Microbiology with Diseases by Taxonomy Chapter 16 Answers

Microbiology with Diseases by Taxonomy Chapter 16 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1CM
Human system is protected through the presence of both humoral and cell mediated systems

• In humoral systenl, antibodies are synthesized to eliminate the presence of pathogens in the system, through different modes.
• Presence of humoral immune system puts an end to number of pathogenic microorgamsms.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1CT
Advantage of lymphatic system to lack a pump:
Explanation
The absence of pump makes it sure that there is slow movement of lymph through the lymphatic vessels that is loaded with the lymphocytes. This increases the chances of microbes or antigens being identified as foreign lymphocytes; thus, eliciting an immune response against them. This is the main reason why an absence of pump aids in the betterment of the lymphatic system.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1L
The differences in the structure of the antibodies enable it to bind to different antigens that possess different antigenic determinants. The formation of an antigen-antibody complex is highly important in eliminating an antigen from the host system.
The parts of the immunoglobulin are listed below:

1. Antigen binding.
2. Heavy chain variable.
3. Light chain variable region.
4. Light chain constant region.
5. Heavy chain constant region.
6. Transmembrane B cell receptor.
7. Variable region.
8. Constant region.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1M

• Plasma cell is differentiated B lymphocyte against specific antigen, which would initiate the process of secreting antibodies against antigen. The plasma cell is an antibody producing cell. It is produced from the B lymphocytes and plays an important role in defense. Hence, plasma cell is matched against D. Immunoglobulin.
• Cytotoxic activity of T cell involves the usage of perforin and granzyme molecules. The perforin forms a tube like structure protruding the cell wall of the target cell, where granzyme enters and triggers apoptosis. Hence, cytotoxic T cell is matched against C.Perforin and Granzyme.
• T-helper cell synthesizes the interleukin 4 (IL-4) molecules that would differentiate T helper cells from type 2 helper T cells. The type 2 helper T cells are involved in T dependent B cell activation process. Hence, Th2 cell is matched against B. Interleukin 4.
• The dendritic cells are a part of the antigen presenting cells. The cells contain MHC class II molecules to present epitopes of antigens to lymphocytes in elimination target cell from the system. Hence, dendritic cell is matched against A. MHC II molecule.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1MC

• Antibodies cannot destroy a foreign graft, but could only aid to develop a catastrophic avalanche of other immune responses on the graft. Hence, option (a) is incorrect.
• Antibodies aids in marking the foreign antigens, entering the host system thereby enabling immune cells including the B and T lymphocytes to identify the antigen and destroy them. This makes option (b) as the right choice.
• Antibodies cannot be involved in killing any organisms or viruses. Their main aim is to mark the foreign antigen, which would then be taken care by the lymphocytes. Hence, option (c) is incorrect.
• Cytokine synthesis would not be activated through the presence of antibodies alone. It is only the antigen-antibody complex that would aid in the synthesis of cytokines that would elicit an immunological response in eliminating the antigen from the host system. Hence, option (d) is incorrect.
• Antibodies do not have any impact on T cell proliferation. Once the antigen is marked by the antibody, it is the T-helper cell that would recognize the antigen and would inturn stimulate the differentiation and multiplication of T-cytotoxic cells. Since it is an indirect action option (e) becomes incorrect.
• Antibody functions to (b) mark invading organisms for destruction.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1MTF
MHC class II molecules:
Explanation
The MHC (Major histocompatibility complex) class II molecules form an integral part of the antigen presenting cells, but not by T lymphocyte. The process is mediated through MHC class II molecule, the antigen presenting cell presents the antigen to T lymphocytes.
Thus, the given statement, “MHC class II molecules are found on T-cells” is False.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 1SA
Antigen processing is an essential prerequisite, for immune response:
Explanation
Antigen processing is prerequisite for identifying antigens that are of indigenous nature. Consider a case where antigen would be growing actively inside a host cell. In such situation, the presence of MHC class I molecules, the foreign antigens could be identified on the cell wall. The cells are processed and the antigens would be presented to T lymphocyte through MHC class II molecules. Hence, it is highly clinical that the antigen processing is highly essential for antigens of endogenous nature.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 2CT
Contraction between innate defenses with adaptive immunity:
Explanation

Microbiology with Diseases by Taxonomy Chapter 16 Answers 2M

• Administration of antitoxin in the form of antibodies, developed against specific toxin is an example of artificially acquired passive immunotherapy. Hence, artificially acquired passive immunotherapy is matched against D. Administration of antitoxin.
• The development of antibodies naturally against a specific antigen or allergen is termed naturally acquired immunity. Development of IgE antibody against the allergen pollen is one such example. Hence, naturally acquired active immunity is matched against A. Production of IgE in response to pollen.
• Injection of immunoglobulins into another host naturally without the aid of medical devices is termed naturally acquired passive immunity. The passage of antibodies from the mother’s breast milk to child is an example of this type. Hence, naturally acquired passive immunity is matched against B.Acquisition of maternal antibodies in breast milk.
• Deadly toxins when incorporated through injection (in a naïve form) without any natural infection, could elicit animmune response. Hence, artificially acquired active immunity is matched against C. Administration of tetanus toxoid.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 2MC

• The class II MHC molecules are present on the exterior of the helper-T cells; also upon binding with the antigen, it would activate the helper-T cells and not the cytotoxic-T cells. Hence, option (a) is incorrect.
• Since the class II MHC molecules are found on the outer surface of the helper-T cells. They would activate only the helper-T cells and not the cytotoxic-T cells. This makes option (b) incorrect.
• MHC class II molecules would be activated by the antigens presented to them through the antigen presenting cells like the macrophages. Antibodies do not have any role in the activation of the T cells. Hence, option (c) is incorrect.
• Though it is the T-helper cells that are being activated by the MHC class II molecules, the molecules are present on the outer surface of the helper-T cells. This makes the molecule an exogenous one. This criterion makes option (d) as incorrect.
• The MHC class II molecules are present exogenously on the helper-T cells. Once the antigen presenting cells presents antigens to these cells, the helper-T cells would be activated against that specific antigen. This would in turn activate the cytotoxic-T cell which would eliminate the antigen from the system. Hence, option (e) is the right choice.
• The right option is (e) exogenous antigens, helper T cells.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 2MTF
Apoptosis:
Explanation
Apoptosis is the term associated with destroying self-cellular components either during a viral infection or during clonal deletion. Cells undergo transformation in normal body cell into neoplastic or cancer cell that is not controlled by cell normal process. Moreover, cells escape from normal body surveillance though abnormal cell and body immune system destroys it.
Thus, the given statement, “apoptosis is the term used to describe cellular suicide” is True.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 2SA

• The vertebrate immune system shows two types of responses termed the humoral and the cell-mediated immune response. The type of response depends on the type of the antigen that evades the host. Though these two immune responses are demarcated as separate, the body uses both the mechanisms simultaneously to eliminate any pathogen. The difference lies in which type of immune response predominantly acts to eliminate a pathogen/antigen.
• Humoral immune response involved antibodies and is mediated by antigen activated B cells called plasma cells. They are specific to each type of antigen and the response takes time to be initiated. It generally takes at least 3 – 4 days for the B-cells to respond and synthesize specific antibodies against a pathogen.
• Antibodies are synthesized against circulating antigens. Therefore, they contain extracellular or exogenous antigens.
• Cell mediated immune responses involve cells like T-lymphocytes, macrophages, and neutrophils which act directly on the target cell and destroy it. They cell mediated immune system either directly recognize certain patterns of antigens on the target cells (like peptidoglycan or anionic polymers, which are unusual and are not found on the healthy self-cells) through their pattern recognition receptors; or recognize aberrant MHC (major histocompatibility complex) proteins on the cell surface; or they recognize antigens presented in context with MHC.
• Thus, cell mediated immune responses mainly aim at targeting cells infected with intracellular parasites, cells that became abnormal, or aberrant cells.
• Since pathogens can be either extracellular or intracellular, the two arms of immune responses are required to contain them effectively. The way the immune system deals with these two types of antigens is different. While cell mediated immune responses act quickly and inhibit the infecting pathogens from further multiplying, humoral immune responses come into play after a period of activation. Cell-mediated responses are less specific and thus, comparatively less efficient in containing a pathogen whereas humoral immune responses are highly specific and are efficient and effective in eliminating a pathogen.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 3CT
Benefit of requiring immune system to process antigen to body:
Explanation
Antigens are not supposed to be identified by the immune system of the host. At times, they would escape the immune system through their complex structure. In order, to make sure that the complex structure of the antigens is broken down to simpler substances. In addition, they are made available to immune system to elicit an effective immune response against the antigen that is being processed. This increases the chance of antigen being acted against by host immune system.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 3MC

• Destruction of virus infected cell is through cell mediated cytotoxicity, occurs through the cytotoxic T lymphocyte. One such activity of the cytotoxic T lymphocyte is the destruction of virus infected cells. Destruction of virus infected cells has no coincidence with the rejection of skin graft, though both skin grafts, and virus infected cell are rejected by cell mediated cytotoxicity. This proves that option (a) is incorrect.
• Tolerance is the term used to denote autoimmune diseases. Self-tolerance is highly important as the lymphocytes should not act against self-cells. Since, the cells belonging to the host would be identified through their MHC molecules, the host’s self-cells cannot be rejected. Tolerance and graft are diagonally opposite terms as graft need not necessarily contain the same MHC molecule. Hence, option (b) is incorrect.
• Antibody mediated immunity, takes time to react against a specific antigen. Though rejection of graft would also be accompanied by the action of humoral immune response it cannot be rejected outright by the action of immunoglobulin alone. This makes option (c) as the incorrect.
• Primary immune response is conferred when the antigen is inherited during the first time. Secondary immune response is one when the antigen is encountered the next time, where the memory cells attack the antigens immediately. Since, the graft is rejected in the first instance itself; option (d) may not be the right choice.
• Cell mediated immune response is the primary response through which a graft would be rejected immediately. The response is as a result of the cytotoxic activity of the T lymphocytes. Hence, option (e) is the right choice.
• Thus the right choice is (e) a cell-mediated immune response.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 3MTF
Lymphoid system includes tissue aggregates and organs composed of lymphoid tissue.
The five main cell types of lymphatic tissues are natural killer cells (NK cells), T lymphocytes, B lymphocytes, macrophages, dendritic cells, and reticular cells.

• T lymphocytes cannot recognize pathogens they require antigen presenting cells.
• B lymphocytes produce antibodies. They generate receptor diversity of immunoglobulins

T Lymphocytes are of two types based on the type of glycoprotein that is associated on their cellular surface. The lymphocyte that contains the CD8 (CD – Cluster of differentiation) molecule is cytotoxic T lymphocyte, whereas CD 4 lymphocyte is helper T lymphocyte. Thus, the statement, “lymphocytes with CD8 glycoprotein are helper T cells” is False.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 4CT
Immunological impairments that results in the following are:
Explanation

1. Class I MHC molecules are developed by nucleated cells in the body. The molecules present the processed antigens (intracellular antigens) to immune system and deficiency in synthesis of class I MHC molecule is susceptible to infection.
2. Class II MHC molecules are present on the surface of the helper-T cells. The antigen presenting cells would present the processed antigens to class II MHC molecules, which would elicit an immune response against the antigen provided. The presence of class II MHC molecule would ensure that any false activation of the immune system is put to rest, thus acting as a regulatory system.
3. T-cell receptors (TCR) are found on the surface of the T-cells that binds specifically to a particular antigen. The antigens bind to TCR on activation; thus, T-cells elicit cell mediated immune response against the antigen. Without which the host system would lack the cell mediated immune response. Similarly, T-cells and B-lymphocytes are also associated with receptors that are specific against a particular antigen. The presence of B cell receptors is highly essential in eliciting humoral immune response. Without, which the host system would lack the humoral immune response.
4. Interleukin-2 (IL-2) is the molecule that aids in the proliferation of lymphocytes after activation by an antigen, by attaching to IL-2 receptor of lymphocyte. Without the presence of receptor for IL-2 the activated lymphocytes will not undergo multiplication to form a clone of cells, effective against the antigen.
5. Interferon-? (IFM- ?) is essential in activation of cytotoxic-T lymphocytes. Activation of T lymphocytes is important in eliminating the intracellular pathogens of the host system. Any deficiency in the presence of IFN- ? molecule would retard the activation of cytotoxic T lymphocytes; thus, reducing the effect of cell mediated immunity.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 4MC
Microorganism from a normal biota would be termed an antigen, but not an auto-antigen. Hence, option (a) is incorrect.
When the host immune system elicits a response against its own body component, then the host cell is known to have become an auto-antigen. This makes option (b) as the right choice.
An artificial antigen is one where an antigen would be engineered for raising immunological response without actually giving the symptoms of the disease. Hence, option (c) is incorrect.
Carbohydrate that would be taken in as a normal food proportion cannot be considered as an antigen. There are situations where certain carbohydrates would be considered antigen, but definitely not as an auto-antigen. Hence, option (d) is incorrect.
A nucleic acid transferred from a virus is capable of destroying the host system through an infection. Prokaryotes are given immunity against such nucleic acids entering through the restriction modification system. Under such circumstances the nucleic acid would be considered only as an antigen and not as an auto-antigen. This makes option (e) incorrect. Thus the right choice is (b) a normal body component.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 4MTF
Immunoglobulins are antibodies that are secreted by B lymphocytes and immunity conferred is termed as humoral immunity. The cytotoxic T lymphocytes are directly involved in the removal of target cell.
The process is mediated by the following:

1. Direct cytotoxicity.
2. Complement mediated cytotoxicity.

However, type of helper T cell would aid in the activation of B lymphocytes, making them secrete immunoglobins, but T cell is not involved in antibodies secretion.
Thus, the statement, “cytotoxic T cells secrete immunoglobulin” is False.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 5CT
Effects of human immunodeficiency virus on humoral and cell-mediated immunity:
Explanation
The helper-T cells have control over both cell mediated and humoral immune responses. While, the former has a pathway that could be activated without the presence of helper-T cells, cell mediated cytotoxicity would be lost if the helper-T cells are destroyed, as a result of human immunodeficiency virus (HIV) infection. The virus specifically targets helper-T cells; thus, reducing overall effects of immune responses.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 5MC

• Perforins are produced by the natural killer cells, which would destroy the antigens by forming channels that would trigger apoptosis. The activity of the natural killer cells would be initiated by the antibody-antigen complex. This makes option (a) as the correct choice.
• Immunoglobulins are antibodies that are involved in their specific attachment to the antigens. Immunoglobulins form a part of the humoral immune response (or) antibody mediated immune response thus making option (b) as the incorrect choice.
• Complement activation is a part of the humoral immune response where the activated complemented system destroys the target cell through the formation of membrane attacking complex (MAK) on the whole cell antigen. The MAK forms pores on the pathogen, leads to change in the osmatic pressure balance. This makes option (c) as the incorrect choice.
• Cytokines are components, which are used by the human system in trafficking the lymphocytes to a particular location. They are indirectly involved in aiding cell mediated cytotoxicity, but are not a direct reason for it. Hence, option (d) becomes the incorrect choice.
• Interferons are cytokines that has the potential of acting both as a signal material as well as in emphasizing phagocytosis of the infected cells. Since it is an indirect factor involved in directing cell mediated cytotoxicity, option (e) becomes an incorrect choice. Thus the right choice is (a) perforin.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 5MTF
Immunity conferred to human system is mediated by two basic types. They include the following types:

• Humoral immunity
• Cell mediated immunity.

In humoral immunity, B lymphocytes are involved and in cell mediated immunity T lymphocytes are involved. B cells produce immunoglobulins or antibodies that would be circulated in the blood. Since, blood is known as humors, the type of immunity conferred through B lymphocytes is termed as humoral mediated immune response. Moreover, there is no cell to cell contact in humoral immune response. In cell mediated immunity, cytotoxic T lymphocyte would be in direct contact between T lymphocyte and target cell.
Thus, the statement, “secretion of antibodies by activated B cells is a form of cell-mediated immunity” is False.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 6CT
Person who fails to make MHC molecules occurs:
Explanation
The MHC class I molecules are required for presenting the processed intracellular pathogens. Moreover, it is only process through, which the class II MHC molecules represents antigen presenting cells to lymphocytes. Hence, without the presence of the MHC molecules the host system lacks the presence of acquired immunity. Thus, the person is prone to all infections.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 6MC
The T-lymphocytes are those that accounts for about 70-85% of the total lymphocyte population. Hence, option (a) becomes the right option.

• The B-lymphocytes are a major part of the remaining lymphocyte population. They are found circulating the blood. Since they are found in a very small quantum, option (b) becomes incorrect.
• Plasma cells are those multiplying B-lymphocytes that are ready to produce antibodies specifically against a particular antigen. Since they are only a part of the B-lymphocytes, option (c) becomes incorrect.
• Memory cells are those that act in reproducing the antibodies that have once formed against a specific antigen. Normally the memory cells would be less in quantum, and once the host system comes in contact with the same antigen again. The memory cells would produce the plasma cells that would synthesize the antibodies. This makes option (d) as the incorrect choice.
• The concentration of each and every component of the lymphocytes is predetermined and they are not found in the same concentration. This makes option (e) as the incorrect choice. Thus the right option is (a) T cells.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 7CT
Five different classes of immunoglobulins:
Explanation
Immunoglobulins are present throughout our immune system. They are found circulating through the blood. The existing immunoglobulin has different shapes and is conferred to have different functions. They are as follows:

1. Immunoglobulin M acts as antigen binding sites on B lymphocytes, due to their multivalent nature. Moreover, they are highly efficient when secreted during an immune response.
2. Immunoglobulin G is the highly synthesized immunoglobulin, also known as serum antibody. It is found secreted in the body fluids, blood, and fluids of tissues to react with antigens.
3. Immunoglobulin A is transferred from mother to fetus through placenta. The molecule is also present in tears and mucous where the molecule reacts with antigens.
4. Immunoglobulin E is the molecule that is capable of eliciting an allergic response by attaching itself to mast cells. The molecule binds to the mast cell through constant region. Thus, leaving free antigen binding site. When the antigen (during second contact) binds to the antibody, it triggers the mast cells to degranulate by enabling allergic response.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 7MC

• IgG molecules are the most found antibody in the system. The molecule is involved in antibody mediated immunity and is commonly found in circulating blood. Hence, option (a) is incorrect.
• IgM molecule is a pentamer composed of five IgG molecules. It is involved in agglutination, neutralization and in complement activation. Since these activities could only be done in the circulating blood. Hence, option (b) becomes incorrect.
• IgA constitutes about 12% of the total serum antibody. They are found lining the respiratory, gastrointestinal, urinary, and reproductive tracts. Hence, option (c) is the right choice.
• IgE act as signal molecules that attach to receptors on the eosinophil triggering the release of histamines. This makes option (d) as incorrect.
• IgD are not secreted, but are membrane bound antigen receptors on B cells. This makes option (e) as the incorrect choice. Thus the right option is (c) IgA.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 8CT
Ideal properties of materials implanted in the body are:
Explanation
Metal bone pins and plastic do not have an antigenic status that would elicit an immune response. Moreover, they are neither capable of causing any infection on their own. Since, MHC molecules can identify the biomolecules they do not elicit any immune response against the artificial devises implanted; thus, making it a safe entity.
Additionally, material that is not capable of eliciting an immune response proves to be a better article to be used in implantation. The only thing that needs to be kept in mind is that the material should not allow infection to pass through, being implanted.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 8MC

• MHC class I molecules would be found on all nucleated cells. Since, red blood cells lack nucleus they also do not possess the class IMHC molecule on them. This makes option (a) as the incorrect choice.
• Antigen presenting cells would be bearing the MHC class II molecule and not the class I molecule. This makes option (b) as the incorrect choice.
• Neutrophil being an antigen presenting cell would be bearing the MHC class II molecule and not the MHC class I molecule. This makes option (c) as the incorrect choice.
• The MHC class I molecules are present on all the nucleated cells of the host including the skin and muscles. Hence, option (d) is the right choice.
• Dendritic cells contain MHC class II molecules. They are antigen presenting cells that acts on the antigens and presents the antigen to the lymphocytes. This makes option (e) as the incorrect choice.
• Thus the right option is (d) all nucleated cells.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 9CT
The membranous and non-membranous organelle prevalent in plasma cells:
Explanation
The plasma cells are involved in secretion of antibodies in the system. They have high quantum of rough endoplasmic reticulum, owing to their function. The ribosome that forms an integral part of the endoplasmic reticulum is major non-membranous organelle present in the plasma cell. However, plasma cells are twice as the size of an inactive B-lymphocyte, primarily. This is because of their function in synthesizing antibodies based on presence of endoplasmic reticulum and Golgi complex. The endoplasmic reticulum aids in the production of immunoglobulins, while the Golgi complex would transport them across the cell membrane.
Thus, endoplasmic reticulum and Golgi complex are highly important membranous organelles in plasma cells.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 9MC

• B cells are synthesized in the bone marrow, which after maturation would be an integral part of the lymph node. Hence, option (a) becomes the right choice.
• Spleen is an organ, where the blood filters toxic and other antigenic substances. In order to tackle the antigens present in the blood, the filtered component would be tackled by the B lymphocytes through the production of immunoglobulins. Thus option (b) becomes the right choice.
• Red bone marrow is the place where the B cells originate, thus making option (c) as the right option.
• B cell is an integral part of Mucosal Associated Lymphoid Tissues (MALT) of the intestinal tract, majorly to tackle the antigens coming through food intake. Hence, option (d) becomes the right choice. Thus the right choice is (e) all of the above.

Microbiology with Diseases by Taxonomy Chapter 16 Answers 10MC

• The cytotoxic T cells would recognize the antigens presented to them through the MHC molecules. The helper T cells would enhance the effect of the established linkage between the MHC molecules, and that of the cytotoxic T cells aiding them to multiply. This makes option (a) as the right choice.
• The helper T cells are those that aid in the activation of the cytotoxic T cells when the antigens are presented through a MHC molecule. B cells are in no way associated in presenting the antigen to the T cells. This proves that option (b) is incorrect.
• Interleukin-2 that is secreted by the dendritic cells aids in the stimulation of the helper T cells to become a clone of type I T helper cells (which in turn secrete interleukin 2.) Interleukin 2 is primarily responsible for the differentiation of the T cells, and the formation of helper T cells. This makes option (c) as the incorrect choice.
• Granzyme is involved in the apoptosis of target cells through cell mediated cytotoxicity through the other molecule perforin. They are in no way associated with the presentation of the antigen to the cytotoxic T cells. This makes option (d) as the incorrect choice. Thus right option is (a) MHC proteins.