Microbiology Exam 2

- Complement - Inflammation - Chemical Barrier

- A series of proteins that assemble into a structure known as MAC (membrane attack complex) - A non-specific reaction including localized or systemic reaction involving redness, heat, swelling and pain - Acid in the stomach, acidic environment of the vagina

- DNA Ligase - DNA Polymerase - Restriction Endonuclease

- An enzyme that forms the missing phosphodiester bonds within the DNA, sealing the gaps - an enzyme that extends the primer, forming new DNA chain - an enzyme that cuts DNA in special sequences forming sticky ends

- Self Tolerance - Memory - Specificity

- acquired inability to react to self antigens - ability to mount a secondary immune response due to memory cells - ability to mount an immune response which is specific to a pathogen

- Coagulase - Endotoxin - Capsule

- an enzyme that causes production of blood clots inside the host - lipopolysaccharide, part of the outer membrane of gram-negative bacteria - outer coat consisting of a dense, mucus polymer layer surrounding a cell and used in attachment

- Specialized Transduction - Generalized Transduction - Conjugation

- the bacteriophages pick up only specific portions of the host's DNA., results in a highly efficient transfer - the bacteriophages can pick up any portion of the host's genome, low efficiency of transfer - involves direct contact and transfer DNA through a pilus

________ is a group of sequentially interacting proteins important in innate and adaptive immunity. A) A complement B) An opsonin C) An inflammation D) A regeneration

A) A complement

The enzyme that covalently links both strands of a vector and a DNA insert (a gene of interest) in molecular cloning is A) DNA ligase. B) DNA phosphatase. C) DNA hydrolase. D) DNA transferase.

A) DNA ligase.

Which time period(s) during PCR thermocycling is/are hottest in temperature? A) During DNA denaturation B) During primer annealing C) During primer extension/elongation D) Both the first and last cycles are hotter in temperature than all other cycles.

A) During DNA denaturation

Which of the following is NOT important for the adherence of bacteria to host tissues? A) Lipopolysaccharides B) Capsule C) Adhesins D) Slime layer

A) Lipopolysaccharides

What occurs when an inducer is added to an environment containing an organism with a metabolic pathway controlled by a repressor? A) The inducer combines with the repressor and activates the pathway. B) The inducer combines with the repressor and inactivates the pathway. C) The inducer combines with the substrate and blocks induction. D) The inducer does not combine with, but functions as a chaperone molecule for, the enzyme-substrate complex.

A) The inducer combines with the repressor and activates the pathway.

Genetic engineering of plants involves what types of vectors? A) Ti-plasmid based vectors B) pUC 19 based vectors (used for Ecoli) C) Retrovirus based vectors (used for human gene therapy)

A) Ti-plasmid based vectors

The principle behind nucleic acid probe design is that the probe itself must contain A) a key complementary part of the target gene sequence of interest. B) all of the nucleotide sequence of the gene of interest to conclusively identify the gene. C) an antibody to specifically bind to the gene of interest. D) at least five separate complementary regions of the gene of interest.

A) a key complementary part of the target gene sequence of interest.

An outer coat consisting of a dense, well-defined polymer layer surrounding a cell made of polysaccharides and used in attachment is called a A) capsule. B) cytoplasmic membrane. C) lipopolysaccharide layer. D) pilus

A) capsule.

The F (fertility) plasmid contains a set of genes that encode for the ________ proteins that are essential in conjugative transfer of DNA. A) pili B) SOS repair C) transduction D) transformation

A) pili

The uptake of free DNA from the environment is referred to as ________, while the transfer of DNA with direct cell-to-cell contact is known as ________. A) transformation / conjugation B) transduction / conjugation C) conjugation / transformation D) transformation / transduction

A) transformation / conjugation

The body's noninducible, preexisting ability to recognize and destroy a variety of pathogens or their products is called A) adaptive immunity. B) innate immunity. C) phagocytosis. D) cytotoxic response.

B) innate immunity.

The lac operon is an example of ________ control in which the presence of an ________ is required for transcription to occur. A) negative / activator B) negative / inducer C) positive / activator D) positive / inducer

B) negative / inducer

Cells that can engulf foreign particles, and can ingest, kill, and digest most bacterial pathogens are called A) red blood cells. B) phagocytes. C) reticulocytes. D) resistant cells.

B) phagocytes.

In one step of cloning, the gene of interest is inserted inside the vector (e.g., a plasmid-based vector pUC 19 ), at a specific site, located on the lacZ gene. Cells that have "insertional inactivation" of the lacZ gene are A) blue. B) white. C) yellow. D) fluorescent green

B) white.

Which of the following is a likely target for a toll-like receptor (TLR)? A) Tumor necrosis factor B) Interleukin IV C) Flagellin D) Insulin

C) Flagellin

Which mutations might result in the most detrimental impact on the host? A) Base-pair substitution mutation B) Silent mutation C) Frameshift mutation D) Missense mutation

C) Frameshift mutation

An organism grown in nutrient rich broth to high turbidity always produces a blue pigment. When a large inoculum is transferred to a nutrient rich agar plate, it also appears blue. A researcher noticed that this never happens when very small colonies are grown on low nutrient agar plates, however. What is the most plausible conclusion? A) Large populations enabled the differentiation of a subpopulation of cells that created the blue pigment. B) Only high nutrient conditions provide enough energy for cells to produce this secondary metabolite that appears blue. C) Production of the blue pigment production is linked to quorum sensing. D) The strong gradient from very high to low nutrient bioavailability induces production of the blue metabolite.

C) Production of the blue pigment production is linked to quorum sensing.

Which type of regulator(s) specifically binds to operator regions of DNA? A) Activators B) Activators and inducers C) Repressors D) Repressors and corepressors

C) Repressors

Diphtheria toxin is A) a type of endotoxin. B) a cytolytic toxin. C) an AB toxin. D) a superantigen toxin.

C) an AB toxin.

Pattern recognition receptors are most directly used A) by all lymphocytes to trigger degranulation during allergic response B) by neutrophils to tell self-tissues C) by phagocytes to detect pathogens. D) by B cells to produce antibodies.

C) by phagocytes to detect pathogens.

What makes eukaryotic transcripts easier to isolate than bacterial transcripts? A) Eukaryotic transcripts are not methylated but their genes are often methylated. B) Larger transcript size in eukaryotes enables easy size-selection methods. C) mRNA is polyadenylated in eukaryotes. D) Transcripts are the most abundant RNAs in eukaryotes.

C) mRNA is polyadenylated in eukaryotes.

What is the difference between adherence and colonization? A) Colonization occurs when transient microbes are on a tissue, whereas adherence is a more permanent attachment to cells. B) Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes initially attach. C) Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes first begin to reproduce in the host tissues. D) Colonization occurs when a microbe begins to grow in host tissues, whereas adherence occurs when the microbe initially attaches.

D) Colonization occurs when a microbe begins to grow in host tissues, whereas adherence occurs when the microbe initially attaches.

Which of the following are NOT phagocytes? A) Dendritic cells B) Monocytes C) Neutrophils D) Erythrocytes

D) Erythrocytes

A ʺpoint mutationʺ refers to mutations involving A) a base-pair substitution. B) the addition of a base pair. C) the deletion of a base pair (microdeletion). D) a substitution, deletion, or addition of one base-pair.

D) a substitution, deletion, or addition of one base-pair.

Cytolytic toxins A) are extracellular proteins. B) cause cell lysis and death. C) damage host cytoplasmic membrane. D) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane.

D) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane.

The Tat system is involved in A) protein synthesis. B) transcriptional initiation. C) protein folding. D) protein secretion

D) protein secretion

Regulatory proteins (select the BEST answer) A) are influenced by small molecules. B) bind to specific DNA sites. C) regulate transcription. D) regulate transcription, bind specific DNA sites, and can be influenced by small molecules (all of the above).

D) regulate transcription, bind specific DNA sites, and can be influenced by small molecules (all of the above).

The spread of pathogens through the blood and lymph systems that results in a bloodborne systemic infection is called A) bacteremia. B) cancer. C) pathogenesis. D) septicemia.

D) septicemia.

All of the following are functions of heat shock proteins in bacteria EXCEPT A) prevention of inappropriate protein subunit aggregation. B) degradation of denatured proteins. C) responding to exposure to high levels of ethanol. D) stimulation of binary fission.

D) stimulation of binary fission.

A type of immunity that results from the actions of special T cytotoxic cells that attack body cells infected with the virus or intracellular pathogen called Cell mediated immunity. True False

True

Some proteins that bind to DNA (within the operon) to block transcription, whereas other proteins bind to a different site on the operon to activate transcription. True False

True

The stringent response is a mechanism used by bacteria that provides increased ability to survive in environments lacking nutrients. True False

True

secretion systems can either help cells to excrete products to the outside or into the neighboring cells. True False

True

Which of the following are proteins that interact directly with antigens during the adaptive immune response? a. Immunoglobulins, MHC, T cells b. Immunoglobulins and T cells c. none of the above d. T cells only e. Immunoglobulins only

a. Immunoglobulins, MHC, T cells

Botulinum toxin causes a. muscles to be unable to contract b. muscles to be unable to relax. c. has no effect d. vomiting e. severe diarrhea.

a. muscles to be unable to contract

The genes encoding green fluorescent protein (GFP) and β-galactosidase are typically used in cloning as a. reporter genes. b. global control genes. c. transcription regulators. d. promoter sequences.

a. reporter genes.

Which of the following is a way to prevent attenuation (weakening) of a pathogen and maintains its virulence? a. Antibiotic therapy b. Inoculating an animal with the bacterium leading to its sickness (lab animals are usually used ) c. transferring onto fresh medium over and over d. Polymerase chain reaction (PCR)

b. Inoculating an animal with the bacterium leading to its sickness (lab animals are usually used )

In adaptive immunity, ________ are special compounds produced by cytotoxic T cells that cause apoptosis in target cell (a body cell infected with the virus or transformed into cancerous cell) by creating holes in the cytoplasmic membrane and digestion of the cell`s components. a. toxic oxygen species b. Perforins and Granzymes c. interleukins and cytokines d. Interferons

b. Perforins and Granzymes

In bacterial conjugation, formation of an Hfr strain of Ecoli sopmetimes happens. Hfr strains of Escherichia coli _________ a. have multiple separate plasmids including R and F plasmids b. have an F factor integrated into bacterial chromosome. c. have the F factor as a separate plasmid. d. do not possess an F facto

b. have an F factor integrated into bacterial chromosome.

What is NOT true about immunoglobulines? a. consists of constant and variable chains b. produced by pathogens. c. Immunoglobulins are produced by B cells d. also known as antibodies

b. produced by pathogens.

Staphylococcus aureus and Streptococcus pyogenes strains can produce ________ that cause(s) the severe and sometimes life-threatening symptoms of toxic shock syndrome. a. AB toxins b. superantigen toxins c. endotoxin d. cytolytic toxins

b. superantigen toxins

Genetically modified plants contain a _____, that makes the resistant to ______ a. Clostridium botulinum/glyphosate b. bacillus turengiensis (Bt) toxin gene / glyphosate c. Bacillus turengiensis (Bt ) toxin gene/being consumed by leaf-eating insects (pests) d. Clostridium tetani / any herbicide

c. Bacillus turengiensis (Bt ) toxin gene/being consumed by leaf-eating insects (pests)

In biotechnology, what is NOT a stage in a PCR reaction a. Denaturing ("melting") b. Primer extension c. Endonuclease cutting d. Primer annealing

c. Endonuclease cutting

In bacterial genetics, consider a mutation in which the base pair substitution happens from UAC to UAG. the UAC codons encode the amino acid tyrosine, the UAG is a stop codone. Which type of point mutation is this? a. Silent b. frameshit c. Nonsense d. missense

c. Nonsense

DiGeorge's syndrome is a developmental defect that prevents the maturation of the thymus. What cell type would be reduced by this condition? (hint: think what type of cells matures inside thymus)? a. neutrophiles b. Macrophages c. T cells d. B cells

c. T cells

Chemotaxis in bacteria occurs through the use of a. global control b. stringent response with production of alarmones c. a modified two-component system. d. quorum sensing.

c. a modified two-component system.

An Example of a chemical mutagens is _____ a. UV radiation b. ionizing radiation c. nitrogenous base analogs

c. nitrogenous base analogs

In microbial regulatory systems, the function of a kinase in conveying the signal is a. glycosylation b. response regulation. c. phosphorylation d. methylation

c. phosphorylation

When arginine is introduced to a culture already growing exponentially in a medium without arginine, what occurs? (think of inducible and repressible operons) a. Growth continues, production of enzymes for arginine synthesis increases 10 fold b. nothing happens c. All cellular growth stops d. Growth continues, but the production of enzymes required for the synthesis of arginine stops

d. Growth continues, but the production of enzymes required for the synthesis of arginine stops

Which of the following is NOT a common step in molecular cloning using plasmids? a. Insert the recombinant vector into a host b. Ligate DNA into vectors c. Cut DNA into a bunch of fragments uisng restriction endonucleases d. Hybridize DNA molecules using microarray

d. Hybridize DNA molecules using microarray

What is NOT correct about B cells a. Part of the adaptive immunity b. Carry immunoglobulin surface receptors c. Originate and mature in the bone marrow d. Need antigen to be presented to them by APCs (antigen presenting cells)

d. Need antigen to be presented to them by APCs (antigen presenting cells)

An ENDOGENOUS pyrogen is (hint: endogenous means coming from the "inside ") a. a fever-causing chemical secreted by bacteria that b. a chemical from the pathogen`s cell wall that causes fever c. bacterial fimbrae d. a chemical produced by a host own immune system that causes fever e. a bacterial capsule

d. a chemical produced by a host own immune system that causes fever

In innate immunity, oxygen compounds toxic to pathogens include a. nitric oxide. b. hypochlorous acid. c. hydrogen peroxide d. all of the above

d. all of the above

A mutant that has a nutritional requirement for growth (i .e., can not synthesize a specific aminoacid) is an example of a(n) a. organotroph b. heterotroph c. autotroph d. auxotroph

d. auxotroph

The ability of humans to resist a disease is called a. resistance b. syndrome c. dormancy d. immunity

d. immunity

phagocytes have a pathogen-recognition system known as ________ that leads to the recognition, containment, and destruction of a pathogen. a. pathogen-associated molecular pattern (PAMP) b. collagen c. fibrin d. toll-like receptors (TLRs) that belong to the group of pattern recognition receptors (PRR)

d. toll-like receptors (TLRs) that belong to the group of pattern recognition receptors (PRR)