Question

1- Cytotoxic T cells recognize and kill host cells infected by viruses. They recognize these cells by the foreign antigen displayed on the host cell’s:

               MHC I molecules

               MHCII molecules

               toll like receptors

2- Clonal selection:

               can be caused by vaccinations

               explains why the immune system responds stronger to a second infection than a first

               results in antibody specificity following a bacterial infection

               all of the above

3- Which of the following describes innate immunity?

               It is a response to a specific pathogen and is the basis for the use of vaccines.

               It is the basis for the use of vaccines.

               It is a response to a specific pathogen.

               It reacts to a wide variety of pathogens.

4- Specificity is a feature of which of the following?

               neither the innate nor the adaptive immune systems

               both the innate and adaptive immune systems

               the adaptive immune system

               the innate immune system

5- The complement system refers to:

               proteins that are activated when histamine levels increase.

               proteins circulating in the blood that are activated by antibodies or molecules on pathogens.

               proteins circulating in the blood that are activated by opsonization.

               proteins present on macrophages that recognize foreign proteins.

6- The adaptive immune system does NOT include:

               B cells.

               mast cells.

               plasma cells.

               memory cells.

               T cells.

7- Genomic rearrangement in B cells occurs:

               during clonal selection after antigen binding.

               in the bone marrow when B cells divide and produce daughter B cells.

               after clonal selection when antibodies are required for immune response.

               in the gamete-producing cells of an individual.

8- Which of the following statements is/are TRUE regarding the secondary immune response? (Select all that apply.)    

               It occurs faster than the primary immune response.

               It occurs more slowly than the primary immune response.

               It produces fewer antibodies than the primary immune response.

               It produces more antibodies than the primary immune response.

9- Sometimes an organ can be replaced by moving it from one part of the body to another. This can be done, for example, to replace damaged skin or joints. In these cases:

               antigens would be generated against the transplanted organ.

               antibodies would be generated against the transplanted organ.

               immunosuppressant drugs would be required to prevent transplant rejection.

               rejection of the transplanted organ would not be expected.

               rejection of the transplanted organ would still be expected.

10- A woman goes to the doctor and is diagnosed with rheumatoid arthritis. What factors led to her developing this disease? (Select all that apply.)

               Some of her T cells were not negatively selected.

               Some of her T cells are recognizing and responding to herself antigens.

               Some of her T cells were not positively selected.

               Some of her T cells are not recognizing and associating with her MHC proteins.

11- Cells with class I MHC proteins that contain a foreign antigen will be destroyed after:      

               releasing histamine.

               being bound by helper T cells.

               stimulating the MAC.

               being bound by cytotoxic T cells.

12- Virus-infected cells are detected and destroyed by which cell-mediated immune response?

               macrophages

               cytotoxic T cells

               helper T cells

               B cells

13- Which of the following is required to activate a helper T cell, which in turn can stimulate antibody production by B cells?

               an antigen

               a major histocompatibility complex

               an antigen and a major histocompatibility complex protein

               an antibody and a major histocompatibility complex protein

               an antibody

14- The secretion of cytokines is a function of _____ cells.

               plasma

               cytotoxic T

               killer T

               helper T

Answer 1

1) Cytotoxic T cells recognize and kill host cells infected by viruses. They recognize these cells by the foreign antigen displayed on the host cell’s:

Answer is: MHC I molecules

Explanation:

Cytotoxic T cells destroys cells which are based on the peptides they displayed on MHC class I surface.
A cytotoxic T cell expresses T-cell receptors that can recognize specific antigen which are bound to class I MHC molecules and can be recognized by the T cell.


2) Clonal selection:

Answer is: all of the above

Explanation:

Clonal selection explains immunological memory rapid response when there is second exposure to an antigen. Immunological memory is the because of artificial immunity which means from vaccinations.

After exposure to antigen, body make less antibody, when there is second exposure to antigen then it produces fast response. Thus, binding of antibody to antigen increases in the second response. This memory of antigen is basis for vaccination.

Clonal selection may explains why the immune system responds stronger to a second infection than a first because of increased binding affinity from clonal expansion.


3) Which of the following describes innate immunity?

Answer is: It reacts to a wide variety of pathogens.

Explanation:

Innate immunity is the first line of defence and thus, it is non-specific which means there are same responses for all pathogens.

Adaptive immunity is the second line of defence that develops memory of infections that are specific to the pathogen.


4) Specificity is a feature of which of the following?

Answer is: the adaptive immune system

Explanation:

Innate immunity is the first line of defence and thus, it is non-specific which means there are same responses for all pathogens.

Adaptive immunity is the second line of defence that develops memory of infections that are specific to the pathogen.


5) The complement system refers to:

Answer is: proteins circulating in the blood that are activated by antibodies or molecules on pathogens.

Explanation:

The complement system refers to a series of proteins that are circulating in the blood and tissue fluids.

Complement system can be activated by pathogens directly or by pathogen-bound antibody indirectly.


6) Answer is: mast cells

Explanation:

The adaptive immune system cells are B cells and T cells. B cells derived from the bone marrow, that producea antibodies. T cells mature in the thymus.

Mast cells are innate immunity