ch 9 The Immune System

The following are steps in phagocytosis: (1) Bacterium is digested by lysosomal enzymes; (2) phagocyte approaches bacterium; (3) phagocytic vesicle fuses with lysosome; and (4) phagocyte engulfs bacterium, forming a phagocytic vesicle. In which order do these steps occur?

2-4-3-1

Before __________, there was no recommended screening for HIV even though the Centers for Disease Control and Prevention had been recommending such procedures since 2006.

2013

There are four bacteria in an egg salad that is left out at room temperature. After two hours, how many bacteria will be in the egg salad?

256 The bacteria would double 6 times in 2 hours, so the total number of bacteria in the egg salad would be 256.

When a person is infected with Plasmodium vivax, that person undergoes chills and fever about every ________ hours. This event corresponds with the ________.

48; release of the parasite from the red blood cells. With Plasmodium vivax, this phenomenon occurs every 48 hours and corresponds to the release of the parasites from the red blood cells

A person is diagnosed as HIV positive. Why is the level of that person's helper T cell level monitored? Helper T cells are the target of HIV. Helper T cells stimulate the cytotoxic T cells, which can defend the body against the HIV infection. Helper T cells stimulate B cells, which produce antibodies against the virus.

All of the listed responses are correct. The helper T cells are HIV's target and it is the helper T cells that stimulate cytotoxic T cells as well as B cells.

Based on this research, which of the following studies would likely be best to create better treatments for future C. diff outbreaks?

An in-depth study of the gut microbiome in humans.

If trends continue, which of the following will occur?

An increase in the number of cases of alpha-gal allergy as the tick increases its range.

Which of the following does NOT belong with the others?

Anaphylactic shock

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____.

B cells ... plasma cells and memory cells The antigen-selected proliferation of B cells produces clones of plasma cells and memory cells.

In which of the following ways are bacterial cells similar to human cells?

Bacterial cells use ATP to fuel cellular activities.

A Lone Star tick carries alpha-gal. Which of the following is the most likely way the tick was infected?

By biting an animal that had alpha-gal.

Which structure helps bacteria to attach within the tissues that they will infect?

Capsule The gelatinous capsule that covers some bacteria helps them attach to the tissues that they will infect.

Why are children more likely to pick up germs in public places?

Children tend to be more tactile, and may not wash their hands as often as they should.

Which of the following would be the best experimental design for a study looking at the effect of hand-washing on the incidence of acquiring an infectious disease?

Choose a setting where a large number of people consistently spend time, such as an office building. Randomly assign everyone to one of two groups. Ask one group to wash their hands every hour, and ask the other group to avoid washing their hands except when truly necessary. Compare the incidence of infectious disease between the two groups over a period of months or years.

Cancer cells would be attacked by which of the following cells?

Cytotoxic T cells Yes, cytotoxic T cells attack cancer cells, since they are part of cell-mediated immunity.

What is the final step in the cell-mediated response to a viral infection?

Cytotoxic T cells punch holes in the membranes of infected host cells. This event causes infected host cells to burst and die and prevents the virus from spreading to other cells.

Which period of infection represents the immune system and/or pharmaceutical intervention working at its peak performance?

D The number of microbes is steadily decreasing due to the activity of the immune system or pharmaceutical intervention. As a result, the signs and symptoms associated with the infection are also dissipating.

A C. diff outbreak occurs in a nursing home. Which of the following would likely be best to stop the outbreak?

Disinfect all areas for spores.

Which of the following would be the best experimental design for a study looking at the risk of getting an infectious disease from using public transportation?

Follow a very large set of people in order to reduce the effect of socioeconomic status. One group is comprised of people who frequently use public transportation, and the other group never uses public transportation. Compare the incidence of infectious disease between the two groups. Collect data without telling the participants too much about the study, so that they do not alter their normal behaviors.

Which of the following statements about HIV is true?

HIV specifically impairs the cell-mediated immune response.

_____ interact with the antigen-class II MHC complex presented by macrophages.

Helper T cells Specific helper T cells recognize specific antigen-class II MHC complexes. The result of this is an activated helper T cell that stimulates both humoral and cell-mediated immune responses.

While working as a microbiologist, you discover a new species of Clostridium. Which of the following is true?

It is most likely harmless.

Which of the following statements best describes the end result of bacterial conjugation?

One cell has given a copy of a plasmid to another cell and kept one copy for itself. Both cells end up with a copy of the same plasmid.

Which of the following is a benefit of resident bacteria?

Resident bacteria can out-compete harmful bacteria and lower the incidence of infection.

In the mock-up of an airplane cabin, there were heated yellow bags where people would normally sit. Why?

The bags are added to create an experimental model that would be most similar to an actual plane full of people.

From which cell does the sex pilus originate during bacterial conjugation?

The donor cell The sex pilus originates from the donor cell.

You are prescribed antibiotics for strep throat. Which of the following is true?

The drug will kill many kinds of bacteria.

When discussing the sequence of events in the body of the mosquito, which of the following can we say?

The gametocytes head for the gut, unite to form a zygote, migrate to the outer wall of the intestine, and are released to the salivary gland. The gametocytes go to the gut, unite to form a zygote, migrate to the outer wall of the intestine, and are released to the salivary gland.

What happens when a mosquito infected with malaria bites a human?

The larval parasites flow from the salivary gland of the mosquito into the blood of the human and head for the human liver. The larval parasites flow from the mosquito's salivary gland, into the human blood circulation, and on to the liver. Incorrect. The larval parasites flow from the salivary gland, into the blood, and on to the liver.

How does HIV bind to a host cell?

The viral envelope proteins bind to CD4 and a co-receptor. The viral envelope proteins interact with CD4 and a co-receptor on the host cell membrane to allow the virus to fuse with the host cell's membrane.

HIV is a retrovirus. Which of the following is NOT a part of the retrovirus scenario?

The viral envelope proteins interact with CD4 and a co-receptor on the host cell membrane to allow the virus to fuse with the host cell's membrane. This statement is not true. The RNA of the retrovirus is converted into DNA that functions in the nucleus and not in the cytoplasm.

Consider the following group of diseases: hepatitis, chicken pox, warts, and measles. What do these diseases have in common?

They are all caused by viruses

What do lysozyme, keratin, and mucus have in common?

They are all part of the first line of defense. All participate in preventing a pathogen from entering the body.

Which of the following is true regarding prion diseases?

They cause accumulation of misfolded proteins in brain cells

What is the role of mast cells in the inflammatory response?

They release chemicals that dilate blood vessels at the wound site. Mast cells release histamine, which causes dilation of arterioles and leads to increased blood flow to the injured tissue.

Which of the following statements about plasma cells is FALSE?

This statement is false. Plasma cells are effector B cells and not part of the MHC system. Therefore, this is the correct answer.

Which of the following is true regarding alpha-gal allergy?

Those affected may outgrow the allergy over time.

What is the most likely reason an HIV-positive person might develop thrush and/or shingles?

Thrush and shingles are caused by opportunistic organisms. An HIV-positive person has a compromised immune system and is vulnerable to infection by these and other organisms. Thrush and shingles are caused by opportunistic organisms and are thus able to cause disease in the immune-compromised HIV-positive person.

True or false. Bacteria reproduce by an asexual process in which one parent cell gives rise to identical daughter cells.

True Bacteria reproduce by binary fission, which is an asexual process in which one parent cell splits in two to give rise to identical daughter cells.

True or False. During bacterial conjugation, the recipient cell receives a single-stranded loop of DNA.

True One strand of the plasmid enters the recipient cell; this strand must be replicated in the recipient cell to produce a double-stranded plasmid that can replicate independently of the bacterial chromosome.

For what reason does the recommendation of the U. S. Preventative Services Task Force (USPSTF) carry more weight than the CDC for the screening of all adults between the ages of 15 and 64?

Under the Affordable Care Act private insurance companies are required to pay for preventive services that the USPSTF recommends with grades of "A" or "B". These recommendations were given a grade "A" level of approval.

Which of the following statements about viruses is true?

Viruses require a host cell in which to reproduce.

You are bitten by a Lone Star tick. Which of the following is true?

You could get one of a number of illnesses.

You are a doctor. A patient presents with diarrhea and tests positive for C. diff. Which of the following is true?

Your patient may or may not have recently taken antibiotics.

Which setting has the shortest time span for air refreshment - in other words, which setting has the most frequent air exchange with fresh air?

airplane cabin

Which of the following increases the likelihood of successful organ transplant?

all of these choices

What is the name of the unique area (specific region) that a lymphocyte recognizes and binds to?

an antigenic determinant Yes, also called an epitope, the antigenic determinant is the specific part of an antigen that the antibody or lymphocyte antigenic determinant receptor binds to.

The urinary tract represents a portal of entry for E.coli, a normal inhabitant of the GI tract. Introduction of this opportunistic pathogen and its subsequent colonization is known as __________.

an infection An infection represents an invasion or colonization by a pathogen.

Structures that precipitate antigens, promote lysis, attract phagocytes, and neutralize toxins are called ________.

antibodies Antibodies defend the system by precipitating antigens, promoting lysis, attracting phagocytes, and neutralizing toxins.

Which of the following act(s) as a neighborhood watch group, looking for specific invaders in the blood or other fluids that have compromised the first two lines of defense?

antibody-mediated immunity Antibody-mediated immunity represents a third line of defense that is more specific in its response. These antibodies target specific pathogens freely circulating in blood or other fluids.

Both viruses and prions __________.

are pathogenic Both viruses and prions are pathogenic. Only prions cause misfolding of proteins.

During which stage of HIV infection are viral levels in the blood at their lowest?

asymptomatic stage During the asymptomatic stage, the immune system "controls" the infection and circulating virus levels drop; during this stage, the virus is "hiding out" in the lymph nodes and other lymphatic organs.

Each of the following processes helps combat infection, EXCEPT __________.

autoimmunity

In which of the following choices is the cell correctly matched with its function?

basophil: secretes histamine

If a virus attacks a cell, which type of immunity would be activated?

cell-mediated immunity (cellular immunity) Yes, cell-mediated immunity involves an intracellular pathogen such as a virus.

Lymphatic vessels are similar to veins in that they both __________.

contain one-way valves to prevent the backflow of fluid Both veins and lymphatic vessels contain one-way valves.

Activation of a B cell leads to all of the following, EXCEPT __________.

destruction of cytokines Cytokines are part of the body's defense in cell-mediated immunity.

True or false. When you suffer an injury, white blood cells near the injury site initiate the inflammatory response.

false The injured tissue releases chemicals that begin the inflammatory response.

In an airplane, from whom are you most likely to acquire a cold or flu virus?

from a sick person sitting next to you

The pointer is indicating the virus's _____.

genome The pointer is indicating the virus's nucleic acid genome.

The direct cause of the heat generated by a wound or local infection is ________.

histamine, which causes the smooth muscle cells of the arterioles to relax; this leads to a cascade of events causing the tissue to become hot Histamine, released by the mast cells, causes the smooth muscle cells of the arterioles to relax and ultimately leads to the heat apparent in the infected tissue.

What type of immunity can be transferred by bodily fluids from one person to another, thus conferring immunity to the recipient?

humoral immunity Yes, humoral immunity involves antibodies that can be transferred from one person to another.

Major histocompatibility complex (MHC) proteins __________.

identify a body cell as "self" MHC proteins are cell-surface markers that identify a cell as "self." MHC proteins are not produced by B cells.

Tears and mucus membranes would be a part of which defense system?

innate external defenses Yes, innate external defenses (surface barriers) are the first line of defense and include tears, mucus membranes, and the skin.

Phagocytotic cells such as macrophages identify a variety of enemies by recognizing markers unique to pathogens. They would be classified as which type of defense system?

innate internal defenses Yes, the macrophage recognizes many molecules found on pathogens that are not present on normal body cells.

Which of the following represents the first line of defense against unwanted pathogens?

intact skin Skin represents an obstacle to entry by microbes. This is because the cells are tightly packed together, acting as a physical barrier to invasion. In addition, the skin also secretes chemicals that have antimicrobial properties, further protecting the host.

DiGeorge syndrome is a congenital disease that results in a poorly developed, nonfunctioning thymus gland. Which of the following would be a likely problem experienced by a baby with DiGeorge syndrome?

lack of T cells

The primary immune response is __________.

less effective than the secondary immune response

Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium?

macrophage Macrophages are phagocytic leukocytes.

Which of the following types of cell can ingest pathogens?

macrophages Macrophages are phagocytic cells that can ingest pathogens; they can also present antigens to helper T cells.

Fever is caused when __________ release __________.

macrophages; pyrogens Pyrogens are produced by macrophages and do produce fever.

Which of these cells is responsible for the rapidity of the secondary immune response?

memory cells Memory cells are responsible for the rapidity of the secondary immune response and for long-term immunity.

What type(s) of cell(s) can helper T cells become?

memory helper T cells and effector helper T cells Helper T cells can develop into both memory helper T cells and effector helper T cells.

Which of the following is NOT a major factor affecting the danger of a pathogen?

mode of metabolism While this can affect the danger of a pathogen, it is not a major factor.

Which of the following is not associated with all cell types?

nucleus The nucleus is exclusive to eukaryotic cells and is an important distinguishing characteristic between the two cell types.

A person is exposed to the same pathogen for a second time and does not get sick. This is because __________.

of the secondary immune response The secondary immune response is faster, longer lasting, and more effective than the first.

The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response

perforin ... cell-mediated Perforin causes the lysis of pathogen-infected body cells; it is a component of the cell-mediated immune response.

What cells make antibodies?

plasma B cells Yes, the plasma B cells make antibodies in response to specific antigens

Which of these cells produce and secrete antibodies?

plasma cells Plasma cells are clones of antibody-secreting B cells.

B cells that have been stimulated by interleukin-2 develop into _____.

plasma cells Plasma cells develop from B cells that have been stimulated by the interleukin-2 secreted by helper T cells.

Characteristics of bacteria include all of the following, EXCEPT __________.

presence of membrane-bound organelles Only eukaryotes have membrane-bound organelles.

Which of the following pathogenic agents cause a self-propagating misfolding of proteins in nerve cells?

prions

While exploring a local wooded area, you encounter what you believe to be a previously uncharacterized organism. Upon microscopic evaluation, you notice a single-celled organism about 1 micrometer, lacking a nucleus. What type of cell is this?

prokaryote The lack of a nucleus is indicative of a prokaryotic cell.

Which of the following enzymes cuts a single viral polypeptide into distinct structural proteins?

protease Protease clips the viral polypeptide into multiple, distinct structural proteins.

Malaria is caused by a ________ of the genus Plasmodium and requires two hosts, ________ and ________, to complete its life cycle.

protozoan; mosquito; human Malaria is caused by a protozoan and does require both the mosquito and the human to complete its life cycle.

The spleen __________.

removes damaged red blood cells from circulation The spleen destroys old and damaged red blood cells

When speaking of malarial gametocytes, we can say that ________.

some of the parasites in the blood differentiate into male and female gametocytes and are picked up by another mosquito to complete their life cycle. The gametocytes are formed in the human blood and are picked up by a mosquito.

A specific antibody will bind to __________.

specific antigen Antibodies recognize and bind to a specific antigen.

Which of the following conditions would NOT necessarily result in a diagnosis of AIDS in an HIV-infected individual?

swollen lymph nodes Swollen lymph nodes could appear during the asymptomatic stage or later as part of the initial disease symptoms. Both of these stages occur well before a diagnosis of AIDS

A patient enters your office, feeling achy and tired. Subsequent evaluation reveals a temperature of 103.8 oF. The achy and tired feeling represents a _____ of infection, and a temperature of 103.8 oF represents a _____ of infection.

symptom; sign The feelings of achiness and tiredness are not measurable and are felt only by the infected individual. This represents a symptom of infection. Signs of infection are observable and/or measurable, and they tend to be more specific than symptoms.

Autoimmune disorders occur when __________.

the immune system fails to recognize "self" cells. Autoimmune disorders occur when the body fails to recognize "self" cells and attacks its own cells as foreign.

When talking about the reconstruction of the HIV virus, we can say that ________.

the ribosomes on the endoplasmic reticulum are responsible for production of the viral envelope proteins These proteins eventually end up on the host cell's membrane and can become part of the new viral particle's envelope.

The pain associated with the inflammatory response is the direct result of ________.

the swelling of the tissue and the chemicals released from certain cells. The swelling and the chemicals may both stimulate surrounding sensory neurons and this brings about pain.

Inflamed tissue turns red because ________.

there is an increased blood flow to the injured tissues due to dilation of arterioles in the injured area The localized increase in blood flow is often seen as redness surrounding the injured tissue as histamine relaxes the smooth muscle in the vessels

What is the major method of transmission of infectious disease when using public transportation?

touching surfaces that sick people have touched

Viral DNA makes mRNA by the process of _____.

transcription Viral DNA co-opts the cell's reproductive machinery.

Your friend is diagnosed with an alpha-gal allergy. Which of the following would be best for her to order at a restaurant?

turkey sandwich

Specific defense mechanisms differ from nonspecific defense mechanisms in that only specific mechanisms __________.

utilize B cells and T cells The action of B cells and T cells is triggered only by a specific antigen.

The target of the HIV virus is the ________.

white blood cell subset called helper T cells, also known as CD4+ T cells The white blood cell subset, the CD4+ T cells, is the target of this virus because they carry the CD4 protein and co-receptor molecules on their cell membranes.