media. Which organism(s) is/are gram-positive?
none
•An organism is inoculated on an MSA plate. After incubating the plate to allow for bacterial growth, no growth is observed. Why didn't the bacteria grow on MSA?
not halophilic
Iron-binding proteins are examples of virulence factors that permit ___________.
nutrient acquisition
Organisms that have an absolute dependence on abundant oxygen for cellular processes are __________.
obligate aerobes
You have counted 38 bacterial colonies on the surface of a petri dish and recorded the number in your lab notebook. This is an example of a(n) __________.
observation
Of the following, which would be considered a biochemical test?
observing a change in pH after the breakdown of a substrate
In an operon, the repressor binds to the _______.
operator
Which term represents the temperature that bacteria grow the fastest at?
optimal
This image shows the results of three different bacterial species grown on EMB. All three organisms have grown on the media. What does the appearance of the growth of organism "C" indicate?
organims "C" exhibited an abundance of lactose fermentation resulting in a metallic sheen
•In a redox reaction, the molecule that loses an electron is _______ and the molecule that gains the electron is _______.
oxidated, reducted
Sugar molecules, such as glucose, are _________ during the first steps of energy harvest for a cell.
oxidized
Which portal of entry is mismatched to its description?
parenteral: pathogen is passed from mother to child through the placenta
Infectious mononucleosis is spread through kissing or other close contact between the host and a healthy individual. This is considered _________.
person-to-person transmission
Which functional group is found at the 5' end of DNA?
phosphate group
ATP is produced during a process called _______.
phosphorylation
An organism that harvests sunlight for energy and requires an external source of organic carbon in its metabolism is characterized as a _________.
photoheterotroph
•The reactions of the electron transport system occur in the ________of prokaryotic cells and in the ________ of eukaryotic cells.
plasma membrane, mitochondria
The sequence of amino acids that make up a protein are known as the ____________ structure.
primary
Early symptoms develop during the __________ of infectious disease.
prodromal phase
Many food spoilage bacteria are characterized by temperature as ___________.
psychotroph
Listeria monocytogenes can grow slowly in your refrigerator, with its optimum temperature range between 30 to 37°C. This organism is characterized as a __________.
psychrotroph
Listeria monocytogenes grows best at refrigerator temperatures and is therefore considered a _________.
psychrotroph
Many food spoilage bacteria are characterized by temperature as ___________.
psychrotrophs
The presence of specific ___________ on viruses determine whether it can infect a particular cell or not.
receptors
The animate or inanimate habitat where an infectious agent is usually found is the _________.
reservoir
Adding oil to the slide when using the 100X objective improves the ________ of the image.
resolution
Sneezing, coughing, and mucus drainage are pathogen transmission source from which portal of exit?
respiratory
cDNA is a product of the action of __________.
reverse transcriptase
RNA nucleotides are made of a sugar, a phosphate, and a nitrogen base. Which sugar is unique to RNA nucleotides and NOT found in DNA nucleotides?
ribose
Exotoxins are
secreted and only made by Gram-positive bacteria.
EMB media is a selective and differential diagnostic media. What does EMB select for? What does it differentiate?
selects for gram-negative organisms and differentiates between organisms that can or cannot ferment lactose
MacConkey media is a selective and differntial diagnostic media. What does MacConkey select for? What does it differentiate?
selects for gram-negative organisms and differentiates between organisms that can or cannot ferment lactose
There are two nonstandard encoding amino acids: __________.
selenocysteine and pyrrolysine
You suspect that your patient has a urinary tract infection caused by Proteus vulgaris, a motile bacterium with peritrichous flagella. Which of the following physical states of media is best for observing motility of this pathogen once isolated?
semisolid deep
The role of healthcare workers in the management of disease outbreaks
should be addressed through periodic training and re-training.
The health of the patient
should be the primary concern of the healthcare worker.
The red arrows are pointing to _________________.
single bacterial colony
Bacillus subtilis is naturally found in the soil. B. subtilis is known to contaminate rice, which, if undercooked and ingested, can lead to gastroenteritis. In this example, the reservoir for B. subtilis is the ________, and the source of infection is the ___________.
soil; rice
During the __________ phase of bacterial growth in a closed system, the number of cells dying equals the number of cells dividing.
stationary
In which growth phase do bacteria produce antibiotics and endospores?
stationary phase
Refer to the numbered steps in the figure when answering the question. Which step is a redox reaction?
step 6
A genetic variant of a bacterium is known as a __________.
strain
•What type of phosphorylation is used to produce ATP in the Krebs cycle?
substrate phosphorylation
Glycolysis makes ATP using ______.
substrate-level phosphorylation
Measles viruses are capable of inactivating host defenses by
suppressing the immune system.
This image shows the results of different bacteria inoculated onto an EMB plate. What does the metallic green-colored growth indicate?
the bacteria are gram-negative lactose fermentors
An organism is inoculated on an MSA plate. After incubating the plate to allow for bacterial growth, no growth is observed. Why didn't the bacteria grow on MSA?
the bacteria couldn't grow in the presence of high salt concentrations
The term used by molecular biologists to describe the flow of genetic information from DNA, to RNA, to protein is __________.
the central dogma of biology
Describe the function of the indicator, neutral red, when the bacteria growing on MacConkey media ferment lactose
the indicator will change from colorless to pinkish
ID50 describes
the number of cells or virions needed to establish an infection in 50 percent of exposed hosts.
An organism is streaked onto MSA and allowed to grow overnight at 37º C. The plate has bacterial growth, but the media remained a pinkish color. What do the results indicate about the organism?
the organism can grow in high salt conditions, but cannot ferment mannitol
In the typical ATP-ADP cycle, which part of the ATP molecule is removed when energy is released and added back when energy is stored?
the terminal phosphate group
A _________ explains how and why something occurs.
theory
The minimum temperature needed to kill all microbes in a sample within ten minutes is called the
thermal death point.
Biochemical tests are useful to microbiology because
they can be used to identify microbes and to identify potential pathogens in clinical samples and they can be used to detect metabolic end-products, intermediates, or particular enzymes.
Epidemiological measures are useful tools because:
they help determine which diseases may need greater public health campaign or prevention efforts.
Lyme disease is spread _________.
through biological vectors
What is the purpose of the streak plate technique?
to obtain a pure culture from a mixed or unknown source
When toxins enter the host's bloodstream, the resulting condition is called ____________.
toxemia
Which type of bacterial toxin is matched incorrectly with its description?
toxemia: a toxin produced during a viral infection
•Superantigens made by certain Streptococcus and Staphylococcus species can cause ___________ (2 words) syndrome.
toxic shock
If a bacterial cell with an intact cell wall is placed in a hypertonic solution it will____________.
undergo plasmolysis.
Organisms that are adapted to survive in cold temperatures have a higher proportion of __________ in the lipid bilayer.
unsaturated fatty acids
Retroviruses produce mRNA by:
using reverse transcriptase to convert single- stranded RNA (ssRNA) to double-stranded
Which mode of transmission is not addressed by transmission precautions?
vector
When a sheep's blood agar plate is streaked with bacteria, such as Streptococcus pyogenes, beta hemolysis occurs. What does beta-hemolysis indicate about the pathogenicity of S. pyogenes?
very pathogenic, destroys red blood cells
A __________ is a single particle made up of genetic material encased in a protein shell.
virion
When would a microbiologist want to use broth media?
when growing large batches of microbes
When would a microbiologist use thioglycolate?
when storing plates anaerobically
Toxemia is a condition
where a toxin has entered the bloodstream resulting in systemic effects.
Epidemiology is defined as the study of
where and when a disease occurs, and how it is transmitted.
Which of the following infectious disease transmission modes is not correctly paired with an example?
windborne: cholera
Proteins provide cells with the necessary equipment to perform normal cellular activity. Without gene expression the cell __________.
would die
Which of the following suffixes would be used to describe a viral family?
-viridae
The size of most prokaryotes is between:
0.5 and 2.0 μm.
Refer to the numbered steps in the figure when answering the question. Which step shows an energy investment in the form of ATP?
1 and 3
Which of the following toxin properties belong to exotoxins? [make sure that you can identify the properties of endotoxins also] made of protein made exclusively by gram-negative bacteria cannot be neutralized in patients typically produce fevers released exclusively from actively growing bacteria
1,5
Spontaneous mutations are estimated to occur in one out of every _______ base pairs.
10^10 (10 billion)
The ID50 for inhalational anthrax is 11,000 endospores. Based upon this information, choose the true statement.
11,000 endospores must be inhaled to establish an infection in 50 percent of susceptible hosts.
In an experiment to calculate the decimal reduction time for an Escherichia coli culture, viable cells were exposed to a constant temperature of 80°C for a set amount of time. After exposure, the remaining number of surviving cells were counted. Based on Table 1, what is the decimal reduction time? Table 1. Decimal Reduction Time for E. coli Heated to 80°C
13 mins
How many codons code for the amino acid histidine?
2
How many net ATPs can be made from one molecule of glucose in glycolysis?
2
•How many acetyl CoA molecules are produced during the intermediate step from 1 molecule of glucose?
2
•How many pyruvic acid molecules are produced from the glycolysis of 1 glucose molecule?
2
You calculated the generation time of a strain of Pseudomonas aeruginosa as 40 minutes. How long would it take (in hours) for three generations to grow?
2 hours
Put the following steps of bacterial replication in the correct order, starting from a parent cell. 1. Cell elongation 2. Septum formation 3. Chromosome replication 4. Separation of daughter cells
3, 1, 2, 4
Your initial inoculum was 200 cells. How many cells would be present after 2 hours if the generation time was 30 minutes?
3,200 cells
Part complete The following table shows the generation time for an Escherichia coli culture grown at various incubation temperatures. Table 1. Incubation Temperature and Corresponding Generation Times of E. coli Table 1 shows the generation time for Escherichia coli at various temperatures. At 5℃ and 60℃ , the culture does not grow. At 7℃, the generation time is 40 minutes, at 37℃, the generation time is 20 minutes, and at 42℃ , the generation time is 35 minutes. According to the table above, the optimal growth temperature for E. coli is:
37C
At which temperature would you expect enzymes and proteins of human pathogens to denature?
41°C
What is a boil?
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.
Which of the following is an example of catabolic and anabolic reactions working together?
A cell breaks down a polysaccharide to produce ATP, which is then used to build a polypeptide molecule.
The chromatin is...
A collection of DNA and protein
Hyphae are...
A collection of tubular structures that result from fungal growth
What is the primary difference between a disinfectant and an antiseptic?
A disinfectant is used to decontaminate lifeless objects, whereas an antiseptic is applied to living tissue.
Which of the following is the best definition for the term attenuated?
A microorganism that is infectious but is weakened to the point of being unable to cause disease in an immunocompetent host
A healthy gut microbiome contains diverse species where benign microbes help keep pathogenic members in check. Which of the following could tip the balance from normal microbiota to a disease state?
A patient on an intravenous course of antibiotics
A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n) enterotoxin. membrane disrupting toxin. superantigen. cytotoxin.
A superantigen
Which energy-rich molecule directly powers cell work?
ATP
Which energy-rich molecule directly powers cell work?
ATP (B)
Which of the following describes primary active transport?
ATP is used to drive transport.
Why is ATP required for glycolysis?
ATP makes it easier to break apart glucose into two three-carbon molecules
Why is ATP required for glycolysis?
ATP makes it easier to break apart glucose into two three-carbon molecules.
What is the intermediate product formed by pyruvic acid during alcoholic fermentation?
Acetaldehyde
Why is it so difficult to kill acid-fast bacteria?
Acid-fast bacteria have mycolic acid in their cell walls, which limits drug entry
•In what type of conditions would you expect to find a halophilic acidophile
Acidic conditions pH 1 2
Which of the following is NOT a way that pathogens cause host immunosuppression?
Activation of memory cells
Which is the key difference between aerobic and anaerobic respiratory chains?
Aerobic respiratory chains always use oxygen as the final electron acceptor while anaerobic respiratory chains may use a variety of inorganic substances other than oxygen as the final electron acceptor.
Alanine is a non-essential amino acid in humans. Based on this, select the true statement about alanine.
Alanine is made in human cells as the result of an amination reaction.
Avoidance of killing is a mechanism that microbes employ to survive in a host cell. Which of the following ways can microbes avoid being killed inside of a host cell? [Choices: surrounding itself with a vacuole to avoid host lysosomes; avoiding host lysosomes by escaping into the cell's cytoplasm; avoidance of lysosome binding to the pathogen; all of the answers are correct]
All of the answers are correct
Viral spikes
Allow the virus to attach and enter host cells, may be a target for the host immune system, and show specificity in binding to particular structures on the host cell
Which of the following is the product of transcription?
An RNA sequence
__________ is the preferred microbial media format for isolating individual bacterial colonies.
An agar plate
An anion is formed when...
An atom gains one or more negatively-charged electrons
Which of the following is an example of a direct contact transmission?
An individual contracts rabies after being bitten by a rabid raccoon.
Which of the following would be considered a fomite?
An infected toy
New and reemerging diseases are being identified by physicians. Name five causes that can lead to new and reemerging diseases.
Antibiotic resistance: Changes in organisms genotype and phenotype (antigen shift/drift) Expanded host tropism: "species jumping" Travel: new organisms introduced from other countries Not vaccinating children: causing reemerging diseases such as whooping cough, measles...
Clostridium difficile causes severe diarrhea. Many times proliferation of this microbe in the gut is associated with the overuse of _____________.
Antibiotics
How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?
Antibiotics can be used in aerosols, thereby entering the environment.
•Most extremophilic organisms belong to the domain __________.
Archaea
Bacteriophages use different mechanisms for host cell infection and viral replication. During the lytic replication pathway, bacteriophages infect the host bacterial cells and immediately build new virions. During which of the key steps is the genome packed into capsid and phage structures put together?
Assembly
Which of the following methods uses steam-heat and pressure to effectively sterilize microbiological media and equipment?
Autoclaving
You would like to sterilize bacterial growth media in a flask. You have about 1.5 hours before your patient's sample will be ready for inoculation. Which method would be best to sterilize the media within the timeframe?
Autoclaving
Quorum sensing allows bacteria within communities to communicate with chemical messages, which may help regulate gene expression. The chemical messages are called __________.
Autoinducers
Bacillus anthracis, like other Bacillus species, are Gram-positive bacteria that produce endospores. Samples were taken from infected patients and stained as indicated. Which of the following show a sample that contain endospores?
B
Legionella is a Gram-negative, pleomorphic bacterium that is an obligate aerobe. After sampling various water sources, the following results were obtained. Based on the data below, which water source(s) is (are) contaminated with this microorganism?
B
Which organism(s) ferment(s) lactose?
B and C
Which domain of the A-B toxin binds to cell surface receptors on the host cell?
B domain
Most hospitals and microbiology teaching laboratories maintain _________ standards.
BSL-2
Which biosafety level is incorrectly matched with its description?
BSL-2+: known animal pathogens which do not infect humans
A patient infected with a multi-drug resistant strain of Mycobacterium tuberculosis would be cared for in a __________ facility.
BSL-3
Which of the following organisms is not an opportunistic pathogen?
Bacillus anthracis
All of the following spore-forming bacterial species cause disease except:
Bacillus subtilis.
What type of nosocomial infection is likely to arise from intravenous catheterizations?
Bacteremia
Which of the following best describes how bacterial growth in nature is different from growth in a laboratory setting?
Bacteria tend to grow as a mixture of species in biofilms in nature.
Which of the following methods is used to cultivate bacteriophages in the laboratory setting?
Bacteriophages are cultivated in bacteria in liquid broth or on solid medium
A patient presents with symptoms of severe gastrointestinal distress. Bacterial and viral pathogens are ruled out. A protozoan which moves via hair-like appendages is observed upon microscopic examination of the patient's stool. The most likely cause of the infection is a. Crytposporidium parvum, an apicomplexan b. Balantidium coli, a ciliated protozoan c. Plasmodium, an apicomplexan d. Ergot toxin, a fungal mycotoxin e. Entamoeba histolytica, an amoeboid protozoan
Balantidium coli, a ciliated protozoan
After growing an organism on sheep's blood agar, you observe complete clearing surrounding bacterial growth. This indicates that the organism is ______ hemolytic.
Beta
Streptococcus pyogenes, the etiological agent of strep throat, scarlet fever and rheumatic fever, exhibits complete clearing of RBCs when grown on sheep's blood agar. What type of hemolytic pattern does this indicate?
Beta
Prokaryotes reproduce via _________.
Binary Fission
Which of the following is a key distinguishing characteristic between budding and binary fission?
Binary fission results in daughter cells of equal size, whereas budding is an uneven division
Which of the following is not a role of the eukaryotic glycocalyx?
Biofilm production.
Choose the false statement about biofilms.
Biofilms are easily treated using antibiotics.
Which of the following is not a mechanism of an antiviral drug?
Blocking viral ribosomes
Both Vibrio cholerae and Salmonella typhi are capable of causing disease inside of otherwise healthy individuals. The ID50 of V. cholerae is 1,000,000 cells, while the ID50 of S. typhi is 10,000 cells. Based on this information, which of the following statements is true?
Both V. cholerae and S. typhi are pathogenic, but S. typhi is more virulent than V. cholerae.
Choose the false statement about buffers:
Buffers may cause alkalosis.
Why are diabetics at risk for wound infections by anaerobic bacteria like Clostridium perfringens?
C. perfringens colonizes unhealthy tissues that do not receive enough oxygen, and diabetics have difficulty transporting oxygen to body tissues, especially in the extremities.
Which of the following might be used by a chemoorganoheterotroph for energy?
C6H12O6
Genes can be silenced by a process called DNA methylation. Which of the following compounds is a methyl group?
CH3
Which of the following correctly describes the molecular formula for methane, which is comprised of one carbon atom and four hydrogen atoms?
CH4
Which of the following are examples of endogenous sources of transmission?
Candida albicans (pathogenic strain of yeast)
Candida albicans can thrive in the absence of oxygen, so how can it also grow in the human mouth?
Candida is a facultative anaerobe.
The protein shell that packages and protects the genome and also accounts for the bulk of a virion's mass is called a _________.
Capsid
How can capsules enable bacteria to evade the immune system?
Capsules block the complement biding sites on the surface of the pathogen.
Which of the biomolecules is incorrectly matched with its building block? a. Carbohydrate: Polysaccharide b. Lipid: Fatty acid c. Lipid: Glycerol d. Nucleic acid: Nucleotide e. Protein: Amino acid
Carbohydrate: Polysaccharide
Of the following, which does NOT occur in the Krebs cycle?
Carbon molecules are reduced and the electron carrier molecules are oxidized.
When we say that catabolic and anabolic reactions are coupled, what does that really mean?
Catabolic reactions provide energy and smaller molecules required by anabolic reactions.
1) The biochemical test shown in the image is used to detect the presence or absence of a certain enzyme that differentiates staphylococci (positive) from streptococci (negative). Using your knowledge of the test and the results observed in this image, name the enzyme.
Catalase
The biochemical test shown in the image is used to detect the presence or absence of a certain enzyme that differentiates staphylococci (positive) from streptococci (negative). Using your knowledge of the test and the results observed in this image, name the enzyme.
Catalase
Which of the following is not a factor that influences enzyme activity?
Catalysts
Cell shape is determined by which of the following?
Cell wall and cytoskeleton components
Which organelle builds microtubules?
Centrosome
Which of the following describes conidiospores?
Chains of spores not enclosed in a sac.
•A certain species of bacteria grows the best on 5% peptone, 5% beef heart extract, and 8% sodium chloride. From this description, identify this general type of growth media.
Chemically complex media
A certain species of bacteria grows the best on 25% glucose, 5% NaCl, and 0.2% magnesium sulfate agar plates. From this description, identify this general type of growth media.
Chemically defined
Which of the following is the most common healthcare-acquired infection (HAIs)?
Clostridium difficile infections
Which of the following key HAI's is not associated with its correct cause?
Clostridium difficile: Causes acute illness that is followed by a high risk of chronic infection that causes severe liver damage and increases the risk of liver cancer
A key test used to differentiate Staphylococcus aureus from Staphylococcus epidermidis relies on the microorganism's ability to clot blood plasma fibrin. Based on this information, this distinguishing assay tests for the invasin
Coagulase
The biochemical test shown in the image is used to detect the presence or absence of a certain enzyme that distinguishes between Staphylococcus aureus (positive) from other species of staphylococci (negative). Using your knowledge of the test and the results observed in this image, name the enzyme.
Coagulase
Which type of invasin is correctly matched with a representative organism?
Coagulase - Staphylococcus aureus
Which of the following is not involved in nutrient acquisition by an invading pathogen?
Coagulases
You are preparing a growth medium for an isolate that you obtained from a patient. You are adding yeast extract, glucose, peptones, malt extract, and ampicillin. Which kind of medium are you preparing?
Complex and selective
Which of the following is considered a major category of transmission of disease?
Contact, vehicle, and vector transmission
Which of the following describes the function of lysosomes?
Contain a wide variety of hydrolytic enzymes that break down substances engulfed by the cell.
The genetic code a. Uses a quartet code to encode the codons b. Relies on codons made up of DNA c. Contains sense codons and nonsense codons d. Has 60 codons e. Encodes for 18 amino acids
Contains sense codons and nonsense codons
Which microorganism requires the low pH inside a phagolysosome in order to reproduce?
Coxiella burnetii
The type of medical equipment that regularly comes into contact with sterile body sites or the vascular system and must therefore be sterilized is classified as _________.
Critical equipment
Which of the following is a bacterium that performs oxygenic photosynthesis?
Cyanobacteria
Where does glycolysis occur in prokaryotes and eukaryotes?
Cytoplasm
An exotoxin that has the ability to kill or damage host cells is referred to as a(n)
Cytotoxin
RNA primers are removed from the leading and lagging strand by __________.
DNA polymerase I
In DNA replication, what is the main enzyme responsible for adding complementary nucleotides to the daughter strand while reading the parent strand?
DNA polymerase III
The Endosymbiotic theory describes the evolution of eukaryotes occurred through the merging of each of the following except:
DNA virus
Which of the following macromolecules is incorrectly paired with its building blocks?
DNA: nicotinic acids
Why is Daniel underweight?
Daniel is not eating much, because it hurts to chew and swallow.
Which of the following is not a responsibility of epidemiologists?
Develop antibiotics
Which of the following factors allows for the best chance of disease eradication?
Disease is preventable through vaccination
_________ reduces the number of microbes on a given non-living surface of a sample.
Disinfection
Choose the false statement about bioremediation.
Dispersants are added so that the remediating microbes can grow
What is the definition of a true pathogen?
Does not require a weakened host to cause disease
Which of the following is the broadest taxonomic classification?
Domain
Which of the following statements correctly describes Dr. Ignaz Semmelweis's contribution to hospital epidemiology?
Dr. Semmelweis demonstrated that handwashing prior to examining patients cut down on the incidence of nosocomial infections.
You had dinner with your friend who was suffering from a severe cold. She sneezed a few times, and now you are worried that she transmitted her cold to you. During which of the five stages of disease would you expect first symptoms to appear?
During the prodromal phase
Which of the following is not an example of a virulence factor?
Dysbiosis
Many strains of E. coli are able to grow on minimal media which consists only of a single sugar, usually glucose, and inorganic salts to provide nitrogen, sulfur, phosphorous and trace nutrients. What does this tell you about E. coli's biosynthetic capabilities?
E. coli can funnel intermediates from glycolysis, the intermediate step, and the Krebs cycle to synthesize amino acids, fatty acids, glycerol, and nucleotides.
Which step in carbohydrate metabolism yields the most ATP?
ETS
Which is not an example of virulence as an evolving property?
Each of these is an example of virulence as an evolving property.
Which of the following does not rely on isotopes?
Electrolyte therapies
___________ are formed when ionic compounds dissolve in solution and have a role in regulating blood volume.
Electrolytes
During which step of cellular respiration is most ATP produced?
Electron transport chain
Which of the following processes occurs in the plasma membrane of a prokaryotic cell?
Electron transport chain
NADH and FADH2 play an important role in energy production by donating electrons for redox reactions in the ___________.
Electron transport system
Toxigenic gram-negative bacteria produce which toxin(s)?
Endotoxins and exotoxins
Why do all enzymatic reactions need activation energy?
Energy is required to disrupt a substrate's stable electron configuration.
What is the relationship between the ATP-ADP cycle and catabolic and anabolic reactions?
Energy released from catabolic reactions is used to recharge ADP back to ATP. Then the energy needed for anabolic reactions is released by breaking ATP down to ADP.
Zika virus is best described as a(n) _________ virus with a ________ genome.
Enveloped, ssRNA+
Choose the false statement about enzymes
Enzymes are used up in a reaction
Enzymes speed up the chemical reactions in living cells.
Enzymes decrease the amount of activation energy required for chemical reactions to occur.
Which of the following statements correctly describes enzymes?
Enzymes increase the reaction rate.
Which of the following is one way that enzymes decrease activation energy?
Enzymes stabilize the reaction's transition state.
Explain why low blood pH, like that seen in ketoacidosis, is potentially deadly.
Enzymes that are necessary for cells and tissue to function depend on an optimal body pH.
You would like to show the presence of Gram-negative lactose fermenters in your unknown pure culture. Which of the following media would be most appropriate?
Eosine methylene blue (EMB) agar
Even though the CFTR gene is in every cell of the body, only certain cells contribute to the CF phenotype due to CFTR mutations. Discuss a possible explanation for this.
Epigenetic modifications (such as DNA methylation) may silence production of the CFTR gene in certain cell types
Using your knowledge of organism's gram staining properties, which of the following organisms would grow on EMB?
Escherichia coli
Ethylene glycol is an ingredient in antifreeze. If antifreeze is swallowed, the enzyme alcohol dehydrogenase binds to the ethylene glycol and converts it to toxic oxalic and glycolyic acid. One of the treatments for ethylene glycol poisoning is the administration of the enzyme's natural substrate, ethanol. Based on this information, what is the best way to describe how ethanol protects against ethylene glycol poisoning?
Ethanol competes with ethylene glycol to limit oxalic and glycolyic acid formation.
Which of the following chemicals is applied as a gas to sterilize equipment and disinfect surfaces?
Ethylene oxide
Your patient is receiving a spinal fusion to correct a skeletal defect. Which of the following germicides is recommended to sterilize the bone used for the transplantation?
Ethylene oxide
Single colonies
Examples of single colonies of bacteria designated by the red arrows. The bacteria from a colony can be gram stained to determine the morphology, orientation, and whether the bacterium is gram-positive or -negative. Using this information, further diagnostic biochemical tests will be performed to positively identify the organism.
Toxigenic gram-positive bacteria produce which toxin(s)?
Exotoxin
You inoculate a semisolid thioglycolate medium with a pure culture of Staphylococcus aureus. You incubate the sample under optimal growth conditions (37°C). Following incubation, you observe heavy growth at the top of the tube and moderate growth near the middle and bottom portions of the tube. Based on this observation, Staphylococcus aureus would be best classified as a(n)?
Facultative anaerobe
What does the term facultative anaerobe mean?
Facultative anaerobes can grow with or without oxygen. More growth is evident when oxygen is present.
T/F: Bright field microscopy is great for seeing living samples.
False
T/F: Eukaryotes have a much simpler genetic makeup than prokaryotic cells.
False
T/F: Immunofluorescence is when fluorochromes bind to a specific target and fluoresce after exposure to UV light.
False
T/F: The primosome includes RNA polymerase to build the protein.
False
Which of the following statements about feedback inhibition is false?
Feedback inhibition is irreversible.
Rank the following metabolic strategies from least potential ATP gain to greatest potential ATP gain.
Fermentation, anaerobic respiration, aerobic respiration
Which of the following would be the first sign of an infection that resulted in the release of endotoxin?
Fever
How would Pseudomonas aeruginosa most likely adhere to the respiratory membrane of a patient in a ventilator?
Fimbriae
When an individual's CD4 T cell count drops below 200 cells per cubic millimeter of blood due to infection with Human Immunodeficiency Virus (HIV), an individual is diagnosed with Acquired Immune Deficiency Syndrome (AIDS). Your patient is at an advanced stage of HIV infection. Which of the following methods of cell enumeration would be most definitive for an AIDS diagnosis?
Flow cytometry
Which of the following is an example of dysbiosis?
Following extended use of amoxicillin, your patient develops oral thrush as a result of the overgrowth of Candida albicans.
Which of the following "germicides" should only be applied as a disinfectant?
Formaldehyde
Each of the following describes eukaryotic cilia except:
Found in both prokaryotes and eukaryotes.
Which of the following statements is true regarding hand washing?
Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction.
The core component of __________ cell walls is chitin.
Fungal
Group B Streptococcus (GBS) is considered a commensal organism in women, yet babies are susceptible to infection with GBS. All of the following are reasons why this occurs except:
GBS doesn't produce the same virulence factors in the baby as it does in in the mother.
Escherichia coli yields whitish colonies when grown on sheep's blood agar. What type of hemolytic pattern does this indicate?
Gamma
Which of the following is a common healthcare-acquired infection?
Gastrointestinal infection caused by Clostridium difficile
Which of the following diseases is noncommunicable, meaning that it is not spread from person to person?
Giardiasis
Standard precautions are used by healthcare providers when working with patients to protect themselves, and minimize the spread of infection. Which of the following precautionary measures is used as a contact precaution? [make sure that you can recognize airborne and droplet precautions]
Gloves
Pyruvic acid is utilized during various fermentation processes. What process produces the pyruvic acid that fuels fermentation? (Hint: see page 253, and Figure 8.23)
Glycolysis
Which of the following statements about glycolysis is true?
Glycolysis is also called the Embden-Meyerhof pathway.
Which of the following processes are likely utilized by an obligate anaerobe that generates energy through respiration and is not capable of fermentation?
Glycolysis, Krebs cycle, electron transport chain
Choose the single true statement about biological molecules:
Glycosidic bonds join the simple sugars in a carbohydrate.
Why are chemical agents like lysozyme more likely to damage Gram-positive bacteria than Gram-negative bacteria?
Gram-negative bacteria have an outer membrane as part of their cell wall
Which of the following statements correctly describes endotoxins?
Gram-negative bacteria mainly release endotoxin when they die, although a small amount can be released as the bacteria divide.
Choose the true statement about Gram-negative versus Gram-positive cells
Gram-negative cells are more resistant to penicillin-based drugs than Gram-positive cells
In which organism would you likely find a chlorosome?
Green sulfur bacteria
What is the purpose of having a high salt content in the diagnostic media, MSA?
Halophiles, selective
Which of the following describes zygospores?
Haploid gametes found at the tips of hyphae.
What are the four signs of inflammation?
Heat, pain, redness, and swelling
In DNA replication, what enzyme unwinds the DNA?
Helicas
Which of the following organisms would have enzymes that would function best in a low pH?
Helicobacter pylori
Which of the following pathogen agents is multicellular?
Helminths
Sheep's blood agar differentiates between bacteria that produce a toxin called __________, which is indicated by the partial or complete destruction of red blood cells contained in the media.
Hemolysin
Sheep's blood agar differentiates between bacteria that produce enzymes called __________, and bacteria that lack them. The presence of the enzyme results in partially or completely destroying red blood cells contained in the media.
Hemolysin
Which of the following is a characteristic of flatworms?
Hermaphroditic (and segmented)
List three ways that pathogens can hide from host immune defenses.
Hiding inside host cell Pathogen latency Antigenic masking, mimicry, and variation
Which of the following enzymes breaks down the "glue" that holds cells together?
Hyaluronidase
____________ do not bind atoms into molecules. Instead, they are non-covalent electrostatic attractions between two or more molecules or within a single large molecule.
Hydrogen bonds
Which of the following is not considered a chemical pathway?
Hydrolytic pathway
Tubular structures that form the structure of most fungi are __________.
Hyphae
According to the figure, when were measles the most prevalent in the US?
In the late 50s
Choose the true statement about a bacterial colony?
In theory a colony derives from a single cell.
Which of the following is not part of the epidemiological triangle?
Incidence rate
To maintain a fluid plasma membrane in cold conditions, bacteria may modify their plasma membranes by
Incorporating short unsaturated fatty acids into their membrane phospholipids
An operon that is transcribed in response to the presence of a substrate is called a(n) _______.
Inducible operon
List three ways that microbes cause host immunosuppression.
Interfering with phagocytosis immunosuppression certain microbes can undermine host defenses by interfering with molecular signaling that activates the immune response.
Pathogens can use collagenases, neuraminidases, and coagulases to invade host tissue. These molecules are collectively known as _____________.
Invasins
Which component of the light microscope modulates how much light is aimed at the specimen?
Iris diaphragm
_____________ are atoms with the same number of protons but a different number of neutrons.
Isotopes
Which statement is not true about the pentose phosphate pathway?
It allows cellular respiration to occur without the need for oxygen.
How does the protozoan Trypanosoma evade detection by the immune system?
It can change the surface antigens frequently, preventing the immune system from tracking it.
Why is a release of endotoxin into the bloodstream potentially deadly?
It can lower blood pressure and cause the patient to go into shock.
Julia has contracted Clostridium botulinum from a contaminated food source. What is the main reason that antibiotics should not be used to treat Julia?
It could have increased toxin release from the bacteria.
What is the function of a carboxysome?
It houses carbon-fixation enzymes
Which of the following statements about fermentation is true?
It is an alternative way to return electron carriers to their oxidized state.
Choose the single false statement about Mg2+ ?
It is an anion.
In many parts of the US, West Nile infections increase during the summer months. What is the reason?
It is transmitted by mosquitos, which are more prevalent during the summer months.
When a virus has an envelope, a. It likely escapes its host cell by budding. b. It is always an RNA-containing virus. c. It is always a bacteriophage. d. It may escape its host cell either by budding or by lysis. e. It likely escapes its host cell by lysis.
It likely escapes its host cell by budding
What does halophilic mean?
It means the organism is "salt-loving."
Which of the following best describes substrate level phosphorylation?
It occurs when an enzyme transfers a phosphoryl group from a donor substrate directly to ADP to make ATP.
Which of the following describes phosphotransferase systems?
It often involves group translocation through the use of phosphoenol pyruvate.
Choose the false statement about binary fission.
It produces daughter cells that are genetically unique from one another.
What is the fate of the NAD+ newly regenerated by fermentation?
It returns to glycolysis to pick up more electrons.
What is the role of pyruvic acid in fermentation?
It takes the electrons from NADH, oxidizing it back into NAD+.
Which of Koch's postulates involves isolating an organism from the diseased host and growing it in pure culture?
Koch's second postulate
•The majority of the high energy coenzymes (such as NADH and FADH2) are generated during which step of aerobic respiration?
Krebs cycle
•The virulence of a toxin is described by _________. [choices: ID50; LD50; VD50; TD50]
LD50
Your laboratory is working with Clostridium tetani, the etiological agent for tetanus. Which of the following minimum personal protective equipment (PPE) are relevant for this type of pathogen?
Lab coats, gloves, and safety goggles or a face shield (if there is splash risk) should be worn.
Which of the following is an acid produced by fermentation?
Lactic acid and propionic acid
Which of the following conditions would allow for the active transcription of the lac operon?
Lactose present, glucose absent
There are a variety of ways that microbes evade host immune defense mechanisms. A mechanism called ____________ occurs when an invading virus stops replicating until the immune response stops. NOTE: Video clarification: Herpes Zoster is another name for Shingles, but it is caused by the varicellazoster virus. [Choices: dormancy; inexpression; inactivity; latency]
Latency
Eradication of an infectious disease means that there are no longer any cases of it anywhere in the world. Which of the following types of infectious diseases would be the most difficult to eradicate?
Latent infectious diseases
Which type of method is used to determine if a prior exposure to a virus occurred?
Latex agglutination test
Which part of LPS acts as an endotoxin?
Lipid A
Endotoxins are also known as
Lipid A.
You would like to calculate the generation time of an unknown organism and set up a culture. During which of four distinct growth phases would it be best to collect data?
Log phase
The bactericidal antibiotic penicillin kills bacterial cells by preventing peptidoglycan (cell wall) biosynthesis. Which of the following phases of the bacterial growth curve would you expect penicillin to be most active against?
Logarithmic phase
The experiments that finally disproved spontaneous generation were performed by
Louis Pasteur
The experiments that finally disproved spontaneous generation were performed by:
Louis Pasteur
________ showed that biogenesis is responsible for the propagation of life.
Louis Pasteur
This image shows the results of three different bacterial species streaked onto MSA and allowed to grow overnight at 37ºC. What do the observed results of Micrococcus luteus indicate?
M. luteus is not a halophile or facultative halophile
This image shows the results of three different bacterial species that were streaked onto MSA and allowed to grow overnight at 37ºC. What do the observed results of Micrococcus luteus indicate?
M. luteus is not a halophile or facultative halophile
Part complete The typical composition of MSA is as follows: 5.0 g/L enzymatic digest of casein 5.0 g/L enzymatic digest of animal tissue 1.0 g/L beef extract 10.0 g/L D-mannitol 75.0 g/L sodium chloride 0.025 g/L phenol red 15.0 g/L agar pH 7.4 ± 0.2 at 25°C Whcih of the following statements about the media composition is FALSE?
MSA is a chemically defined media
Urinary tract infections are commonly caused by Staphylococcus saprophyticus and Escherichia coli, less commonly caused by Proteus mirabilis. You have a mixed culture of these pathogens, which you inoculate onto both MacConkey agar and nutrient agar, and then you incubate the plates at optimal growth conditions. On the MacConkey agar, E. coli appears pink, P. mirabilis appears colorless, and S. saprophyticus does not grow. All three microorganisms appear cream on the nutrient agar plate. What is the best explanation for this data?
MacConkey is both a differential and a selective medium.
Which of the following is not a way that pathogens can avoid destruction by the phagocytes of the host immune system?
Make a capsule which is toxic to the phagocyte
_____________ is a type of sexual reproduction that occurs in eukaryotes and results in four genetically unique haploid daughter cells.
Meiosis
Which of the following is false regarding normal microbiota?
Members of the normal microbiota cannot cause disease.
•__________ are moderate temperature-loving organisms that optimally grow at 25-40C.
Mesophile
What does the term mesophile mean?
Mesophiles grow well at body temperature.
Helicobacter pylori is a bacterial pathogen known to cause duodenal and gastric ulcers in humans. One of the cornerstones for treatment of H. pylori is a proton pump inhibitor. Which of the following terms best describes H. pylori?
Mesophilic acidophile
Which of the following is not a characteristic of prokaryotic flagellum?
Microtubules sprout from a centriole.
If a wild-type DNA sequence reads AAA ACG CCG AGG, what type of mutation would change it to AAA ACC CCG AGG?
Missense
Once equilibrium is reached...
Molecules move, but there is no net movement in a particular direction
What are leukocidins?
Molecules that are capable of destroying phagocytes
Which of the following is an example of a reemerging disease?
Mumps, once nearly eliminated, has increased in prevalence due to under-vaccination in industrialized countries.
Escherichia coli living in the human large intestine is known to produce vitamin K and B-complex vitamins in exchange for a nutrient-rich habitat. This host-microbe interaction is an example of __________.
Mutualism
Which of the following is a description of a symbiotic relationship in which the symbiont is helpful to the host?
Mutualism
Identifying acid-fast bacteria is important in diagnosing the presence of _________species, which include species that cause diseases such as leprosy and tuberculosis.
Mycobacterium
Which of the following infectious agents is a reemerging pathogen?
Mycobacterium tuberculosis
How do electrons get from glycolysis, the intermediate step, and the Krebs cycle to the electron transport chain?
NADH and FADH2 transport electrons to the electron transport chain.
Meningitis and gonorrhea are caused by
Neisseria species.
Which of the following is a characteristic of roundworms?
Non-segmented, elongated, cylindrical.
The most common drugs that block replication are ________.
Nuceloside analogs
Prokaryotic cells house a single circular chromosome in their __________.
Nucleoid region
Genes that are essential for survival of a bacterial cell would most likely be located _______.
On the chromosome(s)
Compared to a solution with a pH value of 4, a solution with a pH value of 2 has ________ H+ ions.
One hundred times as many
MacConkey Agar
Only gram negative bacteria will grow on the media, so all three species inoculated are gram negative Only lactose fermenting bacteria will appear as dark pinkish-purplish colored growth on the plate while non-lactose fermenting bacteria will appear colorless. Pink growth with pink media color change is usually indicative of E. coli
EMB agar
Only gram negative bacteria will grow on the media, so all three species inoculated are gram negative Only lactose fermenting bacteria will appear as purplish black to metallic green-colored growth on the plate while non-lactose fermenting bacteria will appear colorless/color of the media. Metallic green-colored growth is usually indicative of Escherichia coli
MSA agar
Only halophilic bacteria will grow on the media, so samples A, B, C are halophiles, but D isn't a halophile Mannitol-fermenting bacteria will turn the media yellow, while non-fermenters will not change the media color, so A and C are mannitol fermenters, but B isn't. An example of a halophilic, mannitol fermenter is Staphylococcus aureus. (growth plus yellow color change) An example of a halophilic non-mannitol fermenter is Staphylococcus epidermidis. (growth, no color change)
Candida albicans is part of our normal oral flora. Under certain conditions, it can overgrow, leading to oral thrush. Typically, infections are seen in individuals who are immunocompromised, such as newborns or individuals who may have recently taken antibacterial medications. This type of pathogen is classified as which of the following?
Opportunistic, endogenous pathogen
How can Organism "A" grow if it cannot ferment the carbohydrate contained in EMB media?
Organism "A" is metabolizing other nutrients contained in EMB, which do not cause acidic by-products
Which of the following statements would be most correct about the organisms growing in tubes A and B containing phenol red glucose broth?
Organism A fermented glucose, producing acid and gas, while organism B did not ferment glucose.
What do the results of organism A depicted in the image indicate?
Organism A is gram-negative, but doesn't ferment lactose
Microbes transferred via the __________ portal of exit(s) would be present in pus or drainage that is easily transmitted to others.
Otic and skin
What type of phosphorylation is used to produce ATP in the ETS?
Oxidative phosphorylation
Which type of phosphorylation mechanism is used to generate ATP in the ETS?
Oxidative phosphorylation
You are working on characterizing the metabolism on an unknown organism. You find that the organism is a strictly fermentative organism. Which of the following mechanisms is likely absent?
Oxidative phosphorylation
Which step of aerobic respiration produces the majority of ATP?
Oxidative phosphorylation- ETS
What is the final electron acceptor in aerobic cellular respiration?
Oxygen
The 1918 influenza virus killed more individuals worldwide than World War One. It is estimated that between twenty and forty percent of the world's population across continents had become infected with the virus, leading to 50 million deaths. The 1918 influenza would best be described as which of the following?
Pandemic
Which route of entry occurs when microbes enter the body through bites, cuts, injections, or surgical incision?
Parental route
A new type of fungal meningitis (infection of the nervous system) was discovered. Disease occurred among patients who had received steroid injections into their spine. What was the portal of entry?
Parenteral
IV drug users can transmit HIV and Hepatitis C by sharing needles. What is the portal of exit route?
Parenteral
_________ is the ability of an infectious agent to cause disease.
Pathogenicity
Which type of bond links amino acids together to form a protein's primary structure?
Peptide bonds
What is the key difference between photoheterotrophs and photoautotrophs?
Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source.
In an environment with sunlight and an abundance of inorganic compounds, which group of organisms are most likely to thrive?
Photolithoautotrophs
Choose the true statement about phototrophs.
Phototrophs use light for energy.
Which of the following body sites would least likely contain a biofilm?
Placenta
Which of the following eukaryotic kingdoms does not contain organisms that are pathogenic to humans?
Plantae
Which of the following groups of organisms does not have pathogenic members?
Plants
Prokaryotic and eukaryotic extrachromosomal DNA is called ______ DNA.
Plasmid
Antigenic drift occurs in microbes mainly due to _________ mutations that result in antigenic differences. These differences require the host immune system to generate a new immune response to the microbe. [Choices: point; sense; nonsense; frameshift]
Point
Antigenic drift occurs in microbes mainly due to _________ mutations that result in antigenic differences. These differences require the host immune system to generate a new immune response to the microbe.
Point
You are comparing the size of different viruses. You are specifically interested in the size of the following viruses: Ebola virus, Poliovirus, Rhinivirus, and Pithovirus. Which of these viruses would be the smallest, and which the largest?
Poliovirus is the smallest; Pithovirus the largest
How can health care workers reduce the occurrence of nosocomial infections?
Practice more stringent aseptic techniques
Which of the following infectious agents are the most difficult to control with standard autoclaving methods?
Prions
Question 17: Which of the following is not an industrial use for microbes?
Production of metal alloys
Choose the single true statement about equilibrium.
Products and reactants form at an equal rate.
Which of the following is the single most important procedure for a healthcare worker to prevent hospital-acquired infections (HAI)?
Proper handwashing
The eukaryotic cytoskeleton performs all of the following except:
Protects the cell from stress.
__________ is not an official taxonomic rank, rather it is a convenient term for describing animal-like protists that are unicellular, lack a cell wall, exhibit asexual and sexual reproduction, and live by heterotrophic means.
Protozoan
Which of the following types of organisms is associated with foodborne illness?
Psychotrophs
Which of the following microbial temperature classifications is improperly matched with its potential growth environment?
Psychrotroph - arctic lake sediment
Which of the following types of organisms uses hydrogen sulfide for reducing power?
Purple sulfur bacteria
What carbon molecules remain at the end of glycolysis?
Pyruvic acid
Which of the following would be considered a zoonotic disease?
Rabies
The binding of a ligand to a receptor, which induces the formation of a clathrin-coated pit, is the first step of _________.
Receptor-mediated endocytosis
Which of the following is not part of the five general steps that a microbe must follow in order to successfully establish an infection?
Release endotoxins
Which of the following is TRUE about retrotransposons? a. Retrotransposons never remain in their original location. b. Retrotransposons do not require an RNA intermediate. c. Retrotransposons can use a "cut-and-paste" strategy. d. Retrotransposons rely on an RNA intermediate to insert into a new part of the genome. e. Retrotransposons can use a "copy-and-paste" strategy.
Retrotransposons rely on an RNA intermediate to insert into a new part of the genome
Which of the following statements about reverse transcription is FALSE? a. Reverse transcription uses special enzymes called reverse transcriptase b. Reverse transcription is performed by certain viruses and human cells c. Reverse transcription uses RNA as a template d. Reverse transcription builds copy DNA (cDNA) e. Reverse transcription requires a particular initiation sequence
Reverse transcription requires a particular initiation sequence
How are ribozymes different from enzymes?
Ribozymes are made of ribonucleic acid, whereas enzymes are made of protein.
Which of the following statements about ribozymes is false?
Ribozymes have only been shown to act on other DNA molecules.
Which of the following is not a characteristic of the eukaryotic flagellum?
Rotary motion
Which organelle is associated with protein modification?
Rough Endoplasmic Reticulum
Which grouping of parasitic helminths includes hookworms?
Roundworms
What is the etiologic agent of typhoid?
Salmonella
Which type of microscopy uses a beam of electrons to show the surface features of a specimen?
Scanning electron microscopy (SEM)
Which of the following is a genus of fluke?
Schistosoma (blood fluke)
Which type of media has ingredients that foster the growth of certain bacteria while suppressing the growth of others?
Selective
Which of the following describes hyphae with divisions between each cell?
Septate
Siderophores such as enterobactin promote virulence through which mechanism?
Sequesters iron from the host
__________ are complexes that remove iron from transferrin for their own use.
Siderophores
Which of the following characteristics of a catheter should be considered, to help minimize the spread of nosocomial infections?
Single-use
Which portal of exit uses pus to transmit pathogens?
Skin
Be prepared to state what occurs during each phase of bacterial growth on upcoming exams.
Slide 9 powerpoint 5
The kingdom Protista is sometimes referred to as the "catchall kingdom." All of the following describe characteristics of organisms in the kingdom of Protista except:
Some only utilize RNA.
Which of the following is an asexual fungal spore?
Sporangiospores
Gamogony is the sexual phase of reproduction of ________.
Spore-forming protozoans
A catalase test would be helpful to distinguish which of the following organisms?
Staphylococcus and Streptococcus species
Which organism is most likely to be responsible for the boils?
Staphylococcus aureus
Which of the following virulence factors would be found in Staphylococcus aureus?
Staphylokinase
Which of the following would not be a component of an operon?
Start codon
Refer to the numbered steps in the figure when answering the question. Two carbons in the form of acetyl-CoA enter the Krebs cycle by joining with oxaloacetic acid, a 4-carbon molecule. During which step does carbon leave the Krebs cycle in the form of CO2?
Steps 3 and 4
Two carbons in the form of acetyl-CoA enter the Krebs cycle by joining with oxaloacetic acid, a 4-carbon molecule. During which step does carbon leave the Krebs cycle in the form of CO2?
Steps 3 and 4
Which of the following is not a part of aseptic technique?
Sterilizing surfaces in an operating room
Which of the following bacteria has an affinity for the heart valves?
Streptococcus mutans
Which of the following microorganisms use M protein to avoid destruction of a phagocyte?
Streptococcus pyogenes
Which nutrient is responsible for the development of cavities in teeth?
Sucrose
How does the antibiotic sulfanilamide inhibit bacterial growth?
Sulfanilamide is a competitive inhibitor that competes with para-aminobenzoic acid, thus affecting folic acid synthesis of a bacterial cell.
Based on the information presented in slide 11, state the nutrient requirements for an organism classified as a photoautotroph
Sun and CO2
A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n)
Superantigen
How are superantigens different from other types of exotoxins?
Superantigens cause an overstimulation of the host immune system.
________________ cause(s) a massive immune response that can destroy immune cells by overstimulation. [Choices: membrane toxicity; superantigens; cell signaling; apoptosis]
Superatigens
A patient's preliminary diagnosis, as well as the stage and site of infection, affect how and when a representative sample is obtained for microbiological analysis. Which would be the most appropriate tools to collect samples from a patient infected with Clamydia trachomatis?
Swab with a plastic or wire shaft and a non-cotton tip
Which of the following does not belong to the kingdom Protista?
Tapeworms
How does a capsule help certain bacteria evade detection by the immune system?
The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.
Which of the following statements correctly describes what happens during chemiosmosis?
The energy of protons flowing through the ATP synthase enzyme powers the recharge of ADP to ATP.
The generation time for Escherichia coli inside of the human intestinal tract has been estimated at 12 hours. However, when grown in Luria Bertani medium as a pure culture under standard laboratory conditions, the generation time for E. coli is 20 minutes. Which of the following accounts for this discrepancy in generation time?
The human intestinal tract contains other microbes, which compete for limited nutrients.
Which of the following is an example of a measure of association?
The infant mortality rate in the United States due to consumption of unpasteurized honey
Which of the following correctly describes Infectious Dose-50 (ID50)?
The more infectious the pathogen is, the lower the ID50.
Which of the following descriptions provides the best definition for mortality rate?
The number of deaths during a specific time period
Isotopes are atoms of the same element that differ in
The number of neutrons found in the nucleus
Assume you know a cell is acid fast. Which of the following can you most safely conclude?
The organism is Gram-positive.
An individual with type I diabetes hasn't been able to afford insulin since he lost his job over a week ago. He goes to the clinic complaining of nausea and breathing difficulty. Blood work revealed that the patient was in a state of ketoacidosis and had high blood glucose levels. However, ketoacidosis results when the body is "starving" for glucose. Why can these two conditions simultaneously exist in a diabetic patient?
The patient was not taking insulin, which means that the glucose in the bloodstream couldn't get into the patient's cells to be catabolized.
A potential antimicrobial drug is tested and found to strip away the capsules made by certain pathogenic bacteria. How would this drug affect the bacteria's ability to cause disease?
The phagocytes would be better able to ingest the bacteria.
Which is an example of vehicle disease transmission?
The presence of Listeria on undercooked chicken served for dinner
Which of the following is a trait unique to photosynthetic eukaryotes?
The presence of chloroplasts
The rough ER and the smooth ER are distinguished from each other by
The presence or absence of membrane-bound ribosomes
Which of the following is false regarding the sickle cell trait?
The sickle cell trait is caused by malarial parasite infections
Nucleolus is...
The site where ribosomes are built
An atom is best described as
The smallest unit of an element
Chloroflexus aurantiacus is a photoautotrophic bacterium that grows in hot springs. Which of the following serves as an energy source for C. aurantiacus?
The sun
You inoculated a pure culture of unknown bacteria into a tube containing thioglycollate medium to study their metabolic relationship with oxygen. The culture was incubated for an appropriate length of time at the optimal growth temperature of the organism. When you examined the culture, you observed that although the organism grew throughout the medium, the growth was denser at the surface. What would you conclude about the oxygen requirements for this unknown species?
The unknown is a facultative anaerobe.
How is Streptococcus pneumoniae able to avoid destruction by a phagocyte?
Their capsules make them "slippery" to phagocytes.
What is the definition of eradication of an infectious disease?
There are no longer any cases of the microbe anywhere in the world for three consecutive years.
Why are invasive procedures likely to increase the risk of nosocomial infections?
These procedures allow microbes from the skin to enter the bloodstream of the patient.
Listeria monocytogenes is an intracellular bacterial pathogen that replicates within macrophages. Secretion of listeriolysin O and phospholipase helps the pathogen to escape phagolysosome formation following internalization by the host cell. In this example, listeriolysin O and phospholipase A perform which essential function?
These virulence factors help the pathogen evade host defenses.
Why are Koch's postulates important to microbiology?
They allowed us to identify the causative pathogens of many infectious diseases.
Which statement is true about standard precautions?
They apply to all healthcare providers working with all patients.
How are immune cells able to detect foreign pathogens?
They are able to detect structures on the surfaces of foreign cells that are not found in the host.
Which of the following is not a characteristic of archaeal plasma membranes?
They are made of linear fatty acids
Which of the following is not a characteristic of archaeal plasma membranes?
They are made of linear fatty acids.
Which of the following is true about inorganic cofactors?
They are nonprotein agents.
Why are biochemical tests referred to as "fingerprint methods of bacterial species"?
They are used to identify bacterial species.
How do fibrinolysins enhance a pathogen's virulence?
They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.
How do Shigella cells move between host cells?
They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another.
How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system?
They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.
Which of the following is not a reason that acid-fast bacteria are clinically a challenge?
They form endospores that resist heat and sanitizing practices
Select the false statement about Mycoplasma?
They have a cell wall.
If a patient notices a healthcare worker not following suggested precautions,
They should immediately bring it to the attention of the healthcare worker.
How can surgeons help to limit nosocomial infections?
They should perform surgeries and invasive procedures only when absolutely necessary.
A virulence study was performed using Staphylococcus aureus in mice. It was determined that the LD50 for the S. aureus alpha-toxin was 0.045 µg/kg of body weight toxin (a relatively low LD50). In the same mouse population, the ID50 was determined to be 200,000 cells (a relatively high ID50). What do these results taken together mean?
This S. aureus strain is less infectious, but its alpha-toxin is highly-toxic.
What is the role of light energy in photosynthesis?
To produce a proton gradient to make ATP
When toxins enter the host's bloodstream, the resulting condition is called ____________.
Toxemia
Which of the following is not a mycosis?
Toxoplasmosis.
How does transformation differ from conjugation?
Transformation takes up DNA from the environment
Transposons, also known as "jumping genes," can have a wide-range effect on cells. Which of the following would NOT likely be an effect?
Transposons can repair damaged DNA
The preference of a pathogen for a specific host is also known as ___________.
Tropism
T/F: Bright field microscopy is the simplest and most common form of microscopy.
True
T/F: Eukaryotic cells evolved from prokaryotic cells.
True
T/F: Fluorescence microscopy is when fluorochromes stain a sample so it will fluoresce when exposed to UV light.
True
T/F: Fluorochromes can be natural or synthetic.
True
T/F: Prokaryotes are unicellular and lack a membrane-bound nucleus.
True
T/F: The Eukaryotic cytoskeleton arises from the centrosome
True
T/F: The first amino acid in a eukaryotic protein sequence is methionine, whereas the first amino acid in a prokaryotic protein sequence is formyl methionine.
True
T/F: The genetic code is redundant, with multiple codons specifying a single amino acid.
True
T/F: The nucleus has a membrane that gives rise to the endoplasmic reticulum.
True
T/F: Transmission electron microscopy provides information about internal structures.
True
__________ pathogens are always capable of causing disease in a host, regardless of their health status.
True
Which of the following microorganisms actually grows inside the macrophage?
Tuberculosis bacterium
Superantigens belong to which family of exotoxins?
Type 1
You attended a BBQ and ate a variety of foods, including pototato and egg salads. After you arrive home a few hours later, you display symptoms of food poisoning (vomiting, diarrhea, cold sweats, etc). Which type of exotoxin did you likely ingest?
Type I
Which of the following types of toxins damage cells by binding to host cell receptors?
Type I exotoxins
AB toxins belong to which family of exotoxins?
Type III
Exotoxins are often classified into three main families based on their mode of action. Which of the following pairs is correctly matched?
Type III - intracellular toxin
Bacillus anthracis is a Gram-positive bacterial pathogen known to cause anthrax. B. anthracis secretes a three-protein toxin: protective antigen, lethal factor, and edema factor. Protective antigen binds the host cell surface at cell receptor TEM8. Following proteolytic cleavage, protective antigen forms a membrane channel that allows the passage of lethal factor and edema factor into the cytoplasm. Once inside, edema factor acts as an adenylate cyclase, while lethal factor acts as a zinc metalloprotease, both leading to reduced host cell signaling. Anthrax toxin is best described as a(n) ___________.
Type III exotoxin
Where are cilia found in the human body?
Upper respiratory tract
Which of the following nitrogen bases is found only in RNA and NOT in DNA?
Uracil
What is the portal of entry of the pathogen that causes gonorrhea?
Urogenital
Which of the following is a characteristic of amoeboid protozoans?
Utilize pseudopods for movement.
__________ contain mainly water and other substances and are mainly found in plants, fungi, and certain prokaryotes and protists.
Vacuoles
___________ are usually found in an atom's outermost shell and tend to participate in chemical reactions.
Valence electrons
There are a variety of ways that microbes evade host immune defense mechanisms. Antigenic ___________ occurs when the pathogen changes surface antigens to remain undetected by the host immune system. [Choices: alteration; switching; modification; variation]
Variation
There are a variety of ways that microbes evade host immune defense mechanisms. Antigenic ___________ occurs when the pathogen changes surface antigens to remain undetected by the host immune system.
Variation
HIV-positive mothers can transmit the virus through breastfeeding. This is considered __________ transmission.
Vertical
The degree or extent of disease that a pathogen causes is
Virulence
Certain traits that allow pathogens to create infection and cause disease are termed
Virulence factors
A previously undescribed infection has been detected among inhabitants in an isolated village in a remote tropical rainforest. When serum from an infected individual is passed through a filter, the infection can be transmitted to laboratory animals. Nothing is observed when the serum is examined with a light microscope at the highest magnification. Biochemical tests show the presence of RNA and protein but no carbohydrates or lipids. This data is consistent with what type of infectious agent?
Virus
Which of the following would be the best general description of a "virus?"
Viruses are acellular infectious agents
Which type of lipid is incorrectly matched to its description? a. Wax: Refers to any lipid which is solid at room temperature b. Phospholipid: An amphipathic lipid found in the plasma membrane of cells c. Steroid: Made of four fused hydrocarbon rings d. Glycolipid: A lipid linked to a carbohydrate Mono-, di-, or triglyceride: One, two, or three fatty acids linked to a glycerol molecule
Wax: Refers to any lipid which is solid at room temperature
Your patient is suffering from severe diarrhea caused by a Clostridium difficile infection. Which of the following would be a special type of contact precaution to prevent spread of the organisms?
Wear a barrier gown at all times.
Which of the following best describes a prophage?
When a phage genome is integrated into the host cell's chromosome
You believe that you have performed a perfect Gram stain on a mixed culture of Gram-positive and Gram-negative bacteria, yet when you observe the cells under the microscope, they all appear pink. What went wrong?
You left the decolorizer on the smear for too long
What observations could you make in the case of a positive catalase test?
You may see bubbles develop upon adding hydrogen peroxide to the sample.
You have isolated a suspected pathogen in pure culture from a diseased laboratory animal. You are not sure whether that organism is what is causing the disease. Applying Koch's postulates, what would be the next step to find out more about the organism?
You should introduce it back into a healthy animal model, and the organism should display the same symptoms.
You are testing a chemical that you suspect is a mutagen. You set up an AMES test, and for your control (without the mutagen added to the bacterial culture) you observed only a few colonies. After you added the mutagen to the test sample, you observed similar results to your control—only a few colonies grew. What can you conclude about the chemical?
Your chemical is not mutagenic
Tropism is best described as:
a pathogen's preference for a specific host.
In an inducible operon, what protein is used to turn off transcription by binding to the operator sequence?
a repressor protein
Which of the following best describes the tertiary structure of proteins? a. 3D globular structures stabilized by covalent disulfide bridges b. Amino acids linked by peptide bonds c. Linear protein folded into alpha helices and beta- pleated sheets d. Two or more polypeptide chains interacting to form a higher-order structure
a. 3D globular structures stabilized by covalent disulfide bridges
Select the true statement(s) about bright field microscopy. To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. a. A dark image is contrasted on a bright background. b. It illuminates the specimen using visible light. c. Living microorganisms are viewed by bright field microscopy. d. Bright field microscopy is the most simple and common form of microscopy.
a. A dark image is contrasted on a bright background. b. It illuminates the specimen using visible light. d. Bright field microscopy is the most simple and common form of microscopy.
Nonspecific permeases a. Allow a variety of molecules to cross the cytoplasmic membrane. b. Are not used for passive transport. c. Allow only water to cross the cytoplasmic membrane. d. Allow only one type of solute to pass through the membrane.
a. Allow a variety of molecules to cross the cytoplasmic membrane.
Choose the false statement about aseptic culturing techniques. a. Aseptic technique is unnecessary in most labs because the majority of microbes are not pathogenic. b. Aseptic culture techniques require that sterile media are used to grow microbes. c. Aseptic culture techniques require that any instrument that contacts a culture must be sterile. d. Aseptic technique includes hand-washing.
a. Aseptic technique is unnecessary in most labs because the majority of microbes are not pathogenic.
Which statement is not true about the virus capsid? a. Because the capsid is not essential to the virus, it is not a useful target for antiviral drugs. b. The capsid functions as a package for the viral genetic material. c. The capsid determines the shape of the virus. d. The capsid is made of one or more types of protein subunits. e. Both bacteriophage and animal viruses have capsids.
a. Because the capsid is not essential to the virus, it is not a useful target for antiviral drugs.
Which statement is not true about eukaryotic ribosomes? a. Bound ribosomes are always bound while free ribosomes are always free. b. Both bound and free ribosomes consist of a 40S and a 60S subunit. c. Bound ribosomes are attached to the endoplasmic reticulum (ER). d. Ribosomes found in mitochondria are 70S rather than the 80S type found in the cytoplasm. e. Bound ribosomes produce proteins that are destined for secretion from the cell.
a. Bound ribosomes are always bound while free ribosomes are always free.
Which type of cellular transport uses transport proteins and moves substances from an area of high concentration to an area of low concentration? a. Facilitated diffusion b. Phosphotransferase system c. Secondary active transport d. Simple diffusion e. Primary active transport
a. Facilitated diffusion
Which does not describe eukaryotic flagella? a. Flagellin protein b. 9+2 arrangement of microtubules c. Anchored by a basal body connected to a centriole d. Whip-like motion e. Plasma membrane-enclosed
a. Flagellin protein
__________ are a collection of tubular structures, either septate or aseptate, which allow for growth in most fungi. a. Hyphae b. Conidiospores c. Mycoses d. Spores
a. Hyphae
Which of the following is an example of phage conversion? a. Infection of Streptococcus pyogenes with T12 phage enables the bacteria to produce erythrogenic toxins, allowing it to cause scarlet fever. b. Lambda phages can use either the lytic cycle or lysogenic pathway for replication. c. Despite a single infection, ultimately multiple host cells will carry the bacteriophage genome during the lysogenic replication cycle. d. Following injection of viral nucleic acid into a host cell, the genetic material is incorporated into the host genome.
a. Infection of Streptococcus pyogenes with T12 phage enables the bacteria to produce erythrogenic toxins, allowing it to cause scarlet fever.
Which of the following statements about the lagging strand is FALSE? a. It uses only one molecule of DNA polymerase I b. It synthesizes many RNA primers c. It is a discontinuous process d. It builds in the opposite direction of the helix unwinding e. It is where one would find Okazaki fragments.
a. It uses only one molecule of DNA polymerase I
Protozoans are mainly grouped by their __________. a. Means of motility b. Spore-forming potential c. Nutritional requirements d. Mode of reproduction
a. Means of motility
Mitochondria do not participate in which function? a. Motility b. Programmed cell death c. Production of ATP d. Production of amino acids and vitamins e. Regulation of cell division
a. Motility
Van der Waals interactions a. Occur when temporary dipoles within molecules form that are not the result of hydrogen bond to O, N, or F atoms. b. Exhibit a force of repulsion that serves to destabilize molecules. c. Are responsible for the repulsion between hydrophilic and hydrophobic compounds. d. Are stronger than either hydrogen bonds or ionic bonds. e. Are another name for hydrogen bonds.
a. Occur when temporary dipoles within molecules form that are not the result of hydrogen bond to O, N, or F atoms.
An individual uses an in-home test kit one week after engaging in high-risk behavior for HIV infection. The test kit uses a saliva sample that is mailed to a lab where an agglutination test to detected HIV antibodies is run. The results come back negative for HIV. What should the patient consider regarding these test results? a. One week may not be enough time for HIV antibodies to be detected b. An ELISA test is needed to detect the presence of HIV nucleic acid c. Agglutination tests will not detect viruses if the infection is latent d. Agglutination tests will not detect viruses if the infection is latent, nor are they appropriate for testing samples of body fluids e. Agglutination tests are not appropriate for testing samples of body fluids
a. One week may not be enough time for HIV antibodies to be detected
You observe that when you grow Serratia marcescens at human body temperature, the resulting bacterial colonies appear white. However, when you grow the same bacterium at room temperature, the colonies that grow are red. This difference in pigmentation is best described as a ____________. a. Phenotype difference b. Genome difference c. Gene difference d. Genotype difference
a. Phenotype difference
Choose the features of the prokaryotic ribosome that support the endosymbiotic theory. a. Prokaryotes have a ribosome with a 70S sedimentation rate. b. Prokaryotes have a ribosome with a 80S sedimentation rate. c. Prokaryotic ribosomes build proteins by linking amino acids together. d. Prokaryotic ribosomes have a lower overall mass and diameter compared to eukaryotic ribosomes.
a. Prokaryotes have a ribosome with a 70S sedimentation rate.
Which of the following is TRUE about ribosomes? a. Prokaryotic ribosomes have a lower overall mass and diameter than eukaryotic ribosomes. b. Antibiotics often take advantage of functional differences between prokaryotic and eukaryotic ribosomes. c. Ribosomes build amino acids by linking together nucleic acids. d. Prokaryotic ribosomes are also easily differentiated from eukaryotic ribosomes based on chemical composition. e. Ribosomes are organelles made of RNA and carbohydrates.
a. Prokaryotic ribosomes have a lower overall mass and diameter than eukaryotic ribosomes.
Choose the FALSE statement(s) about acids and bases. To be marked correct, you'll need to select all false statements, as there may be more than one correct answer. a. Pure water has more H+ ions than OH- ions. b. Bases release OH- ions in an aqueous solution. c. Acids contribute H+ ions to an aqueous solution. d. If an acid is added to an acidic solution, the pH will increase.
a. Pure water has more H+ ions than OH- ions. d. If an acid is added to an acidic solution, the pH will increase.
Choose the correct statement about viral evolution. a. RNA viruses mutate faster than DNA viruses due to a lack of proofreading replicative enzymes. b. RNA and DNA viral genomes evolve at equal rates. c. Cellular genomes mutate at a faster rate than viral genomes due to their large size and increased chance of replicative mistakes. e. DNA viruses mutate faster than RNA viruses because thymine is more susceptible to mutation than uracil.
a. RNA viruses mutate faster than DNA viruses due to a lack of proofreading replicative enzymes.
Oncogenic viruses a. Stimulate uncontrolled host cell division b. Suppress the host immune system c. Increase host cell responsiveness to death signals d. Are never RNA viruses e. Always integrate into the host cell DNA.
a. Stimulate uncontrolled host cell division
All of the following can make interpreting the Gram stain difficult except a. The culture is between 24 and 48 hours old. b. Testing bacteria that are forming endospores. c. The culture is more than 48 hours old and contains damaged cells. d. Testing bacteria with especially resistant cell walls. e. Testing bacteria that have a waxy cell wall.
a. The culture is between 24 and 48 hours old.
Viruses are considered to be non-living pathogens for which reason? a. Their lack of metabolic processes b. Their unique type of cells and their lack of metabolic processes c. Their extremely small size d. Their unique type of cells e. Their ability to synthesize only some of their own components
a. Their lack of metabolic processes
If a bacterial cell with a damaged cell wall is placed in a hypotonic solution it will ___________.
absorb water from the environment and lyse.
Which molecule is the product of the intermediate step which is a direct input into the Krebs cycle?
acetyl CoA
After translation, protein modifications are necessary for a final functioning product. Which of the following is NOT part of protein modification?
addition of a methionine
A pure culture of bacteria isolated from a nasal swab is inoculated on a sheep's blood agar plate. After an overnight incubation to promote bacterial growth, a greenish discoloration of the media is observed where the bacteria have grown. What type of blood hemolysis pattern does this result indicate?
alpha
A pathway that functions simultaneously in both anabolism and catabolism is termed
amphibolic.
An essential amino acid is __________.
an amino acid the cell cannot make and must obtain from the environment
Clostridium difficile causes severe diarrhea. Many times proliferation of this microbe in the gut is associated with the overuse of _____________.
antibiotics
Upon entering the host, the pathogen may conceal antigenic features so the immune system doesn't quickly mount an attack. This is also known as
antigen masking
Yearly vaccinations for influenza are necessary due to __________.
antigenic drift
Properties that contribute to virulence
are determined by both the microbe and the host, and may evolve over time.
Endemic infections
are routinely detected in a population or region.
When practicing aseptic culturing techniques, it is important to keep all of the following in mind except a. The media used to grow the specimen is sterile. b. As long as nothing unintended touches the media, there will be no contamination. c. Gloves and other protecting clothing may be required depending on the specimen being used. d. Surrounding surfaces are decontaminated before and after handling cultures. e. All of the instruments and lab ware that directly touch the specimen is sterile.
b. As long as nothing unintended touches the media, there will be no contamination.
Which of the following is not a mechanism for horizontal gene transfer? a. Conjugation b. Binary fission c. Transduction d. Transformation
b. Binary fission
Which of the following is (are) ORGANIC? To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. a. CO2 b. CH4 c. C6H12O6 d. HCl
b. CH4 c. C6H12O6
Which of the following does NOT represent a shape or arrangement that a prokaryote can assume? a. Stella are star shaped cells. b. Clusters of bacilli form a Staph arrangement. c. Clusters of bacilli form a Pallisade arrangement. d. Vibrio are comma shaped cells.
b. Clusters of bacilli form a Staph arrangement.
Prokaryotic and eukaryotic ribosomes share which of the following features? a. Contain a large and a small subunit b. Composed of a large and a small subunit and composed of protein and rRNA c. Function is making DNA d. Composed of protein and rRNA e. Composed of protein and rRNA, composed of a large and a small subunit, and function is making DNA
b. Composed of a large and a small subunit and composed of protein and rRNA
Which of the following is an unsuitable culture method for an animal virus? a. Tissue culture method b. Direct inoculation of virus onto blood agar c. Live animal inoculation d. Injection of virus into embryonated eggs
b. Direct inoculation of virus onto blood agar
An elderly patient who contracted chickenpox as a child now has shingles as an adult. You explain to your patient that both diseases are caused by the same virus, which lays dormant in the body prior to reactivation. Based on this information, choose the TRUE statement. a. Infected host cells will carry a provirus until sufficient viral load has been reached. b. During dormant periods, the virus exists episomally inside of infected host cells. c. Viral replication occurs as a steady, logarithmic increase over time. d. Your patient's infection is best characterized as an acute, non-persistent infection.
b. During dormant periods, the virus exists episomally inside of infected host cells.
Which of the following is true about endospores? a. Endospores are only viable for a short time. b. Endospores are highly resistant to environmental stress. c. Endospores are metabolically active structures. d. Endospores are considered reproductive structures. e. Endospores are susceptible to various chemicals.
b. Endospores are highly resistant to environmental stress.
Short, bristle-like structures that extrude from the surface of a prokaryotic cell are called a. Cilia b. Fimbriae c. Pili d. Flagella e. Mating bridges
b. Fimbriae
_____________ bacteria lack an outer membrane, have a thick layer of peptidoglycan, contain teichoic acid, and lack mycolic acid. a. Gram-negative b. Gram-positive c. Gram-variable d. Acid-fast
b. Gram-positive
HIV, the virus which causes AIDS, interacts with two receptors on the host cell membrane: CD4 and CCR5. A small percentage of individuals have a genetic mutation which causes their cells to lack CCR5. These individuals will never develop AIDS nor are they able to pass HIV on to others. Which part of viral replication is being blocked by the lack of a receptor? a. The host cell enzymes are unable to replicate the HIV genome. b. HIV cannot attach to the host cell without the proper membrane receptor. c. Endocytosis is being prevented. d. The virus components cannot be assembled into new virions. e. Newly assembled virions cannot be released from the host cell.
b. HIV cannot attach to the host cell without the proper membrane receptor.
Which of the following is not needed to carry out excision repair in Escherichia coli? a. Excision complex b. Helicase c. DNA ligase d. DNA polymerase I
b. Helicase
The goal of the streak plate technique is to a. Compare how the shape, color and margin differ in colonies from a pure culture. b. Isolate a pure culture for study from a single colony. c. Visualize all of the colonies on a plate from a pure culture. d. Spread out a thick layer of bacteria and isolate the bacteria that outcompete the rest. e. Compare all of the colonies on a plate with a mixed culture.
b. Isolate a pure culture for study from a single colony.
What does the plaque assay determine? a. If the virus can grow in a live animal host b. Number of bacteriophage in a sample c. If the phage is a lysogenic phage d. If a given drug will be useful in treating a given viral infection e. Type of bacteriophage in a sample
b. Number of bacteriophage in a sample
A nurse experienced an accidental needle stick while treating a patient who has hepatitis C. The seroconversion window for hepatitis C is approximately 6-8 weeks. Given this information, which of the following viral detection methods would be most appropriate for detecting a hepatitis C infection in the nurse one week following the needle stick? a. Plaque assay b. PCR-based detection of hepatitis C RNA c. ELISA-based detection of anti-hepatitis C antibodies d. Modified latex agglutination test for detection of anti-hepatitis C antibodies
b. PCR-based detection of hepatitis C RNA
How is simple diffusion different from other types of passive transport? a. Simple diffusion is only the diffusion of water. b. Simple diffusion does not require a permease. c. Simple diffusion requires ATP. d. Simple diffusion only brings material into the cell, not out of it.
b. Simple diffusion does not require a permease.
Which is not a cancer linked to a specific virus? a. Kaposi sarcoma b. Skin cancer c. Adult T-cell leukemia d. Liver cancer e. Cervical cancer
b. Skin cancer
Choose the TRUE statement about the Domain Bacteria. a. The Domains Bacteria and Archaea are genetically identical. b. The Domain Bacteria is made up of prokaryotes and likely originated 3.8 billion years ago. c. Bacteria inhabit extreme environments and are not linked to human diseases. d. The Domain Eukarya is more closely related to the Domain Bacteria than to the Domain Archaea.
b. The Domain Bacteria is made up of prokaryotes and likely originated 3.8 billion years ago.
What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane? a. The cell will swell up with water and burst. b. The cell will lose its interior water, causing it to shrivel up and possibly die. c. The cell will pump the salt in the cytoplasm out of the cell via simple diffusion.
b. The cell will lose its interior water, causing it to shrivel up and possibly die.
Why is no energy required in passive transport? a. The membrane physically moves the molecules. b. The concentration gradient drives the movement. c. Transport proteins move the molecules, so no energy is required.
b. The concentration gradient drives the movement.
The rabies virus primarily affects the nervous system. The specificity that the rabies virus has for neuronal host cells is primarily dictated by __________________________. a. The helical shape of its viral capsid b. The spikes that protrude from its viral envelope c. The type of nucleic acid used for its viral genome (single-stranded, antisense RNA) d. The segmented nature of its viral genome
b. The spikes that protrude from its viral envelope
Which of the following is an example of bioremediation? a. The use of microbes to make antibiotics b. The use of Marinobacter species to degrade oil c. The use of Xanthomonas campetris to make xanthum gum as a food additive d. The use of Escherichia coli to metabolize sewage to produce diesel fuel
b. The use of Marinobacter species to degrade oil
Which statement is true about valence electrons? a. Valence electrons participate in chemical reactions. b. Valence electrons participate in chemical reactions, and interactions between valence electrons in reacting atoms determine what kind of chemical bond is formed. c. Valence electrons are found in the innermost shell and participate in chemical reactions. d. Interactions between valence electrons in reacting atoms determine what kind of chemical bond is formed. e. Valence electrons are found in the innermost shell.
b. Valence electrons participate in chemical reactions, and interactions between valence electrons in reacting atoms determine what kind of chemical bond is formed.
Challenges in developing effective antiviral drugs with minimal side effects to the patient include a. Only the attachment stage of the viral life cycle is a suitable target for antiviral drug action. b. Viruses use the cell's own machinery and metabolism for replication. c. The immune system is rarely successful in ending viral infections so there is no natural model to work from. d. Drugs can be easily delivered to reach viruses within host cells. e. Viruses have many more chemically distinct targets than living pathogens.
b. Viruses use the cell's own machinery and metabolism for replication.
Which of the following is an endogenous source of infection?
bacteria from the skin entering a surgical incision
Which of the following is an example of a biofilm?
bacteria growing in plaque
Staphylococcus aureus is streaked on MSA and allowed to grow overnight at 37ºC. What results would you expect to observe on MSA?
bacterial growth with yellow colored media
The primary difference between a biological and a mechanical vector is that:
biological vectors play a role in the pathogen's life cycle, whereas a mechanical vector spreads disease without being integral to a pathogen's life cycle.
Droplet and airborne precautions
both involve diseases of the respiratory system and/or diseases transmitted through a respiratory route.
Which stage of animal virus replication may be blocked by a drug that binds with the viral spike? a. Replication b. Penetration c. Attachment d. Assembly e. Uncoating
c. Attachment
How does the cell wall of bacteria and archaea differ? a. Bacteria have a lot of diversity in the makeup of their cell walls. b. Archaea have little diversity in the makeup of their cell walls. c. Bacteria use peptidoglycan. d. Archaea use peptidoglycan. e. Bacteria use pseudopeptidoglycan.
c. Bacteria use peptidoglycan.
__________ are small proteins that help fold larger proteins. a. Polypeptides b. Amino acids c. Chaperones d. Proteases
c. Chaperones
Bacterial cells use DNA replication to: a. Manifest multiple phenotypes at once. b. Build functional proteins. c. Copy their genetic material prior to binary fission. d. Make back-up copies of their genome in case of a mutation.
c. Copy their genetic material prior to binary fission.
A similarity between mitosis and meiosis is a. Two sequential cell divisions. b. Production of daughter cells with the same number of chromosomes as the parent. c. Copying DNA before the cell divides. d. Production of genetically unique daughter cells. sexual reproduction.
c. Copying DNA before the cell divides.
Choose the FALSE statement about cellular transport mechanisms. a. Osmosis is the passive movement of water from a low-solute concentration to a high-solute concentration. b. Facilitated diffusion does not require energy and uses membrane proteins to move substances down their concentration gradient. c. Diffusion is the passive movement of substances from areas of low concentration to areas of high concentration. d. Active transport requires energy and uses carrier proteins to move substances against their concentration gradient.
c. Diffusion is the passive movement of substances from areas of low concentration to areas of high concentration.
Which of the following is not one of the four main groups of biomolecules? a. Proteins b. Carbohydrates c. Electrolytes d. Nucleic acids e. Lipids
c. Electrolytes
The _______ resembles a series of flat sacs called cisternae. This organelle modifies, builds, sorts, and distributes products to the cell membrane to be secreted. a. Rough endoplasmic reticulum b. Plasma membrane c. Golgi apparatus d. Smooth endoplasmic reticulum
c. Golgi apparatus
Which of the following is (are) mismatched? To be marked correct, you'll need to select all mismatched statements, as there may be more than one correct answer. a. Negative stain: typically does not require heat or chemical fixation of the sample prior to staining b. Bacterial endospore stain: a structural stain c. Gram stain: turns Gram-negative cells purple d. Acid-fast stain: turns acid-fast cells blue
c. Gram stain: turns Gram-negative cells purple d. Acid-fast stain: turns acid-fast cells blue
Robert Koch helped establish the germ theory of disease by discovering that anthrax was caused by a disease. After he isolated and purified the same bacteria from several diseased animals, what would be the next step in order to show that this bacteria caused anthrax? a. Culture the bacteria on Petri dishes b. Perform physiological testing c. Introduce the bacteria into a new mouse to see if it established the same infection d. Visualize the bacteria with an electron microscope e. Find out if antibiotics treat the diseased animals
c. Introduce the bacteria into a new mouse to see if it established the same infection
Choose the FALSE statement about the eukaryotic cytoskeleton. a. It arises from the centrosome. b. It assists with maintaining the cell's shape. c. It is an extension of the glycocalyx. d. It protects against external mechanical stress forces.
c. It is an extension of the glycocalyx.
The symbiotic relationship represented by the production of vitamin K in the human large intestine by Escherichia coli is best described as _________. a. Commensalism b. Parasitism c. Mutualism d. Pathogenicity
c. Mutualism
Which of the following structures allow bacteria to transfer genetic information through conjugation? a. Capsule b. Fimbriae c. Pili d. Glycocalyx e. Slime layer
c. Pili
You have isolated a new eukaryotic organism which is unicellular and performs photosynthesis. The organism is most likely classified as a(n) a. Bacterium b. Fungi-like protista c. Plant-like protista d. Fungus e. Animal
c. Plant-like protista
Choose the TRUE statement about post-translational modifications. a. Post-translational modifications are added to a limited number of distinct proteins in eukaryotes b. Post-translational modifications affect how quickly an mRNA molecule is degraded following translation c. Post-translational modifications include phosphorylation, trimming, and addition of organic factors d. Post-translational modification occurs at the ribosome.
c. Post-translational modifications include phosphorylation, trimming, and addition of organic factors
Select the false statement about the differences between eukaryotes and prokaryotes. a. Prokaryotes only include unicellular archaea and bacteria. b. Eukaryotes have a defined nucleus and other membrane bound organelles, while prokaryotes lack a nucleus. c. Prokaryotic cells can exhibit both asexual and sexual reproduction, whereas eukaryotes only carry out asexual reproduction. d. Most prokaryotes have a single circular chromosome, as compared to a eukaryote's larger genome spread across multiple linear chromosomes.
c. Prokaryotic cells can exhibit both asexual and sexual reproduction, whereas eukaryotes only carry out asexual reproduction.
Which particle is described INCORRECTLY? a. Neutron: Found in the nucleus and 1 atomic mass unit b. Electron: Negatively charged and negligible mass c. Proton: Found in shells orbiting the nucleus d. Proton: Positively charged and 1 atomic mass unit e. Electron: Found in shells orbiting the nucleus
c. Proton: Found in shells orbiting the nucleus
Which of the following is incorrectly matched? a. Acid: Release hydrogen ions (H+) in an aqueous solution b. Water: Is the solvent in aqueous solutions c. Salt: Formed by the combination of hydrogen ions (H+) and hydroxide ions (OH-) d. pH: Measure of the acidity or basicity of a solution e. Base: Release hydroxide ions (OH-) in an aqueous solution
c. Salt: Formed by the combination of hydrogen ions (H+) and hydroxide ions (OH-)
Which of the following vesicles is INCORRECTLY matched with its function? a. Lysosomes: contain hydrolytic enzymes and act as garbage disposal tools for the cell b. Peroxisomes: contain enzymes that break down fats and amino acids and protect the cell from hydrogen peroxide c. Secretory vesicles: ferry digestive enzymes to the endoplasmic reticulum d. Transport vesicles: move substances around the cell
c. Secretory vesicles: ferry digestive enzymes to the endoplasmic reticulum
Considering the process of osmosis, what will occur if a bacterial cell is put into a hypotonic solution? a. The cell will lose water and undergo plasmolysis. b. There will be no net movement of water into or out of the cell. c. The cell will take on water and may lyse if its cell wall is damaged. d. The cell will absorb salt from its environment.
c. The cell will take on water and may lyse if its cell wall is damaged.
You observe that a novel virus penetrates the host cell through membrane fusion. Which of the following statements must also be true regarding this virus and its replicative cycle? a. Replication occurs in the nucleus of the host cell b. The virus does not undergo uncoating c. The virus releases from host cells by budding d. The virus undergoes lysogenic replication
c. The virus releases from host cells by budding
Which of the following could be used as evidence for spontaneous generation? a. The broth in Pasteur's S-necked flasks did not spoil. b. Flies lay eggs that develop into maggots. c. Uncovered meat will give rise to maggots. d. Shaking Pasteur's S-necked flasks did spoil the broth. e. Gauze-covered meat will not give rise to maggots.
c. Uncovered meat will give rise to maggots.
What is an example of a virulence factor that is related to immune system evasion?
capsule
Biological macromolecules that follow the general molecular formula (CH2O)n are __________.
carbohydrates
Sophisticated proteins require __________ to help with folding into the final protein structure.
chaperones
If a patient is asymptomatic for long periods of time but has symptoms reemerge, they are in a __________ state.
chronic carrier
Patients infected with Herpes simplex virus-1, the causative agent of fever blisters, go through periods of viral inactivity (where no active oral cankers appear) and outbreaks (where fever blisters are present). This type of individual is best defined as a(n) _______________.
chronic carrier
The common cold is a good example of a __________ disease.
communicable
During optimum conditions, E. coli will replicate every 20 minutes. Because the genes required for replication are needed as part of a routine function, these genes are considered __________.
constitutive genes
When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered
contact transmission.
Enzyme specificity allows for __________.
controlled cellular processes
Respiratory pathogens cause symptoms of _________ that make it more likely that it will be transmitted to other hosts.
coughing and sneezing
Smoking causes lung cancer. The validity of this statement was first verified by ________ studies.
cross-sectional
The biochemical test shown in the image is used to identify bacteria that produce a certain enzyme of the bacterial electron transport chain that is present in aerobic bacteria. Name the enzyme and state which of the results observed in the image is a positive result.
cytochrome C oxidase/A
•Where does glycolysis occur in prokaryotic and eukaryotic cells?
cytoplasm - prokaryotes mitochondria- eukaryotes
In the Spring of 2009, a novel H1N1 virus emerged that had a new combination of genes from pigs, humans, and birds. As a result, the virus spread quickly, resulting in a swine flu pandemic. Which of the following concepts explains why the outbreak occurred? a. Attenuation b. Narrow tropism c. Antigenic drift d. Antigenic shift
d. Antigenic shift
Why can't prokaryotic species be defined as a group of similar organisms that could sexually reproduce together? a. They can be. b. We can't see them in enough detail to tell how similar they really are yet. c. The mating rituals of bacteria have not been studied enough. d. Bacteria reproduce asexually. e. Bacteria are all too different to be considered similar.
d. Bacteria reproduce asexually.
All of the following are examples of inclusion bodies in prokaryotic cells except __________. a. Magnetosomes b. Glycogen granules c. Carboxysomes d. Endospores
d. Endospores
During lytic replication of bacteriophage, which process uses factors from the host cell, rather than coded by the viral genome? a. Proteins to copy the viral genome b. Lysozyme to rupture the host cell c. Proteins to build new phage particles d. Enzymes which transcribe and translate viral genes e. DNAases to break up the host cell genome
d. Enzymes which transcribe and translate viral genes
You have isolated a new organism which has eukaryotic cells, is multicellular, grows as hyphae, does not perform photosynthesis, and has a cell wall. This organism most likely belongs to which kingdom? a. Protista b. Bacteria c. Archaea d. Fungi e. Either Fungi or Protista
d. Fungi
Choose the true statement regarding Lister's contribution to health care. a. He was the first to recommend hand-washing to decrease infection rates in patients. b. He disproved spontaneous generation. c. He established innovations in nursing practices. d. He developed aseptic surgery practices.
d. He developed aseptic surgery practices.
A young patient who underwent surgical placement of depth electrodes for epilepsy treatment contracted a prion disease. Cortical electrode probes are known to be reused in patients. Based on this information, which of the following prion diseases did the young patient most likely contract? a. Inherited Creutzfeldt-Jakob Disease b. Sporadic Creutzfeldt-Jakob Disease c. Variant Creutzfeldt-Jakob Disease d. Iatrogenic Creutzfeldt-Jakob Disease
d. Iatrogenic Creutzfeldt-Jakob Disease
Why are most prokaryotic cells small? a. A low surface area-to-volume ratio helps smaller cells divide easier. b. A high surface area-to-volume ratio helps smaller cells divide easier. c. Intracellular inclusions demand that cell size be small. d. Nutrient diffusion is most efficient for smaller cells. e. Storage bodies within a cell enable cells to be small so they need less nutrients.
d. Nutrient diffusion is most efficient for smaller cells.
Which of the following is a valid difference between the leading and lagging strands in DNA replication? a. Helicase opens the leading strand of DNA at a faster rate than the lagging strand of DNA. b. Following DNA replication, RNA primers are fully removed by the enzyme DNA ligase. c. On the leading strand, DNA polymerase III replicates DNA from 5' to 3', whereas on the lagging strand DNA polymerase I builds DNA from 3' to 5'. d. On the leading strand, only a single RNA primer is needed to initiate continuous DNA synthesis.
d. On the leading strand, only a single RNA primer is needed to initiate continuous DNA synthesis.
Which of the following infectious agents usually requires an immune-compromised person to establish an infection? a. True pathogen b. Re-emerging pathogens c. A normal virus d. Opportunistic pathogen
d. Opportunistic pathogen
Choose the statement which BEST defines a pleomorphic organism. a. Pleomorphic organisms lack the ability to take on different forms such as shape or arrangement. b. Pleomorphic organisms can alter their size but not their shape. c. Pleomorphic organisms do not impact an organism's ability to form a biofilm. d. Pleomorphic organisms can take on different forms, which enhances their survival and transmission to a human host.
d. Pleomorphic organisms can take on different forms, which enhances their survival and transmission to a human host.
Which of the following would not move freely across the cytoplasmic membrane? a. Dissolved carbon dioxide b. Small alcohols c. Dissolved oxygen d. Positively charged hydrogen ions
d. Positively charged hydrogen ions
Which of the following is a key difference between lytic and lysogenic bacteriophage replication cycles? a. Lysogenic bacteriophages release via host cell lysis, whereas lytic bacteriophages bud off from the host cell membrane. b. Lytic replication requires an uncoating step, whereas in lysogenic replication, the bacteriophage's nucleic acid is directly injected into the host cell. c. Whereas lytic replication enables the infection of several hosts, lysogenic replication only allows for infection of a single host cell. d. The lytic replication cycle ends with host cell lysis and release of newly formed bacteriophage particles, whereas lysogenic replication leads to prophage formation.
d. The lytic replication cycle ends with host cell lysis and release of newly formed bacteriophage particles, whereas lysogenic replication leads to prophage formation.
One ml of a liquid suspension of bacteriophage is mixed with its host bacteria and plated. After incubation, the plate is completely clear. What is the probable explanation? a. The bacteriophage culture was dead b. The phage concentration was too low to infect many bacterial cells c. The bacteria mutated and could no longer be infected by this phage d. The phage concentration was so high that all the host bacterial cells were killed e. The bacteriophage doesn't grow on the type of agar used
d. The phage concentration was so high that all the host bacterial cells were killed
RNA is distinguished from DNA because only RNA: a. Is composed of nucleotides that contain the nitrogen bases T, C, G, and A. b. Has a 3' to 5' directionality. c. Is composed of nucleotides that contain the sugar deoxyribose. d. Typically exists as a single-stranded molecule.
d. Typically exists as a single-stranded molecule.
In a dehydration synthesis reaction, macromolecules are built when ________ is removed to form a covalent bond. a. Carbon dioxide b. Oxygen c. An electron d. Water e. An amino acid
d. Water
How is osmosis different from simple diffusion? a. Water requires energy to move across a cytoplasmic membrane. b. Water requires a special permease. c. Water cannot pass freely across the membrane. d. Water movement is driven by the concentration of solutes rather than its own concentration.
d. Water movement is driven by the concentration of solutes rather than its own concentration.
Viral genetic reassortment is most likely to occur when __________.
different viral strains infect the same cell
A sample obtained from a patient's throat was inoculated on blood agar. After 24 hours, there was a clear yellow zone covering the area of growth. The medium used was _________ and the organism is said to be _________.
differential; beta hemolytic
Prokaryotes tend to be small because they rely on _________ of nutrients.
diffusion
What is the order of the taxonomic hierarchy from least specific to most specific?
domain, kingdom, phylum, class, order, family, genus, species
Used in conjunction with standard precautions, __________ are used to reduce the spread of an agent that is communicated through large moist respiratory droplets that do not remain suspended in the air, and therefore require closer contact for transmission.
droplet precautions
Which of the following would not be important when evaluating measures of association?
duration of the disease
Normal microbiota colonize our skin, and areas of the digestive, genital, urinary, and respiratory systems. If disruption in the balance of normal microbiota occurs, opportunistic pathogens can cause illness. ___________ is defined as a disruption of normal microbiota balance
dysbiosis
Which factors may result in a normal microbiota species causing disease?
dysbiosis due to antibiotic therapy or invasion of other tissues by the microbiota species
Which description of antigenic drift and antigenic shift in the influenza virus is INCORRECTLY matched? a. Antigenic shift: Often leads to viral strains with new features such as increased infectivity or expanded host range. b. Antigenic shift: May result in a pandemic outbreak due to widespread lack of immunity. c. Antigenic drift: A host vaccinated against an influenza strain before antigenic drift may lack effective immunity and be susceptible to infection. d. Antigenic drift: Spontaneous mutation leads to a minor change in HA or NA spikes. e. Antigenic drift: Often involves reassortment of viral strains in an animal host followed by a "species jump" to humans.
e. Antigenic drift: Often involves reassortment of viral strains in an animal host followed by a "species jump" to humans.
Carriers of the sickle-cell gene a. Are often found in high concentrations in U.S. cities. b. Are more likely to die from a malaria infection. c. Experience painful changes in nerve cell shape. d. Are more susceptible to contracting malaria. e. Have a survival advantage in areas where malaria is common.
e. Have a survival advantage in areas where malaria is common.
Prions are a. Diagnosed with a simple blood test b. Associated with many tissue types c. Living, acellular entities d. Infectious nucleic acids e. Misfolded proteins which can cause normal versions to also misfold
e. Misfolded proteins which can cause normal versions to also misfold
Bacteria with flagella distributed all over the cell surface are described as having: a. Amphitrichous flagella b. Monotrichous flagella c. Lophotrichous flagella d. Periplasmic flagella e. Peritrichous flagella
e. Peritrichous flagella
Which of the following are contributors to viral genome evolution? a. Quick replication time and superior proofreading by RNA polymerases compared to DNA polymerases b. The large number of virions released within a host c. Quick replication time d. Superior proofreading by RNA polymerases compared to DNA polymerases e. Quick replication time and the large number of virions released within a host
e. Quick replication time and the large number of virions released within a host
Which type of vesicle/vacuole is INCORRECTLY matched with its description? a. Lysosome: Contains hydrolytic enzymes that break down substances engulfed by the cell b. Peroxisome: Protects the cell from hydrogen peroxide and other toxic oxygen intermediates c. Transport vesicle: Moves substances to diverse cellular destinations within the cell d. Vacuole: Contains water and substances such as nutrients, toxins, or waste products e. Secretory vesicle: Replenishes the lipid bilayer and deliver proteins for incorporation into the membrane
e. Secretory vesicle: Replenishes the lipid bilayer and deliver proteins for incorporation into the membrane
Which of the following can be determined using simple stains? a. The number and position of flagella b. The presence of capsules c. Size and shape d. The presence of endospores e. Size, shape and cellular arrangement
e. Size, shape and cellular arrangement
Which property is not used to classify viruses? a. Genome architecture b. Type of nucleic acid present c. Capsid symmetry d. Presence or absence of an envelope e. Tissue types infected
e. Tissue types infected
When electrons are removed from nutrients via an oxidation reaction, the coupled reduction reaction may be
either FAD → FADH2 or NAD+ → NADH.
NADH and FADH2 play an important role in energy production by donating electrons for redox reactions that occur in the ___________.
electron transport chain
The common cold is a(n) _________ disease.
endemic
What occurs when a high energy bond in ATP is broken resulting in ADP?
energy is released that will drive chemical reactions
What occurs when a high-energy bond in ATP is broken resulting in ADP?
energy is released that will drive chemical reactions
What are the three factors of the epidemiological triangle?
environmental factors, etiological agent, and host factors
In DNA replication, protein factors are more heavily required for replication in __________.
eukaryotic cells
In order to harvest energy from polysaccharides, lipids or proteins, cells must use ________ to break down these large macromolecules extracellularly before bringing them into the cell.
exoenzymes
Botulism is caused by ingesting _________.
exotoxins
Researchers attempting to determine the effect of a treatment for disease are engaged in _________ studies
experimental
A double-blind, randomized study is being used to test the effectiveness of a new drug that targets the multi-drug resistant bacterium Clostridium difficile. Infected participants in the study were given either a placebo or the test drug and then monitored for one month for clearance of infection. This type of study can best be characterized as a(n)_________________.
experimental study
Which group of microbes prefers using oxygen but can survive without it?
facultative anaerobe
Although Staphylococcus aureus can grow at 7% NaCl, it grows best at NaCl levels less than 1%. This organism is a __________.
facultative halophile
When preparing growth media for Enterococcus durans, one must add amino acids, vitamins, and other growth factors in order for the organism to grow properly. This organism is said to be _________.
fastidious
Which of the following methods would be best for sterilizing a sample of a heat-sensitive solution?
filtration
Chlorine usually exists as the anion Cl- because it has __________.
gained an electron.
Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?
glucose
Pyruvic acid is utilized during various fermentation processes. What process produces pyruvic acid that fuels fermentation?
glycolysis
Which of the following pathways are operational in a cell growing via fermentation?
glycolysis