Microbiology BIOL 2420 : Chapter 13, 14, 15
When a cell's cytoplasmic PRRs detect viral RNA, the cell responds by synthesizing and secreting a(n) ______.
interferon
________ , a type of cell specialized for phagocytosis, need the assistance of helper T-cells to become fully activated, showing an example of the cooperation between the innate and adaptive response systems.
macrophages
When microbes enter through a minor skin wound, resident ______ in the tissues destroy them. If these microbes are not rapidly cleared, the resident cells secrete _______ to recruit _______ for extra help.
macrophages; cytokines; neutrophils
Outside of living cells, viruses are _______.
metabolically inert
Naked viruses do not have an outer lipid bilayer. These viruses are called _______________-_____________ viruses.
non-enveloped
In ______-strand RNA viral genomes, the genome functions as an mRNA molecule
( + )
Of the single-stranded RNA viruses, some types have a ______ genome, which also serves as mRNA.
( + ) strand
Viruses that specifically target and kill cancer cells are called ______ viruses.
oncolytic
The best analogy for the macrophages' role is that of ______.
police officers who routinely protect city streets
An infectious agent that consists of protein and no nucleic acid is called a(n)
prions
Mad cow disease and chronic wasting disease are caused by infectious agents called
prions
The stage of viral multiplication at which budding occurs is ______.
release
The viral proteins that stick out from either the lipid bilayer of enveloped viruses or the capsid of non-enveloped viruses, and attach to host cells, are ______.
spikes
The pattern recognition receptors (PRRs) of an innate immunity cell allow that cell to tailor its response according to the general category of pathogen by determining ______.
the assortment of the pathogen's MAMPs
The first-line defenses of innate immunity are ______.
the body's borders
A phagocyte binds directly to a bacterial cell when ______.
the cell's receptors bind to mannose on the bacteria
Indirect binding of a phagocyte to a bacterial cell occurs when ______.
the cell's receptors first bind to opsonins that have coated the bacterial cell
Opsonization resulting from the complement cascade is ______.
the coating of a microbial cell surface with opsonins, in this case, C3b
B cells
Antibody response
During the _______ or maturation step in viral multiplication, capsids and genetic material are packaged into virions.
Assembly
Antibodies are produced by effector forms of ______.
B cells
True or false: There is no need to classify viruses because they are not living organisms.
False ; Although viruses are not living, classification is still important for identification and study.
Human cells are larger than viruses by which size factor?
Human cells are approximately 1 THOUSAND times larger than viruses.
In adaptive immunity, exogenous antigens are presented on _______ molecules and are recognized by _______ cells.
MHC class II; helper T
In animals, replication of most DNA viruses occurs within the host cell's
NUCLEUS
The smallest virus is approximately 10 ______ in diameter.
Nanometers
________ are also called polys, polymorphonuclear leukocytes, or PMNs.
Neutrophils
_______ means coating a microbial surface with proteins or other molecules, making it easier for it to be engulfed by a phagocytic cell.
Opsonization
What is the main role of neutrophils?
Phagocytosis
Replicases are ______ polymerases.
RNA-dependent RNA
Viruses that have an RNA genome and use reverse transcriptase to synthesize a DNA copy of that genome are called ______.
Retroviruses
Which of the following are diseases caused by prions?
Scrapie Creutzfeldt-Jakob disease Bovine spongiform encephalopathy
What are possible outcomes of a ligand binding to its receptor on a cell's surface?
The internal portion of the receptor becomes modified. A response is triggered in the cell, initiating some change.
Which of the following statements about viruses are true?
The viral capsid is composed of protein. Viruses contain RNA or DNA but not both.
Which descriptions are true for neutrophils but not macrophages?
They have more killing power. They release granule contents and DNA strands to entrap and destroy microbes
Which of the following processes are required for production of virus particles in a host cell?
Translation of viral genes Replication of viral genome Transcription of viral genes
Infections that have a sudden onset of symptoms of relatively short duration are described as
acute infections
The humoral immune response is delivered by ______.
antibodies
The receptor on the surface of B cells is most similar to a(n) ______.
antibody molecule
The main function of the lymphatic system is to allow ______ to interact with and activate lymphocytes.
antigens
B cells with anti-self B-cell receptors (BCRs) undergoing negative selection in the bone marrow are induced to undergo ____
apoptosis
Cytotoxic T cells (Tc cells) induce ______ in infected self cells and cancerous cells.
apoptosis
Adhesion molecules can be thought of as the ______ of the cell, allowing, for example, endothelial cells lining blood vessels to bind passing phagocytic cells.
hands
What is the lifespan of macrophages?
weeks to months
The alternative complement pathway is triggered ______.
when C3b binds to foreign cell surfaces to start the complement cascade
The major categories of animal viral infections are _______ infections, characterized by the sudden onset of symptoms of a relatively short duration, and _______ infections that can continue with or without symptoms for years.
Blank 1: acute Blank 2: persistent
_______ is an activated complement molecule that can serve as a strong chemoattractant for phagocytic cells.
C5a
The process in which leukocytes squeeze between the endothelial cells to enter infected or inflamed tissues is referred to as ______
DIAPEDESIS
Which of the following about classifying viruses is FALSE?
It is not as important as classifying organisms since they are not living entities.
Which facts best support the position that viruses are not living organisms?
Viruses are inert outside of a host. Viruses cannot reproduce on their own.
Infectious agents that have a simpler structure than viruses include ______.
both viroids and prions
The lymphatic system's primary role is to _______.
bring antigens into contact with lymphocytes, allowing activation, proliferation, and differentiation of specific B and T cells into effector cells
This micrograph shows viruses being released from an infected cell by the process of
budding
Which of the following viral release methods may not initially destroy the cell?
budding
Antibody-antigen binding can activate the complement cascade via the ______.
classical pathway
During inflammation, ________ system proteins leak out into tissues to become cleaved and activated and attack microbes.
complement
Opsonization, inflammatory response, and lysis of foreign cells are three protective outcomes of the ______.
complement system
Viral genomes can be ______.
either single-stranded or double-stranded
Macrophages are scavengers. As such, not only do they engulf and destroy foreign invaders, but they also ______.
engulf and recycle dead cells and debris
Dendritic cells provide a link between the innate and adaptive immune systems by ______.
engulfing material and degrading it, then presenting it to the adaptive system cells
The phospholipid bilayer found surrounding the capsid of some viruses is the ______.
envelope
In the case of animal viruses, the molecules that viral spikes attach to on the host cell in order to gain entry are typically ______.
glycoproteins
A ___________ is any type of white blood cell with noticeable cytoplasmic granules.
granulocyte
One of the traits of IgG molecules that gives them such a strong capacity for protective responses is their long _____ -life of 21 days.
half
Adhesion molecules can be thought of as the ______ of the cell, allowing, for example, endothelial cells lining blood vessels to bind passing phagocytic cells
hands
The two main categories of T lymphocytes necessary to mount a response against foreign pathogens are cytotoxic T cells and _____ T cells.
helper
Humoral immunity defends against ______.
invaders that are not within the cell
A B cell in a lymph node is a(n) ______ type of lymphocyte, while a plasma cell is a fully ______ lymphocyte.
mature but naive; differentiated
_____ B cells are long-lived and allow for a much faster response if the same antigen is encountered at a later date.
memory
Without lymphocytes, we wouldn't be able to ______.
mount an adaptive immune response
An antigen interacting with a T-cell receptor ______.
must be broken down into peptide fragments and presented on an MHC molecule
Classifying viruses
- Viruses can be classified based on different viral characteristics. - An online database classifying viruses is kept by the ICTV (International Committee on Taxonomy of Viruses). - It provides a useful way to identify and study viruses.
T cells
Interact with target cells and then cause changes in those cells
The secondary response is much faster and more effective than the primary response because of the presence of ______ lymphocytes left over from the primary response.
Memory
Before a B cell undergoing antigen-induced activation can proliferate, it must usually get help from ______.
another type of lymphocyte--a helper T cell (TH).
Y-shaped proteins that bind to specific antigens are called
antibodies
The presence of ______ can initiate the classical pathway of complement activation.
antibodies bound to antigen
The term "Fab region" stands for "fragment of ______ binding region."
antigen
Cells that produce MHC class II molecules are collectively referred to as ______.
antigen-presenting cells
Unlike B and T cells, NK cells ______.
do not have antigen specific receptors
The exposed surfaces of the body are lined by ______ cells.
epithelial
A molecule that can bind to a given surface receptor is called a ______ for that receptor.
ligand
In humans and other animals, sacrificing "self" cells may ______.
limit the spread of an infection eliminate cells no longer needed
Enveloped viruses have an outer layer made up of _______.
lipid
A _____________ cell provides the second signal confirming that an antigen-activated B cell needs to start proliferation and differentiation into a plasma cell.
lymphocyte
The primary cellular participants in the adaptive immune responses are
lymphocytes
________ which include B cells and T cells, are the primary cell type involved in the adaptive immune responses.
lymphocytes
Differentiated B lymphocytes that produce antibodies are called _______ cells.
plasma
DNA viruses often encode their own DNA _________ for DNA synthesis, which allows them to replicate even if the host cell is not actively duplicating its own chromosome.
polymerase
The complement system is a series of ______ that circulate in the ______.
proteins; blood and extracellular fluid
(+) strand genome
serves as mRNA
The four basic functions of inflammation include all of the following EXCEPT ______.
recruitment of the full spectrum of adaptive immune responses to the area
When a phagocyte encounters something too large to engulf, it will ______.
release its toxic contents into the surrounding area as a means to degrade the particle
In addition to phagocytosis, neutrophils kill microbes by ______.
releasing destructive enzymes
The primary end outcome of activation of the complement system is ______.
removal and destruction of invading microbes
The replication strategies of animal viruses can be divided into three general categories: those used by ______ viruses, _____ viruses, and reverse transcribing viruses.
DNA RNA
Attachment of animal viruses to the host cell typically occurs by means of ______.
spikes
____ is the primary immunoglobulin secreted into the mucous membranes of the gastrointestinal and respiratory tracts.
IgA
Humoral immunity is mediated by five classes of immunoglobulins: IgA, ______ ,_______ ,_______ , and _____
IgD IgE IgG IgM
The human immune system produces five main classes of antibodies. What are they?
IgD IgG IgE IgM IgA
Newborns are protected by maternal _____ , which is present in the first breast milk, also called colostrum.
IgG
The maternal immunoglobulin that protects the fetus and newborn is .
IgG
The maternal immunoglobulin that protects the fetus and newborn is ___
IgG
Which protective maternal antibody is present in colostrum?
IgG
A pathogen that is able to avoid fusion of lysosomes with phagosomes can ______.
avoid destruction by phagocytes
Plasma cells are effector ______ that produce _______.
B cells; antibodies
Oncoviruses are viruses that can ______.
cause cancer in humans
Chemicals that are secreted by certain cells of the immune system and which act at low concentrations to cause effects on other cells, are known as ______
cytokines
Specifically, interferons are ______.
cytokines that can induce antiviral effects
Most host cells have PRRs in their _______ , allowing the cells to screen their own internal contents for signs of invasion.
cytoplasm
When an enveloped virus gains entry to an animal cell by fusion, the virus envelope fuses with the ______.
cytoplasmic membrane
_____________ cells, a type of antigen-presenting cell, are responsible for initial activation of naive T lymphocytes in lymph nodes during a cell-mediated immune response.
dendritic
A particular type of cell from the innate immune responses is critical for initial T cell activation in lymph nodes. This cell is the ______.
dendritic cell
Which types of viruses are released by budding?
enveloped viruses
Viruses are best described as _______.
infectious agents
Natural killer cells belong to the group of lymphocytes called ______.
innate lymphoid cells
(-) strand genome
is the complement to mRNA
IgM ______.
is the first class of antibody produced during a primary response to an antigen
The parameters illustrated in this figure best describe a(n) ______ infection.
latent
If macrophages cannot rapidly clear invading microbes, those phagocytic cells produce cytokines that ______.
recruit neutrophils
Protection against intestinal pathogens in newborns might be provided by ______.
secretory IgA in the intestines provided by the newborn ingesting maternal breast milk
Reassortment of gene segments that encode viral surface proteins recognized by the immune system can result in a loss of the immune system's ability to recognize and respond to the virus. This phenomenon is called ________ antigenic .
shift
When comparing two different antibody molecules that bind to different epitopes, the amino acid sequence in the _______ region of each molecule will be different.
variable or Fab
Which one of the following items would not be a chemoattractant for phagocytic cells?
C3b
Which of the following are the three general shapes of most viruses?
Complex Helical Icosahedral
Double-stranded genome
Consists of both (+) and (-) strand
Viruses that can cause cancer in humans are known as ________viruses.
Oncogenic, oncoviruses, or onco
Microbes that have been opsonized are easier to engulf because phagocytes have __________ for opsonin proteins such as C3b on their surface.
RECEPTORS
The enzyme of RNA viruses that typically lacks proofreading ability and thus makes many mistakes compared to the polymerases of DNA viruses is ______.
REPLICASE
Which type of antigen is most common?
T-dependent
The function of the two arms of the Y-shaped antibody molecule is to ______.
bind to epitopes, or antigenic determinants
The process by which a virus is taken up by a host cell as a result of the host cell's cytoplasmic membrane surrounding the virion to form a vesicle is called ______
endocytosis
With respect to the body's borders, the contents of the digestive tract are ______.
outside the body
________ infections remain for years, or even the lifetime of the host, sometimes without any symptoms.
persistent
RNA viruses have a higher mutation rate than DNA viruses because replicases typically lack _______ ability.
proofreading
Many animal viruses have proteins called ____________ that attach to receptors on host cells.
spikes
Cytokines are analogous to the ______ of a cell.
voice
Reverse transcriptase is a(n) ______ polymerase.
RNA-dependent DNA
Which of the following carries out cell-mediated immunity?
T cells
A _______ is a single virus particle.
Virion
The accumulation of mutations in genes that encode viral surface proteins recognized by the immune system results in a type of antigenic variation called ______.
antigenic drift
When two different strains of a segmented virus enter the same cell, reassortment of the gene segments can occur, resulting in ______.
antigenic shift
Tumors are abnormal growths that result from a malfunction in the regulation of ______.
cell growth
The process of antibody- ______ cellular cytotoxicity (ADCC) relies on IgG antibodies binding targets, allowing NK cells to bind to their exposed Fc regions.
dependent
A negative consequence of inflammation can result when ______ and toxic products from ______ are inevitably released, damaging our own tissues.
enzymes; phagocytes
Innate immunity includes _______
first-line defenses effector actions sensor systems
The major classes of immunoglobulin molecules correspond to the _______.
five general types of constant regions.
The replication scheme of double-stranded DNA viruses ______.
follows the central dogma of molecular biology
PRRs in a cell's cytoplasm enable the cell to monitor ______ for signs of invasion.
its own internal contents
TLRs (toll-like receptors) in endosomes and phagosomes detect ______.
nucleotide sequences that are relatively common in bacterial DNA long molecules of double-stranded RNA
Toll-like receptors (TLRs) can be found ______ of macrophages.
on the cell surface in phagosomes in endosomes
Positive selection mechanisms in lymphocytes occurs ______.
only in T cells due to binding of a TCR to MHC molecules during development and screening in the thymus
Dendritic cells gather material by ______.
phagocytosis pinocytosis extending tentacle-like extensions between epithelial cells to mucosal surfaces
Transmissible spongiform encephalopathies are caused by ______.
prions
An enzyme that uses an RNA molecule as a template to make a complementary copy of DNA is called ______.
reverse transcriptase
When a helper T cell recognizes a peptide presented by a B cell or macrophage, it will ______
secrete cytokines that will assist in the activation of the B cell or macrophage
Pattern recognition receptors (PRRs) detect ______.
signs of microbial invasion
Before enveloped viruses bud from a host cell, specific viral proteins insert into the host membrane. These proteins become ______.
viral spikes
Humoral immunity is generally used to eliminate extracellular antigens such as ______.
viruses in tissue fluids bacteria toxins
Regional
Acting on a variety of cells in the general vicinity of the cytokine's release
Local
Acting only on the very few cells in the immediate vicinity of the cytokine's release
What are the basic functions of helper T cells?
Activation of macrophages Activation of B cells Coordination of activities of B cells, macrophages, and other T cells
The figure shown here is the receptor on the surface of a(n). ______ cell.
B
The cell types that produce MHC class II molecules for exogenous antigen presentation include ______.
B cells macrophages dendritic cells
Most antigens are T-________ , meaning that T-helper cells are required for confirmation.
DEPENDENT
The nucleocapsid is composed of ______.
DNA or RNA and protein.
True or false: Macrophages cannot function to eliminate antigen without assistance from helper T cells.
FALSE ; They can function to eliminate antigen, but they do so more efficiently when they have been activated by helper T cells.
True or false: As its name suggests, the alternative pathway of complement activation serves as a back-up in case the other complement activation pathways fail
False; the name reflects that it was not discovered first; it actually provides vital early warning that an invader is present.
All of the following are usually true of a secondary response EXCEPT ______.
IgM is the primary
What are features of the inflammatory response?
It can damage host tissues. It can help eliminate an invading microbe.
If an immune system lost the ability to make helper T cells, the B cells could still be activated by ______.
T-independent antigens polysaccharides
True or false: Peroxidase enzymes can be found in phagocytic cells.
TRUE
What is it about the traits of a T-independent antigen that can activate a B cell without help from a T cell?
The high number of repeating identical epitopes can cross-link many BCRs at once, providing a strong activation signal without T cells.
Enveloped viruses can derive their envelopes from ______.
certain host organelles the host cytoplasmic membrane
The hepatitis B virus sometimes causes an infection that results in a continuous and low-level production of virus particles. This type of infection pattern is specifically described as a(n) _________viral infection.
chronic
Which type of viral infection is characterized by the continuous, low-level production of new virus particles by animal host cells?
chronic
The cells that have the general role of interacting with target cells and then inducing changes in them are ______.
cytotoxic T cells helper T cells
The three general components of the ____________ immune system are first-line defenses, sensor systems, and effector actions.
innate
In acute viral infections, although the infected host cells may die, the host may survive because ______.
the host's immune system may gradually eliminate the virus
Which of the following are mechanisms that either prevent complement protein activation or protect host cells from activated complement proteins?
Inactivated C3b is not an effective opsonin Proteins on host cells bind and inactivate C3b
The portion of antibody molecules that has a consistent amino acid sequence regardless of the epitope recognized is referred to as the ______ region.
constant or Fc
In latent infections, the virions are ______
only produced following reactivation
Protective outcomes of activation of the complement system include ______.
opsonization inflammatory response cell lysis
A family of proteins called ___________________________receptors (PRRs) allow the body's cells to recognize and bind to a wide variety of ligands found in many pathogens
pattern recognition
A _____ is a vesicle that surrounds and encloses a particle brought into a phagocytic cell by phagocytosis.
phagosome
True or false: Peroxidase enzymes can be found in phagocytic cells. True false question.
True ; This is one of the sets of enzymes used to degrade bacteria ingested by phagocytes.
The human genome ______.
does not have the coding capacity to have one gene per specific antibody molecule
Mutations in the influenza virus genome can result in minor changes in key viral surface proteins. This type of variation is called antigenic _______
drift
A T-cell receptor (TCR) is ______.
only recognizes antigen that is presented by another cell is similar (but not identical) in function to a B cell receptor is found on the surface of T cells
IgG is the only antibody that is transported across the _____ into the fetus's bloodstream.
placenta
In the case of RNA viruses that have a single strand (+) RNA genome, the viral genome ______.
is used as a template to make complementary (-) RNA strands that act as templates to produce more (+) RNA strands can be translated to make proteins
Specific TLRs (toll-like receptors) anchored in endosomes and phagosomes typically detect ______ that indicate microbial origin.
nucleic acids
In an inflammatory response, the diameter of local blood vessels increases due to the action of the chemical __________ and other inflammatory mediators, slowing blood flow in the area. At the same time, changes in the endothelial cells that line the capillaries create small gaps in the normally ___________ junctions between the cells, allowing more fluid to leak from the blood vessels into the tissue.
histamine ; tight
Lysozyme, an enzyme that degrades peptidoglycan in bacteria, can be found ______.
in saliva in tears in phagocytic cells in the mucus of the small intestine
C3 convertase ______.
splits complement component C3 forms at the convergence of the three pathways of complement activation
The interior deep tissues of the body are generally__________ , meaning free of microbes.
sterile
True or false: IgM is the main circulating antibody in the bloodstream.
FALSE ; because it only accounts for about 5-13% of circulating antibody at given time
The variable region on an antibody molecule is found ______.
at the end of the Fab regions
Immune cells communicate with each other through surface receptors, adhesion molecules, and chemical signals known generally as .
cytokines
Which of the following infections are analogous to lysogenic infections by bacteriophages in that they involve a viral genome that is silent in the host cell?
latent
List the steps of an animal virus infection cycle in the correct order. Start with the earliest at the top.
1. attachment 2. penetration & uncoating 3. synthesis of viral proteins & replication of the genome 4. assembly 5. release
There are ________ general types of constant regions that correspond to the major classes of immunoglobulin (Ig, aka antibody) molecules.
5
Chemicals that are secreted by certain cells of the immune system and which act at low concentrations to cause effects on other cells, are known as ________
cytokines
T lymphocytes exist in two major types. Those that are called ________ T cells are responsible for inducing apoptosis in self cells infected with viruses or are otherwise "corrupt".
cytotoxic or killer
Toll-like receptors (TLRs) are present on or in which of the following sentinel cells?
dendritic cells macrophages
The type of T lymphocyte called ________ T cells play a major role in directing and assisting the various immune responses.
helper
A viral infection in which the viral genome is integrated into an animal host cell chromosome, yet can reactivate to cause a productive infection, is categorized as a(n) infection.
latent
The cells of the immune system _____
move from one part of the body to another via the body's circulatory systems
The basic functions of effector cytotoxic cells (TC cells) include ______.
destruction of cancerous self cells induction of apoptosis in infected self cells
HIV is described as a __ _____because it uses reverse transcriptase to make a DNA copy from its RNA genome.
retrovirus
Helper T cells secrete chemical signals known as ________ that stimulate the proliferation of B cells and macrophages.
cytokines or interleukins
The type of T lymphocyte called _________ T cells play a major role in directing and assisting the various immune responses.
helper
All of the following are required for synthesis of new virus particles in a host cell EXCEPT ______.
homologous recombination
The virally encoded polymerase needed for replication of RNA viruses is called a
replicase
If a developing T cell in the thymus recognizes a self antigen bound to an MHC molecule with its T-cell receptor (TCR), that T cell is ______.
eliminated through induction of apoptosis
If a person develops an infection, the number of disease-fighting cells in the bloodstream will ______.
increase because they are recruited from reserves in the bone marrow
In response to tissue damage or introduction of microbes into normally sterile body sites, ___________ occurs. The purpose of this is to contain the site of damage, localize the response, eliminate the invader, and restore tissue function.
inflammation
T cells mature in the ______ and B cells mature in the bone _____
thymus ; marrow
The portion of antibody molecules that has a consistent amino acid sequence regardless of the epitope recognized is referred to as the ________ region.
constant or Fc
True or false: DNA viruses can only replicate when the host cell is replicating its own genome.
False; Many DNA viruses encode their own DNA polymerase and can replicate even if the host cell is not replicating.
True or false: Monocytes are normally found in various tissues of the human body, including lungs, liver, and brain. True false question.
FALSE ; Monocytes travel in the blood. What do we call the further differentiated form of a monocyte that is in the tissues?
Which of the following statements about prions are true?
Infectious prion proteins may convert normal prion proteins into an abnormal form. Infectious prion proteins have a different shape from normal prion proteins. Infectious prion proteins are insoluble and aggregate in brain tissue.
When a B cell receptor (BCR) binds antigen, and the naive B cell is activated by confirmation from a helper T cell, the B cell then begins to ______.
multiply
Cell-mediated immunity (CMI) deals with intracellular pathogens and antigens such as ______.
viruses replicating in a cell
The complement pathway that is activated by binding of C3b to cell surfaces is the _______.
alternative pathway
An antigen is a molecule capable of interacting with ______.
an antibody molecule a B-cell receptor
The term "antigen" is derived from the descriptive expression " ________ generator."
antibody
The main outcome of B cell activation is ______.
triggering the cell to multiply
Why might it be a good thing for a host to kill an infected self cell?
If it's harboring an infectious agent, killing the cell may prevent adjacent cells from also becoming infected by that infectious agent.
______ is the only antibody class that can be transported across the placenta.
IgG
When a macrophage receives assistance from a helper T cell in the form of cytokines, it ______.
activates more potent destructive mechanisms for the cell, enhancing its antigen clearing capacity
Cell-mediated immunity defends against ______.
invaders residing within the cell
The three pathways of complement activation converge at the formation of ______ convertase.
C3
IgG ___
accounts for 80-85% of circulating antibody levels easily leaves the bloodstream and enters tissues
Macrophages have limited killing power until they become ______ macrophages.
activated
clonal
many lymphocytes produced, but each has only one specific epitope it will react with
Understanding the steps of phagocytosis is important medically because ______.
many pathogens are able to evade one or more of them
In enveloped viruses, sandwiched between the nucleocapsid and the envelope is the ______.
matrix protein
The population of microbes that routinely grow on the body surfaces is the normal __________ , or flora.
microbiota
Macrophages have a lifespan of weeks to months. To replace them, ______ leave the bloodstream and differentiate into new macrophages.
monocytes
A _______ is a single virus particle
virion
During viral replication, when the genome of a (+) single-stranded RNA virus is used as a template, which of the following is generated?
(-) single-stranded RNA molecules
A generalized infection cycle of an animal viruses can be divided into five steps:
1. attachment 2. genome 3. synthesis 4. assembly 5. release
Which of the following describes the various viral parts coming together to produce virions?
Assembly
a prion is best describes as ____
a proteinaceous infectious agent
Fever is
a strong indication of infectious disease an important host defense mechanism
A plasma cell is ______.
an antibody-producing descendant of a B cell
Lysozyme breaks down peptidoglycan, a common component of the cell wall of bacteria. What effect would this have on most bacterial cells?
It would leave cells susceptible to lysis due to osmotic pressure imbalances.
Replication of single-stranded DNA viruses is quite similar to that of double-stranded DNA viruses, except that ______.
a complement to the single-stranded DNA molecule must be synthesized
The epithelial cells that line the exposed surfaces of the body are tightly packed together and rest on the ______ membrane.
basement
The viral genome is protected from the environment by a protein shell called the ______.
capsid
A capsid is ______.
the protein coat that surrounds the viral genome
Diapedesis is ______.
the squeezing of leukocytes out of the blood vessels and into an inflamed or infected area
In single strand (+) RNA viruses, ______.
the viral genome functions as mRNA and is translated
Systemic
Acting throughout the organism, and not restricted to a particular area
Positive selection take place in T cells but not in B cells because ______.
B cells don't need to have peptides presented to them on an MHC molecule, so it doesn't matter if they can bind MHC or not
Fill in the blank question. Human body temperature is kept around 37oC by a temperature-regulation center in the ______
BRAIN
Why does opsonization make a microbe easier for a phagocyte to ingest?
Because phagocytes have receptors for opsonin proteins on their surface.
Cell- ___________ immunity deals with microbial invaders residing within a host cell, such as a virus replicating inside a cell, whereas ______ immunity deals with invaders in the bloodstream and tissue fluids.
Blank 1: mediated Blank 2: humoral
C3b is both a product and a trigger for the alternative complement cascade. How can this occur?
C3 is unstable and can spontaneously split into C3a and C3b at a low rate.
In the alternative pathway, the C3 convertase is composed of ______ and other activated (cleaved) complement system proteins.
C3b
The replication strategy of viruses can be divided into three general categories: those used by ______
DNA viruses RNA viruses reverse transcribing viruses
______ gather antigens using pinocytosis, phagocytosis, and sending tentacle-like extensions between epithelial cells to mucosal surfaces.
Dendritic cells
Neutrophils can release their cell contents to form NETs, an acronym that stands for neutrophil ______.
Extracellular traps
Some areas of the body have populations of microbes living on cell surfaces. Select each area that would have normal microbiota.
Large intestine Skin Vagina
_________ , which include B cells and T cells, are the primary cell type involved in the adaptive immune responses.
Lymphocytes
Which of the following statements about virus nucleic acid is true?
Viruses contain either DNA or RNA.
Clonal selection is a critical theme in the adaptive immune response. The two main features are that
a population of lymphocytes able to recognize a functionally limitless variety of antigens is generated each lymphocyte recognizes and responds to only a single epitope
Helper T cells orchestrate the immune response by ______.
activating B cells and macrophages directing the activities of B cells, macrophages, and T cells
Which type of infection can be characterized by the sudden onset of symptoms of a relatively short duration?
acute
Humoral immunity is best at eliminating ______ antigens such as viruses in the bloodstream or tissue fluid, whereas cell-mediated immunity removes ______ antigens such as viruses within host cells.
extracellular; intracellular
The _________ region at the end of each arm of the Y-shaped antibody molecule is responsible for antigen binding.
fab
The two main categories of T lymphocytes necessary to mount a response against foreign pathogens are cytotoxic T cells and __________ T cells.
helper
Two types of T cells are involved with eliminating antigen. What are they?
helper T cells cytotoxic T cells
A cytokine is ______.
secreted by a specific cell type and binds to a receptor on target cells, causing a response in that target cell such as growth or death
The process that B cells use to generate diversity in the B-cell receptors is ______.
similar to the process that T cells use to generate diversity in T-cell receptors
A(n) ______ is an infectious agent that lacks a capsid and consists only of RNA.
viroid
The following steps occur during the B-cell response to T-dependent antigens. Place them in the correct sequence, starting with the earliest at the top.
1. B-cell receptor binds to antigen 2. B cell internalizes antigen 3. B cell degrades antigen into peptide fragments 4. peptide fragments are presented on MHC class II molecules 5. tH cell recognizes antigen fragment & activates B cell
Microbes that have been opsonized are easier to engulf because phagocytes have _______ for opsonin proteins such as C3b on their surface.
RECEPTORS
True or false: The inflammatory process involves a cascade of events that results in dilation of blood vessels, leakage of fluid from those vessels, and migration of leukocytes out of the bloodstream and into the tissues.
TRUE
True or false: IgG accounts for approximately 80-85% of total antibody in the serum.
True ; bc IgG is the predominant type of antibody in the serum.
Memory B cell production occurs ______.
after class switching has taken place
Monocytes travel in the __________ , while macrophages are more differentiated, larger, and reside in tissues, including the liver, spleen, lymph nodes and lungs.
blood
The main reason that blood proteins and phagocytic cells can enter infected tissues during the inflammatory response is that ______
changes in the cells lining the blood vessel walls allow the items to leave the bloodstream and enter the infected area
The stem of the Y-shaped antibodies has a highly ______.
conserved amino acid sequence that provides the "red flag" for other immune system components to eliminate the antigen
Catalase, an enzyme produced by some species of bacteria, _____
creates H2O and O2 as breakdown products breaks down hydrogen peroxide
_______ cells function as sentinel cells, engulfing material in tissues and taking it to adaptive immune system cells for inspection.
dendtritic
Which of the following are non-cellular infectious agents composed of only a single-stranded RNA molecule?
viroids
The name of the alternative pathway of complement activation reflects the fact that it _____
was not discovered first
_______ are responsible for adaptive immune responses and include two major groups: B cells and T cells.
lymphocytes
are viruses that are capable of infecting and selectively killing cancer cells
oncolytic viruses
All of the following are true of antigen processing and presentation in B cells EXCEPT ______.
peptide fragments are loaded into B cell receptor molecules for presentation to helper T cells
An example of adhesion molecules in action occurs when ______ cells are needed in the tissues. The ______ cells lining the blood vessels make adhesion molecules to "grab" these cells from the blood.
phagocytic; endothelial
_____ are the causative agents of transmissible spongiform encephalopathies.
prions
Which of the following are non-cellular infectious agents?
prions viroids viruses
If a macrophage's pattern recognition receptors (PRRs) detect bacterial products, then that macrophage will produce ______
pro-inflammatory cytokines
Symptoms of acute viral diseases result from ______.
host immune response host tissue damage
True or false: The deeper interior tissues of the body are generally laden with helpful symbiotic bacteria.
FALSE ; Indeed, the deeper interior tissues of the body are generally sterile, except during infections.
Recognition of endogenous antigens by effector T cells involves presentation of antigen _______.
to cytotoxic T cells
True or false: Normal prion proteins can have the same amino acid sequence as the abnormal form of the protein.
true; the proteins differ in their folding and shape
An abnormal growth of tissue resulting from a malfunction in the normally highly regulated process of cell growth is a _____
tumor
The amino acid sequence of the end of the "arms" of different antibody molecules is ______.
variable, thus providing the basis for antibody specificity to antigens
How do immune cells communicate with each other?
via adhesion molecules via surface receptors via cytokines
A complete viral particle, which typically consists of nucleic acid surrounded by a protein coat, is called a(n)
virion
Maternal IgG can protect a newborn after birth by ______.
virtue of its long half life--it is present in the newborn's blood for nearly 6 months after birth being present in colostrum, the first breast milk produced after birth, supplementing the IgG carried in the newborn's blood after it is born
The capsid of a virus is composed of precisely arranged identical protein subunits called
capsomers
At a minimum, all viruses are composed of ______.
proteins nucleic acids
A macrophage usually kills microbes by ______, while a neutrophil can additionally kill by ______.
ingesting microbes and destroying them internally; releasing toxic granule components