Arrange the following in the proper sequence in which they occur during a single PCR cycle.
1. Heat separation of strands of target DNA
2. Complementary base pairing between primers and target DNA
3. Addition of DNA nucleotides by Taq DNA polymerase
Place the steps of F plasmid transfer in the correct order:
1. F pilis makes contact with a recipient cell
2. One strand on the F plasmid is cut at the origin of transfer
3. Single-stranded is transferred to the recipient cell
4. Complement of the transferred strand is synthesized
Which is true of the transitional step in the central metabolism?
-CO2 is removed from pyruvate
-Electrons are transferred to NAD+, reducing it to NADH + H+
-The 2-carbon acetyl group is joined with coenzyme A to form acetyle-CoA
What is true about a crown gall tumor?
-It is due to the incorporation of bacterial plasmid DNA into the plant chromosome
-It is a bacterial infection of plants
-It requires a plasmid
-It produces a large amount of opines that neither the plant nor bacteria synthesizes
The lac repressor in the absense of lactose
-Active and can bind to the operator
Which of the following are valid concerns for genetic engineering and other DNA technologies?
-Spread of herbicide resistant gene to weeds
-Misuse of personal DNA sequence data
-Evolutionary relatedness of organisms
-The process of arranging organisms into similar or related groups for study
-The system of assigning names to organisms
-The process of characterizing an isolate to determine the group to which it belongs
Stop codons for DNA translation include
Concerning catabolism and anabolism
-The intermediates of one serve as the reactants in the other
-The energy gathered in catabolism is utilized in the anabolism
Which is not a reason why rRNA sequences are so useful in microbial classification and identification?
-The sequences are very different, which makes it easier to distinguish between closely related microbes
In conjugation the donor cell is recognized by the presence of
-an F plasmid
Most vectors used today have a multiple cloning site. The reason for this is
-To allow DNA fragments cut with different restriction sites to be cloned
-Carries amino acids to the growing peptide chain during translate
-Contains the genetic information decoded during translation
-Components of ribosomes
-Regulates gene expression
Removing the electron transport chain of E. coli would
-Prevent oxidative phosphorylation
During enzymatic reaction, a non-competetive enzyme inhibitor would bind to the enzyme's _____
Please use the dichotomous key below to identify a bacterium with the following characteristics: stains purple in the Gram stain, produces bubbles when placed in hydrogen peroxide, and coagulate plasma.
PCR can be used to
-All of these
-Amplify DNA to detectable levels
Which of the following describe the Ames test correctly?
-It is a method that uses bacteria to test if a given chemical can cause mutations in DNA
-The test uses bacteria that cannot make their own histidine
-Nucleic acids produced during discontinuous synthesis of lagging strand of DNA
-Enzyme that temporarily breaks the strands of DNA relieving the tension caused by unwinding the two strands of DNA helix
-Enzyme that joins two DNA fragments together by forming a covalent bond between the sugar and phosphate residues
-Enzyme that synthesizes small fragments of RNA
-Enzyme that unwinds DNA helix at the replication fork
If a 75 base-pair fragment of double-stranded DNA has 25 cytosines in it, how many adenines would you expect it to have?
A pathogenic strain of E. coli acquired a toxin from another bacterial species. However, there was no direct-contact between the bacterial cells. This is likely due to
Compound A lost a pair of electrons to compound B during a chemical reaction
-Compound A is being oxidized, compound B is being reduced
Which of the following is FALSE about transposons?
-They are capable of moving independently from one cell to another cell
Which of the following correctly describe the degeneracy of the genetic code?
-The third position of the codon is sometimes not important in determining which amino acid a codon encodes
-An amino acid can be coded by several codons
-More than one codon can code for an amino acid
In the figure, the probes in A do not bind to the denatured DNA because
-They are not complementary to the unknown DNA
Which is NOT commonly found in a cloning vector?
-Restriction enzyme genes
After the completion of DNA replication and cell division in prokaryotic cells
-each daughter cell contains DNA with one newly synthesized DNA strand and one original parental strand
-Both daughter cells have identical copies of DNA
Which is NOT a step in generating recombinant DNA molecules?
-RNA polymerase is used to copy the gene of interest in genomic DNA
Which of the following are correct regarding Restriction Enzymes?
-The evolved as a defense mechanism against bacterial viruses
-DNA fragments produced by restriction enzymes can be ligated together
-Are also called exonucleases
The process of DNA translation includes all but
Which of the statements about DNA and RNA in prokaryotes and eukaryotes are FALSE?
-Eukaryotic mRNA is typically polycistronic
-RNA polymerase requires a primer
Which of the following would be the correct scientific name?
-Homo sapiens (in italics)
Order the following taxonomic categories from the most inclusive to the lease inclusive
Bases in the nucleotides can be alkylated by mutagens. For example, methyguanine can sometime basepair with T instead of C, leading to mutations during replication. If methylguanine replaces guanine in a DNA strand with the sequence 5' CGA 3', which of the following are possible complementary strand after DNA replication
Consider how an aerobically respiring bacterial cell uses glycolysis, the TCA cycle, and oxidative phosphorylation to break apart and oxidize glucose. What are the three main benefits these central metabolic pathways yield to the cell?
-ATP, reduced electron carriers, and precursor metabolites
Influenza viruses bud from the host cell. Based on this information, the viruses most likely
-May grow as mycelia or yeast
-Are often associated with disease in humans and animals
Place the steps in interferon (IFN) response in the correct order
1. A cell detects viral RNA and produces IFNs
2. IFN diffused out of the infected cell and attaches to receptors on healthy neighboring cells
3. IFN stimulates healthy neighboring cells express inactive antiviral proteins
4. Inactive antiviral proteins become activated by the presence of viral dsRNA in the newly infected cell.
5. Activated antiviral proteins degrade mRNA
Place the statements about B-cell activation in the correct order:
1. B cell receptors bind to antigens
2. Antigens are internalized and digested into peptide fragments
3. Peptide fragments are displayed on MHC class II molecules
4. T helper cells recognize antigen-MHC complexes
5. T helper cells deliver cytokines to naive B cells
6. Activated B cells proliferate and differentiate into plasma cells and memory cells
Which causes uncontrolled growth of plant tissue, resulting in a tumor?
Several inherited deficiencies in the complement system occur in humans. Which of the following would be the MOST severe?
-deficiency of C3
Arrange the following steps of viral infection in the correct order
2. Uncoating of the capsid
3. Biosynthesis of proteins and nucleic acids
4. Virion assembly
Skin and mucous membranes
-Are the first line of innate immunity
-Act as physical barriers to infection
-Contain antimicrobial secretions
Valley fever is
-A fungal disease
-Caused by Coccidioides sp.
Which of the following statements about fungi are FALSE?
-Fungi can be photosynthetic
What definitely set viruses apart from other organisms?
-Viruses replicate by assembly
-Viruses are not made of cells
Which of the following are likely to live on dry and salty surfaces?
Members of this group of microbes can break down glycogen deposited in the vaginal lining in response to estrogen. This helps to drop the pH in the area, preventing infections.
-Lactic acid bacteria
The primary purpose of asexual spores is _____ and the primary purpose of sexual spores is _____.
-Dispersal, survival or dormancy
Which of the following statements about innate immunity is true?
-Toll-like receptors recognize molecules derived from pathogens.
The earliest oxygenic phototrophs are thought to be
Which of the following is/are obligate intracellular parasites?
-Chlamydia and Rickettsia
-most abundant class produced but most are secreted to mucus, tears, and saliva. Also found abundant in milk
-Binds to mast cells and basophils and involved in many allergic reactions
-Most abundant class in blood serum, cross placenta and offer protection to developing fetus
-Pentamer, first class of antibody produced in the primary response
Viruses may NOT be cultivated in
-Cell-free complex medi
Which of the following is NOT a reason that oncogenic viruses contribute to cancer development?
-Viruses may carry tumor suppressor genes
Why are eukaryotic pathogens of animals more difficult to treat than prokaryotic pathogens?
-Eukaryotic pathogens are more similar to host cells
-Able to multiple because they have encountered an antigen they recognize and have received signal confirming that the antigen requires a response
-Long-lived descendants of activated lymphocytes
-Descendants of activated lymphocytes that are armed with protective abilities
-Lack fully developed antigen-specific receptors
-Have antigen-specific receptors
Members of the family Enterobacteriaceae
-Often reside in the intestinal tract of humans and animals
-Include E. coli, Enterobacter, Salmonella, and Shigella
-Are facultative anaerobes
A macrophage works by ____, while a neutrophil works by ____?
-Ingesting microbes and destroying them internally, ingesting microbes and also releasing toxic granule component
-Inhibits bacterial growth
-Speeds up the body's reactions
Inactivation of a cell's interferon genes would likely have which outcome?
-The cell would no longer alert neighboring cells to respond to a viral infection.
Select all of the following that apply to a primary antibody response to a T-dependent antigen
-Takes 10-14 days to build a substantial amount of antibodies in the bloodstream
-Produces mainly IgM antibodies, but undergoes class switching to other classes near the end of the response
T cells and B cells develop from stem cells in red bone marrow, but T cells mature in the ____ while B cells mature in the _____.
-Thymus, bone marrow
The Gram-negative bacterium that can break down urea and causes stomach ulcers is
What is a component of innate immunity?
The ability to exist as either a trophozoite or a cyst is characteristic of many
Viroids can best be described as
-Naked infectious RNA, which can self-replicate in a host cell
A bacterium being examined in a microbiology laboratory is found to be lysogenized by phage A. Which of the following statements is TRUE?
-The bacterium is immune to reinfection by phage A but susceptible to infection by phage B
Which of the following statements regarding lichens is FALSE?
-Lichens represent a parasitic relationship between a fungus and an alga or cyanobacterium
All of the following fungal spores are produced sexually except
Which of the following events DOES NOT occur after T-cell activation?
-Neutrophils become more powerful
The Gram-positive rod that is also acid-fast and is a human pathogen is
Which statement regarding bacteria is FALSE?
-Lactobacilli can grow easily on a nutrient agar in the presence of oxygen
Which statement DOES NOT describe activation of innate immune responses by pattern recognition receptors (PRRs) correctly?
-PRRs recognize molecules derived only from pathogens outside of a cell
Algae differ from protozoa in that
-Algae carry out photosynthesis while protozoa cannot
Which statement about prions are correct?
-Prion proteins are normally found within the body as PrPC (cellular prion protein) and are not harmful
-Abnormal prion (PrPSc) can change a normal PrPc into an abnormal prion causing a chain reaction
-Prions are proteinaceous infectious particles
Which of the following is NOT a characteristic of B cells?
-They recognize antigens associated with MHC I
A virion is composed of
-Protein, either RNA or DNA, and possibly lipid
Complement system activation
-Immune complexes activate complement proteins
-Antibodies bind to the surface receptors on microbe to prevent attachment to the host
-Coating of microbe with antibody to enhance phagocytosis
-Formation of large Ab-Ag complexes as a result of the Ab binding two separate antigens
Antibody-dependent cellular cytotoxicity (ADCC)
-IgG molecules attach to a cell targeting it for attack by a NK cell
Are all fungi detrimental (bad) for other organisms?
-No-fungi are sometimes good, sometimes bad for other organisms. It really depends on which fungus you're talking about and the relationship it has with the other organism. Some fungi, for example, can form a symbiotic relationship with plant roots that increases their nutrient and water absorption. This is good.
-Replication and gene expression follow the central dogma of molecular biology
-Carry an RNA-dependent RNA polymerase in their visions
Single-stranded (+) sense RNA viruses
-Vial genome can be translated directly by host ribosomes
-Carry an RNA-dependent DNA polymerase in their visions
Single-stranded DNA viruses
-Copies of progeny viral genome are made from a dsDNA template
If your cell-mediated immune response were compromised, which of the following would happen?
-You would be more susceptible to infections by viruses
The best possible analogy available below for the way in which variable (V), diversity (D), and joining (J) antibody gene segments get put together to create the diversity possible in hypervariable regions is
-to think of the various segments as a bingo game-each segment is randomly selected but you're going to need one of the V, D, and J to form a functional molecule. The right combination varies depending on which antigen is eventually going to be binding to the molecule (i.e., your bingo card would be the eventual antigen, and the random calling out of the number/letter combinations would be the forming of the VDJ hypervariable region).
Which DOES NOT describe protozoa correctly?
Ingest inorganic materials as main food source
Negative staining is commonly used to determine if bacterial cells have
Which molecule is responsible for displaying fragments of proteins made within the cell and would therefore be useful in detecting a virally infected cell?
Which of the following statements about symbiosis are FALSE?
Only one partner in a symbiotic relationship is benefited.
Parasites are not in a symbiotic relationship with their host.
Members of a symbiotic relationship cannot live independently.
neutralized by antitoxin
can be highly specific
may cause cell lysis
may hydrolyze phospholipids
can be used in a toxoid vaccine
may activate helper t cells
protein in nature
produced by Gram-postive and Gram-negative bacteria
synthezed in cytoplasm, sometimes secreted.
Denatured by heat.
Mostly very potent.
unaffected by heat
composed of lipid A
cause fever and shock
cannot be used in a toxoid vaccine
activate B cells
part of cell structure.
Lipopolysaccharide in nature.
made by gram-negative cellos only
component of outer cell membrane.
unaffected by heat
no very potent unless systemic.
How does cytomegalovirus avoid the cellular immune response?
producing fake MHC class I molecules that NK and Tc cells do not recognize
A patient is suffering from a severe case of influenza, caused by influenza virus. He takes analgesics (painkillers) and also a fever-reducing medication, and after a few days begins to feel better. However, just as he thinks he will be able to return to school, the patient suddenly worsens, developing chest pain, and a productive cough (coughing up sputum). When he notices that his sputum contains blood, he goes to the doctor who diagnoses pneumonia, caused by the bacterium Streptococcus pneumoniae. In this scenario, the influenza virus is ______ while the S. pneumoniae is _______.
a primary pathogen; a secondary pathogen
Which of the following is a mechanism used by pathogens for avoiding antibodies?
Some people consider Staphylococcus aureus to be a primary pathogen, while others classify it as an opportunist. Which of the following statements supports the opinion that it is an opportunist?
S. aureus is found in the nasal passages of many healthy people.
Which of the following statements about A-B toxins is FALSE?
A-B toxins cause TH cell stimulation, leading to a cytokine storm.
Entry through an insect bite
Entry through directed macrophage uptake
Entry through a wound
Entry through induced endocytosis
Entry through intestinal M cells
M cells in the intestinal epithelium are important because pathogenic bacteria such as Shigella species
use them to gain access to underlying tissue
Consider the figure of a virus infected cell. By directing the host cell to synthesize fake MHC class I molecules, the virus is
making sure its host is not destroyed by TC cells or NK cells.
Consider the figure of a lichen. In this symbiotic relationship, the photosynthetic alga provides the fungus with organic nutrients. The fungus provides the alga with water and protection. Which of the normal microbiota relationships described below is most similar to this association?
Mutualism - intestinal bacteria providing host with vitamins E and K.
Which of the following is NOT a mechanism used by pathogens for avoiding opsonization?
Producing C5a peptidase
Please place the four steps of Koch's postulates in the correct order as they would normally be applied.
1. Find evidence that a particular microbe is present in every case of a particular disease
2.Isolate the suspected microbe from an infected host and cultivate it in pure culture in the laboratory.
3. Inoculate a susceptible healthy subject with the pure culture of the potential pathogen and observe the resulting disease.
4.Reisolate the disease agent from the test subject which now shows signs of disease
Antibodies, which are produced as part of the adaptive immune response, can sometimes be damaging rather than beneficial. People suffering from an autoimmune disease called antiphospholipid antibody syndrome (APS) make antibodies that bind to phospholipids. Some of the signs and symptoms affected individuals experience are blood clots, stroke, heart attack, and kidney damage. What is the likely cause of these symptoms?
Cell damage caused by binding of these antibodies initiates inappropriate coagulation events which interfere with blood flow in affected organs.
Which of the following is NOT a mechanism used by pathogens for avoiding or surviving phagocytosis?
Inhibiting phagocyte chemotaxis
Which of the following is/are mechanisms pathogens use for avoiding recognition and attachment by phagocytes?
producing a capsule that binds the hosts complement regulatory proteins.
producing receptors that allow binding of Fc region of antibodies and prevent opsonization.
Producing M protein for inactivating component component C3b.
Inactivating component component C3b.
Choose the best definition of an opportunistic pathogen.
An organism that only causes disease when the host's immune defenses are compromised.
Consider the figure below and check all the TRUE statements.
A pathogen that lost the ability to produce adhesins would no longer cause disease.
If a host cell lacks receptors for a particular adhesin, that cell is protected from infection by the pathogen.
Although bacteria can bind to host cell receptors, the receptors have other specific functions for that cell.
required several injections.
cannot cause disease.
contains inactivated viruses.
also known as Salk vaccine.
stimulates igA production.
Gives mucosal protection.
provides herd immunity
may cause disease.
Also known as Sabin vaccine.
Which of the following would be most important in establishing herd immunity?
Inoculating people with measles vaccine.
The chickenpox vaccine is not recommended for someone who has AIDS or a similar immunodeficiency. Based on this information, you conclude that the vaccine likely
contains an attenuated strain.
The Hib vaccine (Hib = Haemophilus influenza type b) is specially constructed so that an infant's immune system will mount an immune response against the bacterium's capsule. Based on this info, the vaccine is likely a
Which the following is an advantage of an oral vaccine over an injected one? Oral vaccines
elicit a strong IgA response.
The signs and symptoms of the disease tetanus include muscle spasms and paralysis. The disease is caused by Clostridium tetani, a bacterium that produces a toxin called tetanospasmin. Considering these facts, a protective vaccine against tetanus would contain
If you had to test 75 patients for antibodies to Bacillus anthracis (causative agent of anthrax), which immunoassay would you use?
When labeled rabbit anti-human antibody is used in an ELISA, the antibody binds directly to
the protein of interest.
Which of the following diseases that cause childhood deaths or disabilities are now prevented with successful vaccination? Check all that apply.
All of the following are matching pairs EXCEPT
fluorescent antibody test - microtiter plate.
A patient has a genital lesion. The physician suspects syphilis, caused by the bacterium Treponema pallidum. Which of the following could be used to confirm
testing fluid from the patients lesion for bacteria that bind to known T. Palladium antibodies
Testing fluid from the patients lesion for bacteria that bind to known T palladium antibodies
Which of the following would result in the production of memory cells?
Artificial active immunity
natural active immunity
The figure below shows a test used to determine antibody titer. The wells with a small red dot show a negative reaction while those with a large red dot show a positive reaction. What is the antibody titer in this test?
Which of the following is an example artificial active immunity?
A child who has been inoculated with the chickenpox vaccine.
Pathogen may revert to virulence
contain live, weekend pathogen
Elicit long-lasting immunity
Pathogen multiplies in the vaccine recipient
may cause disease in immunocompromised
usually not given to pregnant women
require refrigeration to keep activity
Example: MMRV vaccine
Pathogen never reverts to virulence
Elicit weaker immune response
Pathogen does not replicate in recipient
Booster doses required to maintain immunity
Safe for pregnant women
Pose no risk to immunocompromised
Example: Hepatitis A vaccine
Contain adjuvants for increased immunity