AP Bio Immune System Quiz
An antibody can be best classified as which of the following? Possible Answers: A virus A protein An enzyme A cell
Correct answer: A protein Explanation: Antibodies are proteins created by the immune system in order to neutralize foreign objects. An antibody would not be classified as an enzyme because it does not catalyze chemical reactions. When a foreign pathogen enters the body, it will have foreign receptors on its surface. These foreign receptors are known as antigens. When a pathogen is destroyed, immune cells can carry a sample of the antigen to the T-cells for identification. The T-cells help activate B-cells that will synthesize an antibody against the particular antigen. The selected B-cells differentiate into plasma cells and secrete antibody proteins into the blood, which bind the antigens and label the pathogen as foreign. This label attracts other immune cells to attack and destroy the pathogen.
Which immune system response could best be characterized as adaptive? Possible Answers: The epithelium of the skin blocks most pathogens from ever entering the body After the first exposure to an antigen, memory B-lymphocytes are produced to recognize the same antigen upon a second exposure In the inflammatory response, mast cells produce histamine to facilitate the travel of immune cells and plasma to the afflicted area A phagocyte engulfs and destroys bacteria, dead cells, and other potentially harmful particles that it encounters
Correct answer: After the first exposure to an antigen, memory B-lymphocytes are produced to recognize the same antigen upon a second exposure Explanation: The two types of immune system responses are innate (nonspecific) and adaptive (specific). Innate responses are those that act on many pathogens in the same general way. For example, the skin and the mucus in the nasal cavity both physically block the entry of pathogens into the body, but they do not specifically target certain antigens. Other examples of the innate response are inflammation and the general activity of phagocytes. On the other hand, the adaptive immune system provides a second line of defense against certain, previously encountered pathogens. Here, the only answer choice that deals with the recognition of specific antigens is the production of memory B-lymphocytes. The adaptive immune response generally involves T-lymphocytes, B-lymphocytes, antigens, and antibodies.
Immunoglobulins (also known as antibodies) can work in many ways. Which answer option describes a mechanism of immunoglobulin function? Possible Answers: Precipitation All of the other answers Neutralization Complement fixation
Correct answer: All of the other answers Explanation: All of the given answer options describe mechanisms for immunoglobulin function. Neutralization occurs when the antibodies simply cover the biologically active portion of the pathogen, rendering it harmless. Complement fixation refers to the antibodies binding to the pathogen and facilitating the activation of the complement system (a series of plasma proteins that activate other immune processes). Precipitation is when antibodies link the antigens on many pathogens together, creating an insoluble clump ready for removal.
Which of the following statements best represents antigen presentation in an acquired immune response to a pathogen? Possible Answers: Antigen from the pathogen is presented to memory helper T-cells to stimulate a new round of B-cell clonal selection and antibody response Antigen presenting-cells present antigens memory helper T-cells, followed by memory B-cells followed, by memory T-cells Antigen from the pathogen is presented specifically to memory T-cells to activate cytotoxic T-cells to clear the infection Antigen from the pathogen is presented simultaneously to memory helper T-Cells, memory T-cells, and memory B-cells
Correct answer: Antigen from the pathogen is presented simultaneously to memory helper T-Cells, memory T-cells, and memory B-cells Explanation: An acquired immune response to a secondary infection by a pathogen results in presentation of antigen to residual memory helper T-cells, memory T-cells, and memory B-cells. Upon recognizing the antigen, memory T-cells can become cytotoxic T-cells and target the infected region. The process of presentation promotes direct expansion of the existing population of immune cells already capable of responding to the pathogen. Immunological memory provides a more rapid response time to combat the pathogen during the second exposure.
Which of the following cells is exclusive to the adaptive immune system? Possible Answers: Mast cells Neutrophils Dendritic cells Macrophages B-cells
Correct answer: B-cells Explanation: The adaptive immune system primarily relies on the function of B-cells and T-cells. T-cells help recognize antigens to which the body has been previously exposed and stimulate B-cell to release antibodies to combat that specific antigen. Upon initial antigen exposure, all other cell types listed (which help comprise the innate immune system) kick in.
Immunoglobulins (also known as antibodies) are produced by which of the following? Possible Answers: B-lymphocytes, usually with input from helper T-lymphocytes Helper T-lymphocytes, usually with input from B-lymphocytes Dendritic cells Natural killer cells
Correct answer: B-lymphocytes, usually with input from helper T-lymphocytes Explanation: B-cells produce antibodies (a subset of adaptive immunity called humoral immunity). The usual sequence involves B-cell activation via interleukins from helper T-lymphocytes, which cause the B-cell to undergo mitosis, creating numerous clones that will differentiate into plasma cells (rapid antibody producers) or memory B-cells.
Immunoglobulins (also known as antibodies) can be found in which of the following tissues? Possible Answers: Only in the blood plasma and certain secretions The linings of the digestive and respiratory tracts Blood plasma, tissue fluid, and on the surface of some immune cells Only in the blood plasma
Correct answer: Blood plasma, tissue fluid, and on the surface of some immune cells Explanation: Antibodies (or immunoglobulins) are produced by B-leukocytes and plasma cells, and are a key part of humoral (having to do with bodily fluids) immunity. As such, they can be found in several of the fluids circulating or exiting the body. Some types of immunoglobulins can even cross the placenta or be secreted in breast milk to pass immunity from a mother to her child.
Which of the following statements is a commonality between T-cell receptors and B-cell receptors? Possible Answers: Both receptors consist of both heavy chains and two light chains to form the antigen binding domain Both receptors have variable regions that form an antigen binding site Both receptors recognize antigens in conjunction with major histocompatibility complex (MHC) proteins Both receptors are able to bind to intact antigens
Correct answer: Both receptors have variable regions that form an antigen binding site Explanation: T-cells generally serve to recognize antigens and escort them to B-cells to elicit a response (helper T-cells) or to recognize antibodies bound to infected cells (cytotoxic T-cells). B-cells, in contrast, will directly secrete antibodies against the antigen after binding of the antigen at the membrane. Both types of cells have receptors that can bind to antigens, allowing for recognition and communication. Other commonalities include the presence of a transmembrane domain and the presence of a variable region, which will allow for specificity in antigen binding. The similarities are mainly structural, and the receptors have many functional differences. T-cell receptors will only bind fragments of antigens, while B-cell receptors will bind full molecules. Only T-cell receptors will interact with major histocompatibility complexes (MHC). Though the structure of both receptors types is determined by peptide chains, B-cells use heavy and light chains, while T-cells use alpha and beta chains.
Which cell is responsible for stimulating differentiation of B-lymphocytes into specialized plasma cells? Possible Answers: Cytotoxic T-cells Antibodies Memory B-cells Helper T-cells
Correct answer: Helper T-cells Explanation: The differentiation of many acquired immune cells is largely dependent on helper T-cells. In the presence of a matching antigen, B-lymphocytes can be differentiated into plasma cells and memory B-cells with the assistance of helper T-cells. Memory B-cells are easily triggered if an antigen is presented during a second infection, while plasma cells are the final differentiated form of a B-cell responsible for mass-producing antibodies. Helper T-cells are also important in the activation of cytotoxic T-cells, which detect antibody-antigen complexes on cell membranes and help to destroy these tagged cells.
which of the following is not an immune cell? Possible Answers: Basophils Macrophage Keratinocytes B-cells Neutrophils
Correct answer: Keratinocytes Explanation: Keratinocytes are not immune cells. Rather, they secrete a protein called keratin which is a large proportion of the extracellular matrix and makes up hair, nails, skin, and other parts of the body. All other cells are immune cells.
Which cells of the immune system are largely responsible for phagocytosis? Possible Answers: Antibodies Macrophages B cells T helper cells
Correct answer: Macrophages Explanation: Macrophages and neutrophils are the major cells of the immune system responsible for phagocytosis. Phagocytosis means ingestion of material. Therefore these cells work as "garbage collectors" within the body. Cells destined for destruction are tagged for phagocytosis by special molecules.
Long-lived B cells that circulate the body and respond to subsequent infections are called __________. Possible Answers: IgG Immunoglobulins Memory cells Plasma cells Macrophages
Correct answer: Memory cells Explanation: Memory B cells circulate the body and are ready to respond to subsequent infections while plasma cells generate many antibodies to a current infect. "Immunoglobulins" refers to both the B cell receptor and to the excreted form of these proteins (known as antibodies). IgG is a class of immunoglobulins (along with IgA, IgE, IgD, and IgM). Finally, macrophages are cells that engulf non-self (and often antibody-bound) cells and communicate with T cells to promote B cell proliferation.
What type of cell creates free antibodies that then circulate in the bloodstream? Possible Answers: Monocytes Memory B-cells Cytotoxic T-cells Helper T-cells Plasma cells
Correct answer: Plasma cells Explanation: Humoral, or B-cell, immunity is associated with the formation of antibodies. Plasma cells are B-lymphocytes that have been differentiated with the help of a helper T-cell. They release antibodies, which are created to respond to a specific pathogen in the body. Cytotoxic T-cells are also activates by help T-cells, but are involved in cell-mediated immunity rather than humoral immunity. They target infected cells based on antibody tagging. Monocytes are a part of the innate immune response and are not involved in antibody interactions. They primarily differentiate into macrophages, which engage in phagocytosis of pathogens.
Which of the following cells is not part of the innate immune response? Possible Answers: Neutrophils Macrophages Eosinophils Plasma cells
Correct answer: Plasma cells Explanation: Innate immunity is a generalized form of protection against pathogens in the body. The cells of innate immunity generally attack all types of invasive agents and do not interact with antibody production. Neutrophils, eosinophils, and macrophages are all generalized leukocytes that are present in the body. Neutrophils, basophils, and eosinophils are the primary granulocytes, all of which are involved in innate immunity. Macrophages are differentiated monocytes, capable of phagocytosis against non-specific invaders. Plasma cells are differentiated B-lymphocytes. They release antibodies into the bloodstream that are specific for a given pathogen. As a result, plasma cells are only present following a specific infection. They are a crucial part of the adaptive immune response, but are not involved in innate immunity.
Embryonic stem cells can go on to form any of the three germ layers (endoderm, mesoderm and ectoderm). How can they be defined? Possible Answers: None of the other answers Progenitor cells Multipotent Pluripotent Totipotent
Correct answer: Pluripotent Explanation: The ability to form any of the three germ layers is known as pluripotency. Totipotent cells, such as the zygote, are able to form an entire organism, multipotent cells are able to form any cell within the same germ layer lineage, and progenitor cells are cells closer to differentiation, often found in adult organisms.
Which of the following statements describes the primary role of major histocompatibility complex (MHC) class I molecules? Possible Answers: Presentation of short peptide fragments that are recognized by cytotoxic T-cells Activation of the complement cascade Stimulate production of interferon gamma Presentation of short peptide fragments to MHC class II molecules
Correct answer: Presentation of short peptide fragments that are recognized by cytotoxic T-cells Explanation: Major histocompatibility complex (MHC) class I molecules are found on virtually all cells in the body. They function in routine immune monitoring through presentation of short peptide fragments derived from degradation of intracellular proteins contained within the cell. The T-cell receptor on cytotoxic T-cells interacts with MHC class I, and if a foreign pathogen or peptide is presented, the cytotoxic T-cell becomes activated to kill infected cells. The same system also functions for detection of potential cancer cells.
Which of the following functions is NOT performed by the lymphatic system? Possible Answers: Provides additional oxygen for body tissues Elicits an immune response in the presence of an infection Returns interstitial fluid to the bloodstream Transports fat digestates and places them into the bloodstream
Correct answer: Provides additional oxygen for body tissues Explanation: The lymphatic system is responsible for removing excess fluid from the interstitium and returning it to the bloodstream. The fluid will travel through lymph nodes, which monitor for the presence of microbes in the blood. If microbes are present, the lymph nodes will mount an immune response. The lymphatic system also reroutes fat digestates from the small intestine's capillaries and drains them into the veins of the neck. Lymphatic vessels do not assist in the transfer of oxygen to body tissues.
Which of the following is a characteristic of acquired immunity? Possible Answers: Recognition of traits specific to a particular pathogen Acquired immunity is a rapid response Recognition of shared traits by a wide array of pathogens Use of basophils and mast cells to create inflammation Response is driven by phagocytic cells
Correct answer: Recognition of traits specific to a particular pathogen Explanation: Acquired, or adaptive, immunity is a second immune defense system and develops slowly after exposure to an initial infection. As a result, the immune system is "trained" and capable of recognizing many specific components or antigens from the pathogen. Acquired immunity stores the information from an initial infection in preparation for reintroduction of the pathogen; it does not immediately respond to the initial infection. Upon reinfection or exposure to a pathogen, the acquired immunity is better able to detect and defend the body. This includes the generation of antibodies that can bind a pathogen and cytotoxic T-lymphocytes that can detect and eliminate infected cells. Acquired immunity is balanced by innate immunity, which responds indiscriminately to all pathogens. Innate immunity is essential for fighting and preventing initial infections, before adaptive immunity has learned to recognize the specific pathogen present.
once an individual becomes exposed to a pathogen, the body's immune system responds faster against a second exposure to the same pathogen. Why does this occur? Possible Answers: Innate defenses are strengthened Specific lymphocytes quickly produce the proper antibodies Pathogens are changed so they are no longer harmful Stimulated memory cells quickly engulf pathogens The proper antibodies are constantly circulating in the blood
Correct answer: Specific lymphocytes quickly produce the proper antibodies Explanation: Innate defenses, such as skin and macrophages, are a primary defense against all diseases, but adaptive immunity is related to exposure to a specific disease. The ability for the body to produce specific antibodies quickly provides adaptive immunity. While some antibodies may remain in the blood after initial exposure, this small amount does not provide sufficient immunity. The specific lymphocytes that produce antibodies during a second exposure are called memory B-cells. When an antigen is presented to a memory B-cell that produces the appropriate antibody, the cell divides and differentiates into plasma cells. Plasma cells are then responsible for producing large amounts of antibodies against the specific antigen. Antibodies are cell-surface markers that attach to pathogens, signaling effector cells to rapidly destroy the pathogen. The rapid multiplication of B-cells to generate antibody to a specific threat is known as clonal selection.
Which of the following cells would not be part of the immune response when a pathogen is encountered by the body for the first time? Possible Answers: T-cells Macrophages Monocytes Neutrophils
Correct answer: T-cells Explanation: The body has a generalized group of phagocytic cells that can attack microbes that have made it past the skin. Macrophages and neutrophils are the first cells to respond to an infection. Monocytes will later migrate from the bloodstream into the body tissues and phagocytize pathogens. T-cells are part of the acquired immune system and are only present after a specific pathogen had been previously encountered in the body.
hich of the following is not a feature of toll-like receptors (TLRs)? Possible Answers: TLRs are found in innate immune cells Activation of TLRs stimulates an inflammatory response TLRs control B-cell clonal selection TLRs recognize different specific components of pathogens, such as lipopolysaccharides
Correct answer: TLRs control B-cell clonal selection Explanation: Toll-like receptors (TLRs) are a family of receptors found within innate immune antigen-presenting cells such as dendritic cells, monocytes, and macrophages. These receptors recognize specific elements of various infectious agents such as lipopolysaccharides, DNA, and RNA. Binding and activation of these receptors stimulates inflammatory responses and CD4/CD8 T-cell responses to drive an effective immune response. TLRs do not control B-cell clonal selection, the process by which B-cells replicate to amplify the production of a certain antibody.
Which of the following correctly describes the relationship between an antigen and an antibody? Possible Answers: Antibodies attack antigens and neutralize their effects Antibodies are only made once antigens enter the body Each antibody recognizes a variety of different antigens Each antigen has a number of different antibodies that will bind to it The antigen and antibody are perfectly complimentary to one another
Correct answer: The antigen and antibody are perfectly complimentary to one another Explanation: Antibodies are continuously made in the body in different shapes and forms. They are then sent into the blood stream to test for the presence of compatible antigens. Each antibody can only bind to one antigen, and each antigen can only bind to one antibody. Think of them like a codon-anticodon pair; there is only one possibility for them to form a perfectly complementary pair. Once the correct antibody binds to an antigen, they are tagged and used to stimulate production of more antibodies. The antibodies are only capable of binding and tagging the antigens. Cytotoxic T-cells are then able to recognize antibody binding patterns and actually destroy the infected cell.
What happens antibodies for a specific antigen when that antigen is presented in the body? Possible Answers: The body will attack the antibodies that are attacking the antigen The body will multiply the antibodies to the antigen The body will destroy the antibodies and uptake the antigen The body will create alternative forms of the antibody The body will make antibodies with similar structure to the antigen
Correct answer: The body will multiply the antibodies to the antigen Explanation: The immune system is very adaptive. The body has many antibodies that will each recognize different antigens. If an antibody binds to an antigen, the antibody will be copied so that the body can quickly recognize the threat if it is exposed to the antigen a second time. This process is known as the adaptive immune response. When an antigen is presented for a second time, antibodies to the antigen are released. These antibodies bind to the antigen, labelling it for attack by immune cells and preventing it from interacting the membrane proteins on the host cells.
What is the most likely mechanism a virus could use to evade the immune system that causes periodic outbreaks in an individual over a long period of time? Possible Answers: The virus manages to attack immune cells needed to control the infection The virus is continually evolving and manages to vary its antigenic signature so that it can evade detection The virus remains dormant until a stimulus, such as stress or infection with another pathogen, reactivates the virus The virus is actively causing infected cells to secrete factors that suppress the immune system
Correct answer: The virus remains dormant until a stimulus, such as stress or infection with another pathogen, reactivates the virus Explanation: Some viruses evade the immune system using a mechanism known as latency. The virus essentially becomes dormant, usually in cells such as neurons that have few major histocompatibility (MHC) class I molecules. The combination of limited to no active viral replication combined with residence in cells with few MHC lass I molecules allows the virus to evade routine immune monitoring. When conditions arise, such as fever due to infection caused by another pathogen or emotional stress, the virus can becomes reactivated and can result in an outbreak.
which of the following is not a characteristic of B-cell receptors? Possible Answers: They consist of two polypeptide chains They consist of two identical heavy chains and two identical light chains They have transmembrane domains that anchor into the B-cell plasma membrane Upon further maturation, the B-cell receptor can become a secreted molecule
Correct answer: They consist of two polypeptide chains Explanation: Each B-cell receptor is a Y-shape molecule that, upon maturation, can become a secretory form (an antibody). Each receptor is comprised of four polypeptide chains: two identical heavy chains and two identical light chains. The four chains are linked together by disulfide bridges. Both heavy and light chains consist of constant regions, as well as variable regions. The variable regions of each chain provide the specificity for antigen binding, which generates a signaling cascade within the B-cell.
Which of the following is true regarding red blood cells? Possible Answers: They produce antibodies They are made by the liver They have no nucleus They are the target of human immunodeficiency virus (HIV) They live for about 1 month
Correct answer: They have no nucleus Explanation: Red blood cells are made in the bone marrow, and live for about 3-4 months. They are enucleated (lacking a nucleus), which makes more space available for hemoglobin molecules, which function to carry oxygen to the tissues. HIV infects T-helper cells, which are white blood cells, not red blood cells. Thus, the name makes sense since the virus infects cells of the immune system (white blood cells) and causes immunodeficiency. The liver and spleen play roles in recycling the red blood cells once they have carried out their function for about 120 days.
The lymphatic system is involved in all except which of the following processes? Possible Answers: Maintain blood volume by reducing fluid loss to the extracellular compartment It is a crucial component of the immune system Transport red blood cells for destruction in the spleen Transport fats and fat-soluble vitamins that are absorbed via the digestive tract
Correct answer: Transport red blood cells for destruction in the spleen Explanation: Red blood cells generally do not leave the circulatory system; thus there are very few opportunities for lymphatic vessels to pick up red blood cells in the extracellular space. The lymphatic system plays a key role in transporting immune cells, such as lymphocytes, throughout the body. When fats are emulsified and digested in the small intestine, they are transported into the lymph rather than into the blood. When plasma and fluids leak out of capillaries, the lymphatic system is responsible for collecting and returning these fluids to circulation. A fault in this function of the lymphatic system results in edema.
The chemical reaction in the immune system that protects the body from pathogens is a result of antibodies created by which of the following? Possible Answers: Red blood cells Platelets Glandular cells White blood cells Adipose cells
Correct answer: White blood cells Explanation: White blood cells is the correct answer here. After pathogen has entered the body, the antibodies to combat it are created by B cells that are a part of the white blood cells in the human body.
The spleen is an organ of the __________. Possible Answers: digestive system circulatory system respiratory system immune system
Correct answer: immune system Explanation: The spleen plays a key role in the immune system as one of the blood filtration centers of the body. It is also involved as a lymphatic organ, allowing filtrates from the blood to be distributed to the body via lymph.
Metastasis is __________. Possible Answers: the spread of the cells produced during mitosis the spread of cancer cells beyond their site of origin the asexual reproduction of cells the spread of the cells produced during meiosis
Correct answer: the spread of cancer cells beyond their site of origin Explanation: Metastasis is the proliferation of cancer cells into new tissues. Cancer usually metastasizes through the circulatory or lymphatic systems, and the cancerous cells take residence in other, seemingly unrelated parts of the body.
In what way do eosinophils differ from other innate immune system cells? Possible Answers: They have low phagocytic activity They secrete antibodies They produce anti-inflammatory cytokines They detect and eliminate infected host cells
Correct: They have low phagocytic activity Explanation: The granulocytes are responsible for numerous functions of innate immunity, from secreting histamine, to phagocytosis, to anti-inflammatory processes. These cells are the basophils, neutrophils, eosinophils, macrophages (monocytes), and mast cells. Eosinophils have a more limited role in innate defense than the other granulocytes. They possess only low phagocytic activity, however, they are more specialized to respond to multi-cellular pathogens, such as parasitic worms. Rather than phagocytosing an invading organism, eosinophils function by releasing an arsenal of destructive enzymes and free radicals to ward off the organism. The other granulocytes are specialized for phagocytosis of bacteria, viruses, and cellular debris.
Class 1 MHC molecules
a collection of cell surface glycoproteins encoded by a familiy of genes called the major histocompatibility complex. In humans, these glycoproteins are also known as HLA, human leukocyte antigens. Class I MHC molecules are found on all nucleated cells
Class II MHC molecules
a collection of cell surface glycoproteins encoded by a family of genes called the major histocompatibility compelx. In humans, these glycoproteins are also known as the HLA, human leukocyte antigens. Class II MHC molecules are restricted to a few specilaized cell types
Which immune cells contribute most to the humoral immune response? Possible Answers: Natural killer T cells Basophils Helper T cells B cells Phagocytes
correct answer: B cells Explanation: The humoral response refers to the antiquated term "humors", meaning body fluids, as used in ancient and medieval medicine. In response to antigen exposure, B-cells release antibodies into the extracellular fluid and throughout the body, thus eliciting a "humoral response." Although helper T-cells are responsible for activating B-cells, the humoral response is limited to B-cells because they are the ones releasing products into the body fluids.
Which leukocyte releases histamine in order to dilate blood vessels and increase blood flow to infected areas? Possible Answers: Basophils Neutrophils Plasma cells Eosinophils
correct answer: Basophils Explanation: Basophils are the least common leukocyte found in the body, but play a key role in the inflammatory response. They contain histamine, which is a potent vasodilator. Upon release, histamine will increase blood flow to infected areas. Mast cells are another immune cell that is involved in histamine release, but are generally localized to various regions of the body rather than found in circulation. Basophils, mast cells, eosinophils, and neutrophils are all considered granulocytes and are essential cells in the innate immune response. Plasma cells are differentiated B-lymphocytes that are responsible for mass-producing antibodies to a specific antigen.
Which immune cells primarily contribute to allergic reactions? Possible Answers: Mast cells Dendritic cells B-cells Phagocytes T-cells
correct answer: Mast cells Explanation: Mast cells contains secretory granules, rich in histamine and other hormonal mediators, that promote inflammation and other allergy symptoms in response to antigen exposure.
Maternal immunity to some antigens may be conveyed in-utero. This is an example of which type of immunity? Possible Answers: Artificial active immunity Immunity to viral infections Artificial passive immunity Natural active immunity Natural passive immunity
orrect answer: Natural passive immunity Explanation: Natural passive immunity is conveyed from mother to child in-utero or through colostrum in breast milk. Natural passive immunity provides temporary immunity to many diseases. Natural active immunity occurs when an individual develops a disease as a result of being exposed to a live pathogen, and acquires immunity to that pathogen as a result. Artificial active immunity is acquired as a result of intentional exposure to a pathogen, as in a vaccination. Artificial passive immunity occurs when antibodies are transferred from one person to another. Immediate short-term protection may be conveyed to immune-compromised patients, such as chemotherapy recipients, by this mean. Essentially, active immunity requires exposure to a live pathogen; passive immunity does not (only antibodies). Artificial immunity requires intervention in the form of a vaccine or medical care, while natural immunity occurs unintentionally through exposure.
