Microbiology Chapter 14 HW

Interferons, complement, lysozyme, and lactoferrin are all examples of

nonspecific antimicrobial factors

C3b is involved in

opsonization

The "voices" of a cell, which carry messages, are

cytokines

The cells primarily involved in all immune responses are the

leukocytes

Macrophages sometimes produce a chemical called TNF (tumor necrosis factor) in order to alert other cells of the immune system. TNF would be an example of a(n)

cytokine

If a person lost the ability to make monocytes, he/she would also lose the ability to make

macrophages AND dendritic cells

A group of interacting serum proteins that provide a nonspecific defense mechanism is

complement

IL-2, which is produced and secreted by helper T cells, causes the proliferation of other T cells in the vicinity. Based on this information, we can conclude that IL-2 is a(n):

cytokine

The cells responsible for adaptive immunity are the

lymphocytes

Allergic reactions mainly involve

mast cells

The complex resulting from complement activity that leads to cell lysis is the

membrane attack complex.

The first kind of leukocyte lured to the site of inflammation is the

neutrophil

A pathogen that can avoid binding by complement C3b would directly protect itself from

opsonization

Which of the following statements about interferon is incorrect?

It prevents the entry of viruses into nearby cells. True: It indirectly causes virally-infected cells to undergo apoptosis. It causes nearby cells to produce antiviral proteins. It does not directly inactivate viruses. It is produced by host cells in response to viral RNA.

Toll-like receptors (TLRs) bind molecules on pathogens. Why is this helpful to the immune response?

It provides a general response to broad categories of molecules/cells that should NOT be in our system, as we don't have these molecules on our own cells.

Which of the following are phagocytic cells found in the human body?

Neutrophils AND macrophages

Which of the following is mismatched regarding protection of the body from pathogens?

Stomach—acid conditions and normal microbiota

Please select the TRUE statement regarding Toll-like receptors (TLRs).

TLRs allow cells to detect patterns associated with microbes, indicating that the innate immune responses involve some specificity (although not the specificity of adaptive immunity).

Which of the following pattern recognition receptors is/are anchored in the host cell membrane?

TLRs and CLRs

Which statement about skin and mucous membranes is NOT correct?

They are the first line of adaptive immunity. They are the first line of innate immunity. They separate us from our environment. They act as physical barriers to infection. They contain antimicrobial secretions.

Fever

inhibits bacterial growth AND speeds up the body's reactions

Skin and mucous membranes are mostly involved in

innate immunity

Factors that work generically against any foreign substance entering the host are described as

innate immunity.

Defensins are short antimicrobial peptides found within mucous membranes and phagocytes.

true

If a cell did not express any of the pattern recognition receptors (PRRs), to which of the following would it still respond?

Cytokines

What is apoptosis?

A type of programmed cell death

Which of the following is a bacterial product?

Colicin

Which of the following is least likely to be detected by pattern recognition receptors?

Enzymes involved in glycolysis

Match the following cytokines with their general functions. -chemokines -colony-stimulating factors -interferons -interleukins -tumor necrosis factor

-These cytokines are important in the chemotaxis of immune cells. -These cytokines are important in the multiplication and differentiation of leukocytes. -These cytokines are important in the control of virally-infected cells. -These cytokines are produced by leukocytes and are important in both innate and adaptive immunity. -These cytokines are important as triggers for inflammation and apoptosis.

Complete the following diagram of the different activation pathways of the complement system.

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Label the body diagram with the correct type of mononuclear phagocytic cells associated with that body part. Not all labels are used.

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Label the following diagram showing the body's borders to better familiarize yourself with the first line defenses.

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Label the following diagrams of stratified and columnar epithelium to better understand the body's epithelial barriers. Not all labels are used.

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Match the examples of antimicrobial substances with the corresponding areas in the human body where they function. Not all labels are used.

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Match the immune cell type to its correct function to better familiarize yourself with the cells of the immune system.

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Please label the figure to show your understanding of the innate immune response. Not all labels are used.

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Please move the correct terms into their corresponding empty boxes within the figure to complete the figure.

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Which of the following statements about innate immunity are FALSE?

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Check the TRUE statements about fever induction and outcomes.

-Fever is induced by cytokines called pyrogens. -Fever inhibits bacteria from growing by inhibiting their metabolism. -Fever results when macrophages detect microbial invaders and release pro-inflammatory cytokines. -Pyrogens have an effect by acting on a certain part of the brain.

Please place the sequence of events in inflammation into the correct order.

-Inflammatory mediators are released in response to tissue damage and microbial invaders. -Blood vessels dilate and become leaky; blood flow in capillaries slows. -Endothelial cells "grab" phagocytes which then move into the tissues by diapedesis. -Neutrophils remove and destroy invaders. -Macrophages ingest dead bacterial cells and debris. -New capillaries form, destroyed tissues are replaced, and scar tissue forms.

Which of the following are considered physical (versus chemical) factors that contribute to the skin and mucous membranes protective role against infection?

-Layers of cells -Mucociliary escalator -Flushing of urinary tract

Identify all the functions and characteristics that are associated with macrophages but not with neutrophils.

-Live for weeks to months. -Can fuse with other cells of the same type to form giant cells. -Continually regenerate their lysosomes.

Please match the cell to the statement that most accurately describes its main function to test your understanding of blood cells that function in nonspecific immunity. -neutrophils -basophils -monocytes -NK cells

-Main phagocytes in circulation -Like eosinophils, they are involved in inflammation and allergic reactions -Phagocytic cells that leave circulation and differentiate into macrophages -Display no antigen specificity but are active against tumor and virally infected cells

Match the correct type of pattern recognition receptor (PRR) with the statement describing its function -interferons -RLRs -TLRs -NLRs

-These proteins are often secreted when viral RNA is detected which signals neighboring cells to express antiviral proteins. -These proteins are found in the cytoplasm and can detect viral RNA -These receptors are found anchored in sentinel cells like macrophages and dendritic cells.They can bind to foreign structures like dsRNA, ssRNA and some bacterial DNA fragments -These proteins are found in the cytoplasm and can detect bacterial components.

A medical technician examines a Gram stain of purulent discharge (pus) from a patient with an active infection. Which predominant host cell type will the technician most likely see?

-neutrophils

Which of the following is the correct sequence of events in the interferon response? 1. IFN induces synthesis of inactive antiviral proteins (iAVPs). 2. Virus enters host cell (cell 1) and replicates, producing long dsRNA. 3. Activated AVPs induce apoptosis of infected cell. 4. dsRNA induces synthesis and secretion of IFN to neighboring cells. 5. Entry of virus into cell armed with iAVPs (cell 2) activates these proteins

2, 4, 1, 5, 3

People who have compromised first-line defenses are susceptible to opportunistic pathogens. Which situation would be an example of a compromised first-line defense?

A burn patient who has lost extensive areas of the skin.

Iron

All of the answer choices are correct: is required by microorganisms. binds to lactoferrin. is necessary for the functioning of some enzymes. binds to transferrin.

Which of the following are lymphocytes?

B cells, T cells, AND NK cells

A physician is attempting new therapies for HIV patients who are suffering from an impaired immune response. He decides to try using a recombinant form of colony-stimulating factor cytokine (CSF). Why?

CSF will help to stimulate the production of new lymphocytes, the very cells that are affected by HIV. This may help to keep the patients' immune responses "normal" for a period of time.

Which of the following is NOT an outcome of fever?

Direct destruction of microbes.

Which of the following statements about normal microbiota is FALSE?

Disruption of the normal microbiota has little effect on the host True: -Normal microbiota provides protection by competitive exclusion of pathogens. -Normal microbiota is essential for development of the immune system. -Normal microbiota provides protection by producing bacteriocins. -Normal microbiota sometimes causes disease in the host.

What two functions do phagocytes serve in immune responses?

Engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader.

Fever allows the body to fight microbial invaders by which of the following mechanisms?

Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.

The complement pathway that is activated by mannan-binding protein is the

lectin pathway

A lack of which component would have the greatest impact on a person's health?

Hematopoietic stem cells

Which of the following would NOT trigger an inflammatory response?

Induction of antiviral protein synthesis by IFNs.

Please identify the INCORRECT definition regarding innate immunity.

Innate lymphoid cells—a group of lymphocytes that have increased specificity in their mechanism of antigen recognition (example: natural killer (NK) cells). True: -RIG-like receptors—a group of pattern recognition receptors within cells that recognize molecules associated with infecting viruses. -Sentinel cells—host cells that help the immune system detect signs of invasion by producing cytokines when their PRRs recognize an invading microbe. -Inflammatory response—coordinated innate response involved in containing a site of damage, localizing the response, eliminating the invader, and restoring tissue function. -First line defenses—the barriers that separate and shield the interior of the body from the surrounding environment (skin and mucous membranes).

Which of the following cytokines is most antiviral in its action?

Interferon

Which of the following statements about interferon is TRUE?

It is produced in response to double-stranded RNA.

How are macrophages and neutrophils similar, and how are they different?

Macrophages and neutrophils are both phagocytic cells. Macrophages reside in the tissues while neutrophils typically circulate in the blood.

Which of the following statements about phagocytosis is FALSE?

Macrophages die after phagocytosing bacteria, but neutrophils survive.

Phagocytes were first discovered and named by

Metchnikoff

The body's own cells do not trigger the alternative pathway of complement system activation. Why is this?

Molecules in host cell membranes bind regulatory proteins that will inactivate any C3b molecules that attach to the membrane.

Please identify the mismatched pair.

Peritoneal macrophages—meninges True: Alveolar macrophages—lungs Microglial cells—brain Mesangial macrophages—kidneys Kupffer cells—liver

Which of the following are enzymes found in neutrophil granules, saliva, and milk that react with hydrogen peroxide to form antimicrobial compounds?

Peroxidases

Which activity of the virally invaded cell triggers production of interferon?

Production of dsRNA

Which of the following are danger-associated molecular patterns (DAMPs)?

RNA DNA phospholipids nucleotides

The four cardinal signs of inflammation are

Redness, heat, swelling, pain

Smoking impairs the ciliated cells of the middle portion of the respiratory tract. Many analgesic drugs (painkillers) impair peristalsis (the churning motion of the digestive tract). The result of either of these activities leads to an increased risk of infection in their respective areas. Why?

The actions of the cells in these areas help to propel pathogens out of the area, serving as a part of the physical barrier system. When they are impaired/slowed, bacteria and other pathogens have an easier time adhering to the tissues in the area and causing an infection

Inactivation of a cell's interferon genes would likely have which outcome?

The cell would no longer alert neighboring cells to the presence of double-stranded RNA.

Syphilis, an STI, was once treated by intentionally infecting the patient with the parasite that causes malaria, a disease characterized by repeated bouts of fever, shaking, and chills. Why might this treatment cure syphilis?

The effect of driving up the body temperature for periods of time can shut down the temperature-sensitive replication of the bacterium that causes syphilis. This gives the immune system time to eliminate it properly

Which statement about complement proteins is FALSE?

They are part of the specific immune defense system. True: -They are a group of blood proteins produced by the liver. -They are part of the innate immune response. -They may be activated through three different pathways. -They disrupt the cytoplasmic membrane of invading bacteria and foreign cells.

Which of the following is not true of phagocytosis?

Within a phagolysosome, O2 consumption decreases dramatically, allowing an enzyme to produce reactive oxygen species (ROS), which are toxic.

A cell infected by viruses may die due to the actions of interferons. The same result would occur WITHOUT interferon—any cell infected by a virus would die directly from the virus. Is there any apparent benefit to the host organism from the interferon action?

Yes; when the interferon acts on a virally infected cell, it shuts down virus replication. Without interferon, the virus will eventually kill the cell, but only after it has replicated many times. IFNs may kill the host cell, but they will also prevent it from being used to replicate virus.

Based on what you know of the events in inflammation, the cell labeled "A" is likely to be

a neutrophil.

Apoptosis is

a type of cell death that does not initiate inflammation

The complement pathway that is activated by binding of C3b to cell surfaces is the

alternate pathway

Which is not a component of innate immunity?

antibody

Normal microbiota

are the organisms that typically reside on and in your body AND protect against infection by pathogens.

In humans, the stem cells from which all blood cells arise are found in the

bone marrow

The attraction of leukocytes to the area of inflammation is referred to as

chemotaxis

The complement pathway that requires antibodies to be activated is the

classical pathway

C3a and C5a are involved in

inflammation AND attraction of phagocytes

Toll-like receptors

each recognize a specific "danger" molecule AND are embedded in cellular membranes.

Fever often enhances bacterial survival during an infection.

false

Gram-negative bacteria are less susceptible to complement lysis than Gram-positive bacteria.

false

Interferon directly interacts with and destroys viruses.

false

Mast cells are only found in the blood.

false

Neutrophils are the second phagocytic cell to respond to an infection.

false

All blood cells originate from the

hematopoietic stem cell

Interferons secreted by a viral-infected cell

prevent viral replication in nearby cells.

Interleukins are

produced by leukocytes AND protein molecules.

Toll-like receptors (TLRs) bind molecules on pathogens. This is helpful to the immune response because TLRs

recognize broad categories of molecules that should not be in our system, as we don't have these molecules on our own cells.

Which of the following is a function of the mucociliary escalator?

removes microbes from the respiratory tract

During apoptosis, a cell will

self-destruct without causing an inflammatory response

In which organism were phagocytes first reported?

starfish larvae

Which is not involved in adaptive immunity?

tear flow

Lymphocytes are the cells primarily responsible for the adaptive immune responses.

true

Pattern recognition is involved in innate immunity.

true