Microbiology Lecture 3 Exam

Please select the INCORRECT statement regarding mutation. A missense mutation is also called a synonymous mutation, meaning no change in the amino acid encoded. A base substitution is a mutation in which the wrong nucleotide has been incorporated. A reversion is a mutation that corrects a defect caused by an earlier mutation. Spontaneous mutations are those that occur during the normal processes of a cell. Insertional inactivation is the disruption of a gene's function due to a DNA segment inserted into the gene.

A missense mutation is also called a synonymous mutation, meaning no change in the amino acid encoded.

What is the difference between a primary pathogen and an opportunistic pathogen? A primary pathogen is a microbe that is able to cause disease in an otherwise healthy individual, while an opportunistic pathogen is a microbe that causes disease only when introduced into an unusual location or into an immunocompromised host. A primary pathogen is an environmental microbe that is able to cause disease in an otherwise healthy individual, while an opportunistic pathogen is always a member of the normal microbiota and only causes disease in an immunocompromised host. An opportunistic pathogen is a microbe that is able to cause disease in an otherwise healthy individual, while a primary pathogen is a microbe that causes disease only when introduced into an unusual location or into an immunocompromised host. A primary pathogen is an environmental microbe that is able to cause disease in an otherwise healthy individual, while an opportunistic pathogen is always a member of the normal microbiota and causes disease only when introduced into an unusual location. A primary pathogen is a microbe that is able to cause disease in an otherwise healthy individual, while opportunistic pathogens are the microorganisms routinely found growing in and on the body of a healthy individual.

A primary pathogen is a microbe that is able to cause disease in an otherwise healthy individual, while an opportunistic pathogen is a microbe that causes disease only when introduced into an unusual location or into an immunocompromised host.

The composition of the normal microbiota may be affected by A. hormonal changes. B. use of antibiotics. C. obesity level. D. diet. E. All of the answer choices are correct.

A. hormonal changes. B. use of antibiotics. C. obesity level. D. diet.

which base pairing is incorrect A:G C:G T:A A:T G:C

A:G

Colonization of the body is inhibited by A)the shedding of skin cells. B)the movement of mucus by cilia. C)peristalsis in the digestive tract. D)the flushing action of the urinary tract. E)All of the answer choices are correct.

All of the answer choices are correct.

Select the INCORRECT definition regarding the progression of an infectious disease. Illness phase—period of time during which symptoms and signs of disease occur. Period of convalescence—period of recuperation and recovery from an illness. Incubation period—interval between the entrance of a pathogen into a susceptible host and the onset of illness caused by that pathogen. Carrier phase—period in which a pathogen is harbored without noticeable ill effects, but may be transmitted to other hosts. Prodromal period—a period of early, vague symptoms indicating the onset of a disease.

Carrier phase—period in which a pathogen is harbored without noticeable ill effects, but may be transmitted to other hosts.

How many nucleotides are in a codon? 3 1 5 2 4

3

If a disease affects only a human and not an animal, then it would be difficult to fulfill Koch's postulate number 3 2 1 5 4

3

what is the complementary sequence of 5' AGGCUAAC 3'

3' TCCGATTG 5'

in which direction does the ribosome move along RNA?

5' to 3'

Which of the following is NOT a mechanism for avoiding destruction by a phagocyte? These are all mechanisms for avoiding phagocytic destruction. Some pathogens prevent phagosome-lysosome fusion. Some pathogens escape from the phagosome before it fuses with lysosomes. Some microbes can survive the destructive environment within the phagolysosome. Some microbes produce IgA protease that cleaves IgA, the class of antibody found in mucus and other secretions.

Some microbes produce IgA protease that cleaves IgA, the class of antibody found in mucus and other secretions.

You mix two bacterial stains in a tube of glucose-salts agar. One strain is His−, Val−, while the other strain is Trp−, Leu−. You previously showed that neither strain grows on glucose-salts agar. After incubating the tube, you plate a sample onto a new glucose-salts agar plate. Several colonies grow. What do you know is TRUE about these colonies?

The bacteria in the colonies are His+, Val+, Trp+, Leu+

A number of viruses often include a similar set of symptoms when they cause an infectious disease state (fever, headache, fatigue, runny nose). Why would they all cause the same symptoms if they're different viruses? All animal viruses must attach to and enter host cells. Since this step in the life cycle is identical in all viruses, the signs and symptoms that follow will also be identical. The symptoms are associated with the immune system's response, NOT the molecules from the pathogens themselves. Our responses against viruses are fairly similar, regardless of virus type, so the symptoms are similar. They all possess the same basic virulence genes and molecules, so they all trigger the same responses. Viruses specifically infect mainly epithelial membranes. As such, the virally induced reaction is similar in different areas of the body due to the same basic cell types (epithelial cells) being infected in each area. Most viruses infect the upper respiratory tract. This leads to the common set of symptoms listed above. Only a few viruses infect areas away from this region.

The symptoms are associated with the immune system's response, NOT the molecules from the pathogens themselves. Our responses against viruses are fairly similar, regardless of virus type, so the symptoms are similar.

Which of the following is NOT a method by which pathogens penetrate a mucous membrane? By directing uptake by non-phagocytic cells. These are all methods used by pathogens to penetrate mucous membranes. By directing/ enhancing uptake by macrophages. Via M cells in the antigen-sampling process. Through a bite wound or knife cut.

Through a bite wound or knife cut.

Adenine binds to?

Thymine (T) or Uracil (U)

Which statement applies to endotoxins? A-B toxins are composed of an active subunit (A subunit) and a binding subunit (B subunit). Membrane-damaging toxins include pore-forming toxins and phopholipases. The immune system produces neutralizing antibodies against them. Toxin is part of the outer cell membrane and has no effect unless released. Superantigens stimulate T-Helper cells, resulting in a cytokine storm.

Toxin is part of the outer cell membrane and has no effect unless released.

Which of the following statements is CORRECT regarding transformation? DNA is transferred from one bacterial cell to another by means of a bacteriophage. Transformation is the uptake of "naked" DNA from the environment. Transformation involves the formation of a sex pilus through which plasmid DNA is shared between bacteria. Transformation depends on a donor cell containing an F plasmid and a recipient cell that does not. Transformation is a process that depends on physical contact between two bacterial cells.

Transformation is the uptake of "naked" DNA from the environment.

Would an antibody response against the B subunit of an A-B toxin protect against the effects of the toxin? A. Yes. If antibodies bind to the B portion, the toxin can no longer bind to target cells and will thus not affect those cells. B. No. Even if antibodies bind to the B portion of the toxin, it is the A portion that actually causes damage to the cell. C. Yes. If antibodies bind to the B portion, that portion of the toxin does not become activated, and thus does not damage the host cell. D. No. Even if antibodies bind to the B portion of the toxin, the toxin is still taken into the host cell by phagocytosis, damaging that cell. E. This question cannot be answered. The immune system does not mount a strong response against proteins, so this situation is unlikely to occur.

Yes. If antibodies bind to the B portion, the toxin can no longer bind to target cells and will thus not affect those cells

operons in bacteria can be describes as a group of genes that are controlled in a coordinated manner AND involve monocistronic DNA. a group of genes that are controlled in a coordinated manner AND involve polycistronic DNA. a group of genes that are controlled in a coordinated manner AND involve polycistronic mRNA. a group of genes that are controlled in a coordinated manner AND involve both monocistronic and polycistronic DNA. a group of genes that are controlled in a coordinated manner AND involve monocistronic mRNA.

a group of genes that are controlled in a coordinated manner AND involve polycistronic mRNA.

Which of the following would be considered a sign of a disease? A. Severe headache B. Throbbing pain C. Intense nausea D. A rash E. All of the choices are signs of a disease.

a rash

What is C5a peptidase? an enzyme produced by the host cell in response to infection a virulence factor an enzyme that synthesis C5a a molecule promoting chemotaxis an enzyme that degrades IgA

a virulence factor

activators are allosteric proteins AND are involved in positive control . are allosteric proteins AND are involved in negative control. are involved in negative control AND bind to the terminator. are involved in negative control AND bind to the start codon. are involved in positive control AND bind to the terminator.

are allosteric proteins AND are involved in positive control

the first step in the establishment of infection is that the organism must A) invade host tissues. B) attach to host cells. C) evade phagocytes. D) produce toxins. E) cause apoptosis.

attach to host cells

Chemical mutagens that mimic the naturally occurring bases are called nitrogen mustards nitrous oxide nucleobase copiers base analogs alkylating agents

base analogs

what is true about DNA replication it is bidirectional. It starts at an origin of replication. It requires RNA primers. All of the choices are correct. It is semiconservative.

bidirectional starts at an origin of replication requires RNA primers semiconservative

Which of the following does the pathogenic strain of Streptococcus pneumoniae use to survive in the host? pili plasmids flagella spike protein capsule

capsule

People who carry and may spread pathogenic organisms without any apparent signs or symptoms of illness are called secondary infectors primary infectors carriers opportunists mutualists

carriers

An example of genetic variation used in pathogen survival may be surviving within a phagocyte avoid the killing effects of complement system proteins protease production changing the pilus antigens preventing encounters with phagocytes

changing the pilus antigens

a stop codon enhances the binding of the e-polymerase. codes for no amino acid. codes for the stop amino acid AUG codes for the stop amino acid s-methyl-methionine. forms a hairpin loop forcing the ribosome to fall off.

codes for no amino acid

A relationship in which one partner benefits and the other is unaffected is termed independence parasitism dysbiosis commensalism mutualism

commensalism

The placement of the amino acid during translation is determined by the antiparallel nature of mRNA. secondary structure of the newly forming protein. DNase, which transcribes both molecules. sequence of nucleotides at the 5' end of the tRNA. complementarity of the codon-anticodon.

complementarity of the codon-anticodon.

Gene transfer that requires cell-to-cell contact is transformation competency conjugation transduction homologous recombination

conjugation

in conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA from any source. from any species of bacteria. from the same species of bacteria. only through plasmids. from any source AND only through plasmids.

from the same species of bacteria

which statement describes the 3' end of DNA? has a hydroxyl group attached to the number 3 carbon of deoxyribose. has a hydroxyl group attached to the number 3 carbon of ribose. always has thymine and uracil attached to it. attaches to the 3' phosphate group of the incoming nucleotide. usually has guanine and guanine attached to it.

has a hydroxyl group attached to the number 3 carbon of deoxyribose.

The period of time between exposure to an agent and the onset of disease signs and symptoms is called the prodromal phase carrier phase decline phase lag phase incubation phase

incubation phase

membrane ruffling is is induced by some bacteria that trigger increased synthesis of a cell's actin, leading to expulsion of those bacteria. is induced by some host cells that trigger rearrangements of their actin, leading to engulfment of some bacteria. is induced by some bacteria that trigger rearrangements of a cell's actin, leading to engulfment of those bacteria. is induced by some bacteria that trigger rearrangements of a cell's myosin, leading to pinocytosis of those bacteria. is induced by some bacteria that trigger breakdown of a cell's actin, leading to exocytosis of those bacteria.

induced by some bacteria that trigger rearrangements of a cell's actin, leading to engulfment of those bacteria.

The number of organisms necessary to cause infection is termed the A. infectious dose. B. fatal number. C. minimum lethal dose. D. pathogenic number. E. incidence number.

infectious dose

Some segments of the precursor mRNA in eukaryotes are non-coding and are called exons uselessans integrans introns genes

introns

Adhesins are often found at the tip of pili AND are endotoxins. involved in the first step of the infectious process AND are endotoxins. involved in the first step of the infectious process AND are often found at the tip of pili. exotoxins AND are involved in the first step of the infectious process. are exotoxins OR are endotoxins.

involved in the first step of the infectious process AND are often found at the tip of pili.

In the lac operon, glucose is preferentially used over sucrose in E. coli as a result of catabolite repression AND levels are correlated with cAMP levels. is preferentially used over sucrose in E. coli as a result of catabolite repression AND levels are directly sensed via catabolite repression. is preferentially used over lactose in E. coli as a result of catabolite repression AND levels are correlated with cAMP levels. is preferentially used over lactose in E. coli as a result of catabolite repression AND glucose levels are the inverse of cAMP levels. is preferentially used over lactose in E. coli as a result of catabolite repression AND levels directly affect the production of lactose dehydrogenase.

is preferentially used over lactose in E. coli as a result of catabolite repression AND glucose levels are the inverse of cAMP levels.

the E-site is responsible for the release of the tRNA. is the aminoacyl site on the ribosome. is found on the RNA polymerase enzyme. is found on the 35S polysome. is another name for anticodon.

is responsible for the release of the tRNA.

the P-site is an allosteric site AND is a promoter site. is the peptidyl site on the ribosome. is a promoter site on the ribosome. is found on the polymerase enzyme. is an allosteric site on an enzyme.

is the peptidyl site on the ribosome.

which is true about prokaryotic (bacterial) RNA polymerase? requires a primer reads template in 5' - 3' direction has a detachable subunit, alpha factor, which recognizes the promoter it is used during transcription all of the above

it is used during transcription

The "hygiene hypothesis" proposes that A. lack of exposure to microbes can lead to development of allergies. B. good hygiene always prevents development of disease. C. hand washing is the best preventative measure against infection. D. the immune system develops best in a clean environment. E. adaptive immunity only develops in a sterile environment.

lack of exposure to microbes can lead to development of allergies.

The chemical nature of endotoxins is that of a/an A)protein. B)lipopolysaccharide. C)nucleic acid. D)amino acid .E)carbohydrate.

lipopolysaccharide

What is the term used for the modern equivalent to Koch's postulates? Atomic Theory Molecular Postulates Pasteur's Systematics Protein Theory Hoch's Postulates

molecular postulates

the symbiotic relationship wherein both partners benefit is termed A. commensalism. B. parasitism. C. independence. D. mutualism. E. dysbiosis.

mutalism

The source of variation among microorganisms that were once identical is mutation virulence factors activators antibiotic resistance sigma factors

mutation

The microorganisms that are regularly found in or on the body, yet do no apparent harm are called A. abnormal microbiota. B. Normal (resident) microbiota. C. transient microbiota. D. variant microbiota. E. random biota.

normal (resident) microbiota

What is the site called on DNA to which the repressor protein binds? regulon promoter operator repressor operon

operator

The characteristics displayed by an organism in any given environment is its archaetype phenogene mutatotype phenotype genotype

phenotype

Colonies of the bacterium Serratia marcescens are red when incubated at 22°C but white when incubated at 37°C. This is an example of antigenic variation selective medium mutation phenotypic change genotypic change

phenotypic change

Bacteria may survive phagocytosis by A) preventing fusion of the lysosome with the phagosome AND mimicking host molecules. B) avoiding recognition and attachment of lymphocytes AND lysing the phagosome. C) lysing the phagosome AND mimicking host molecules .D) preventing encounters with phagocytes AND preventing fusion of two phagosomes. E) preventing fusion of the lysosome with the phagosome AND lysing the phagosome.

preventing fusion of the lysosome with the phagosome AND lysing the phagosome.

The chemical nature of exotoxins is that of a A)protein. B)carbohydrate. C)lipid. D)lipopolysaccharide. E)carbohydrate.

protein

RNA is characterized by which one of the following features? double stranded deoxyribose ribose thymine all of the above

ribose

Which of the following would NOT be considered virulence factor(s)?

ribosomes

The F plasmid carries the information for the sex pilus recipient cell DNA antibiotic resistance the Y chromosome bacterial flagella

sex pilus

which molecule carries an anticodon? 50S ribosome mRNA tRNA rRNA 30S ribosome

tRNA

Irradiation of cells with ultraviolet light may cause four nucleotides to covalently bind together. thymine dimers. cytosine trimers. the addition of uracil. adenine complementary base pairing with cytosine.

thymine dimers

the mechanism by which genes are transferred into bacteria via viruses is called ellipsis transduction transformation conjugation replica plating

transduction

The microorganisms that are occasionally found in or on the body are called transient microbiota normal microbiota random microbiota abnormal microbiota variant microbiota

transient microbiota

Segments of DNA capable of moving from one area in the DNA to another are called inverted repeats mutagens transposons intercalating agents base analogs

transposons

Attributes of an organism that promote pathogenicity are called A. disease factors. B. colonization factors. C. virulence factors. D. mutualistic factors. E. pathogenic factors.

virulence factors

Which of the following could be the result of an enterotoxin? A) Vomiting and diarrhea B) Inability to contract muscles C) Inability to relax muscles D) Accumulation of respiratory secretions E) Separation of dermis and epidermis

vomiting & diarrhea

Newborn babies acquire microbiota A. when passing through the birth canal. B. through breastfeeding. C. by contact with the mother's skin. D. from the environment. E. All of the above are a source of microbiota.

when passing through the birth canal through breastfeeding by contact with the mother's skin from the environment

In order for insertional inactivation to occur, the transposon must be placed randomly in the genome. within the gene in question. upstream from the gene in question. downstream from the gene in question. in an intron.

within the gene in question

The material responsible for transformation was shown to be DNA by Watson and Crick. Avery, MacLeod, and McCarty. Lederberg. Stanley. Beadle and Tatum.

Avery, MacLeod, and McCarty

The report that genes direct the synthesis of proteins was first made by Beadle and Tatum Lederberg Mendel Watson and Crick Curie

Beadle & Tatum

Home-canned foods should be boiled before consumption to prevent botulism. Considering that this treatment does NOT destroy endospores, why would it be helpful in preventing the disease? Because the heat would denature the botulism exotoxin and inactivate it. The exotoxin is what leads to the disease symptoms, so this would make the food safer. Because the heat would denature the botulism endotoxin and inactivate it. The endotoxin is what leads to the disease symptoms, so this would make the food safer. Because it would destroy the vegetative cells, and only the vegetative cells cause the disease. Because it would at least weaken the endospores, making them more susceptible to elimination by our immune system. Because although botulism exotoxin is harmless, it has a bad odor and boiling removes this, making the food more appealing to eat.

Because the heat would denature the botulism exotoxin and inactivate it. The exotoxin is what leads to the disease symptoms, so this would make the food safer.

Guanine bind to?

Cytosine (C)

Please select the CORRECT definition regarding interactions between hosts and microbes. Dysbiosis—an imbalance in the microbiome that may be caused by taking antimicrobial medications. Fc receptors—molecule that binds the antigen-binding region of an antibody. Immunocompetent—having a weakness or defect in the innate or adaptive defenses. Parasitism—relationship between two organisms in which one partner benefits and the other is unaffected. Secondary infection—infection in a previously healthy person, such as measles in a child who has not had measles before.

Dysbiosis—an imbalance in the microbiome that may be caused by taking antimicrobial medications.

Which of the following is an example of damage caused by inflammation? A) Glomerulonephritis - resulting from activation of complement system proteins. B) Ectopic pregnancy - resulting from fallopian tube scarring caused by cross-reactive antibodies. C) Meningitis - caused by presence of immune complexes in the membranes surrounding the brain. D) Acute rheumatic fever - resulting from damaging enzymes and toxic products released by phagocytes. E) Acute rheumatic fever - caused by scarring of the heart tissue following complement activation.

Glomerulonephritis - resulting from activation of complement system proteins.

Why is it beneficial for a bacterial cell to be able to use glucose FIRST as an energy source (until it is depleted), THEN switch to lactose? For conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown AND because lactose always triggers endospore formation, which may be unnecessary. Glucose is an easier compound to break down and obtain energy from than lactose AND for conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown? Glucose provides 10x as much energy when broken down as lactose AND for conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown? For conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown AND because breakdown of lactose produces inhibitory compounds. Lactose can only be used by a small number of bacteria as an energy source AND for conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?

Glucose is an easier compound to break down and obtain energy from than lactose AND for conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?

Two bacterial genes are transduced simultaneously. What does this suggest about their proximity to each other within the original host genome? Nothing. It's highly likely that two separate virus particles were carrying each gene, and that they coinfected the new target cell at the same time. This could mean the two original genes might not even be from the same original host cell! It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously. They must be within five gene lengths of each other, but not necessarily immediately adjacent. If they were immediately adjacent, the transposons that facilitate the transfer of genetic information between the two cells wouldn't be able to "jump" into them. It doesn't mean anything. Transduction relies on the ability of a cell to take up foreign DNA. It's possible here that the cell has simply taken up two separate bits of DNA at the same time from the surrounding environment. It's highly likely that one gene was on the chromosome but the other was actually on a plasmid; if those two elements are in one cell, genes can be transferred simultaneously.

It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously.

The connection between a particular organism and a specific disease was first made by A. Jenner. B. Pasteur. C. Koch. D. van Leeuwenhoek. E. Hooke.

Koch

The series of steps used to connect an organism to a disease are known as A. Pasteur's postulates. B. Lister's aseptics. C. Linnaeus' taxonomics. D. Koch's postulates. E. Bergey's manual

Koch's postulates

Which of the following members of the normal microbiota inhibit the growth of Candida albicans? E. coli Neisseria species Propionibacterium species Staphylococcus species Lactobacillus species

Lactobacillus species

Which of the following is/are true about endotoxins? The toxic effects depend on the bacteria from which it came. Lipid A is the toxic portion of the molecule. The lipid A portion is heat sensitive. The toxic effects depend on the bacteria from which it came AND they are proteins. They are proteins.

Lipid A is the toxic portion of the molecule

The amino acid that is placed first during translation in bacteria, mitochondria, and chloroplasts is glycine the promoter N-formyl-glycine methionine N-formyl-methionine

N-formyl-methionine

When E. coli is placed in a medium containing both glucose and lactose, why does cell growth stop temporarily when the glucose is used up? Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time. Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon—it can only do this if the culture medium is placed in the dark at 22oC. The presence of glucose denatures the lactose in the medium; once the glucose is depleted, the lactose has to regain its original shape before the cells can use it. Glucose is the preferred medium of the cells—when it is available, they grow extremely fast, and this depletes all the energy in the cell which must be replaced before it can use lactose. Once lactose is depleted, the cell must use the glucose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time.

Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time.

You have three patients: patient A has a deep cut on his arm, while patient B is complaining of diarrhea. Patient B is a smoker. Patient C has a respiratory viral infection. Pick the CORRECT statement regarding the risk of patients A and B to acquiring the respiratory virus from patient C. Patient B is more at risk - being a smoker compromises the mucociliary escalator which protects the respiratory system. Patient B is less at risk - being a smoker toughens up the mucociliary escalator, protecting the respiratory system. Neither patient A nor patient B is at risk; we all have a mucociliary escalator that completely protects the respiratory tract. Patients A and B are at equal risk - they both have other health issues which increase their susceptibility to respiratory viruses. Patient A is at most risk - the person's first line of defense (skin) has been compromised by the injury.

Patient B is more at risk - being a smoker compromises the mucociliary escalator which protects the respiratory system.

Which person is LEAST at risk of acquiring a pathogen via the skin? Veterinarian handling a feral cat. Person getting a body piercing. Person getting a tattoo. Person bitten by a mosquito. Person taking a recreational run.

Person taking a recreational run.

In order to colonize a host, a pathogen has to deal with the host's defenses. Which of the following is NOT a mechanism for doing this? Rapid turnover of pili to shed bound antibodies. Production of IgA proteases for cleaving IgA. Producing lactoferrins for binding iron. Antigenic variation by changing surface molecules. Production of siderophores for binding iron.

Producing lactoferrins for binding iron.

Which is true about superantigens? A) They are a type of exotoxin AND they stimulate an abnormally high number of TC cells. B) They bind to MHC class II molecules on T cells AND they are a type of endotoxin. C) They bind to MHC class II molecules on T cells AND they enhance specific antibody production. D) They are processed intracellularly AND they are a type of endotoxin. E) They are a type of exotoxin AND they stimulate an abnormally high number of TH cells.

They are a type of exotoxin AND they stimulate an abnormally high number of TH cells

How do activators facilitate transcription? They bind to DNA, thereby making it easier for RNA polymerase to initiate translation. They bind to DNA, thereby making it easier for RNA polymerase to initiate transcription. They bind to RNA, thereby making it easier for DNA polymerase to initiate transcription. They bind to DNA, thereby making it easier for DNA polymerase to initiate transcription. They bind to RNA, thereby making it easier for RNA polymerase to initiate translation.

They bind to DNA, thereby making it easier for RNA polymerase to initiate transcription.

which of the following WOULD be considered virulence factors?

adhesins capsules endotoxins proteases

In conjugation the donor cell is recognized by the presence of an F plasmid a Y chromosome diploid chromosomes an SOS response nucleus

an F plasmid

competent cells are able to take up viral DNA AND can be created in the laboratory are able to take up naked DNA, can occur naturally, AND can be created in the laboratory. are always antibiotic resistant, are always auxotrophs, AND occur naturally. can be made in the laboratory, are always antibiotic resistant, AND are always auxotrophs. are able to take up naked DNA, ALWAYS occur naturally, AND are always antibiotic resistant.

are able to take up naked DNA, can occur naturally, AND can be created in the laboratory