BIO308_Exam4_QuestionPack

HIV is somewhat different, however, in that the viral genome integrates into the host cell chromosome and survives as a _________________ during its latent period.

provirus

HIV core contains gp120 and gp41. T/F

False

Fragments of foreign proteins are antibodies T/F

False They are antigens

T-dependent antigen triggering of a B cell requires previous antigen presentation to the TH2 by a dendritic cell; this presentation must be in conjunction with a MHC class _____ molecule.

II Explanation T-dependent antigen triggering requires previous exposure to antigen on MHC class II molecules before B cell activation can occur.

Chickenpox virus follows a similar life cycle, exhibiting a latent period that can last for decades and where reactivation of the virus leads to the disease known as ___________________.

shingles

B cells, like T cells, require two signals:

signal 1: antigen-BCR interaction signal 2: T-cell cytokines

Antigens that elicit a response with the aid of T cells are

T-dependent antigens.

B cell activation can occur through

T-dependent or T-independent antigen triggering.

A few specific antigens can trigger B cells into antibody production without T-cell cooperation

T-independent antigens their stimulation of B cells is known as T-independent antigen triggering.

A T-helper cell must become activated before it can stimulate a B cell to produce antibody. T/F

True

Cytotoxic T cells produce cytotoxins that cause apoptosis of infected cells. T/F

True

Self proteins of infected cells are not recognized by cytotoxic T cells. T/F

True

T dependent antigens are usually protein in nature. T/F

True

Viral and self-proteins are examples of proteins produced inside of the cell T/F

True

When viral DNA is integrated into the host cell chromosome, it is called proviral DNA or a provirus. T/F

True

If a strain of Neisseria gonorrhoeae is genetically altered such that it no longer has pili, predict how this might affect its virulence. a. It will be less able to establish infection because it won't be able to adhere to host tissue. b. It will be less able to establish infection because it won't be able to survive inside phagocytes. c. It will be less able to establish infection because it will be more susceptible to host factors such as complement. d. It will be better able to establish infection and will be more resistant to antibiotics.

a. It will be less able to establish infection because it won't be able to adhere to host tissue.

Which of the following statements is true about clonal selection of lymphocytes? a. Once a lymphocyte has been released from its primary development site and is exposed to its specific antigen, it proliferates to form a clone (a population of identical cells derived from a single parent cell). b. Some of the B and T cells in the lymphocyte pool react with self-epitopes; these self-reactive cells are allowed to develop and be released into the general circulation. c. The clonal selection theory has four components or tenets; the first is that the lymphocytes present in the lymphocyte pool can bind to only a limited range of epitopes. d. From a large, diverse B-cell pool, specific cells are stimulated by antigens to recombine their genetic information before they reproduce and form B-cell clones containing the altered genetic information.

a. Once a lymphocyte has been released from its primary development site and is exposed to its specific antigen, it proliferates to form a clone (a population of identical cells derived from a single parent cell). Explanation From a large, diverse B-cell pool, specific cells are stimulated by antigens to reproduce and form B-cell clones containing the same genetic information; this is known as clonal selection.

In order for HIV to attach, the host cell must have _________. a. a CD4 antigen receptor and a cell specific co-receptor b. a CD8 receptor and a specific co-receptor c. a gp120 receptor d. a CD4 receptor and a nonspecific universal receptor

a. a CD4 antigen receptor and a cell specific co-receptor Explanation The replicative cycle of HIV follows that of a typical retrovirus.

A T helper cell becomes activated by a(n) ________. a. antigen presenting cell b. plasma cell c. B cell d. memory cell

a. antigen presenting cell Explanation Antigen is presented by class II MHC molecules to T-helper (TH) cells, which triggers CD41 coreceptors on the TH cell to interact with the antigen-bound MHC molecule.

The reactivated form of chickenpox is called _________. a. herpes zoster b. rubeola c. rubella d. adenovirus

a. herpes zoster

Which of the following are needed for antibody production to occur with T cell dependent antigens? a. Antigen presenting cell b. Antigen presenting cell, T helper cell, and B cell c. Antigen presenting cell and T helper cell d. B cell e. T helper cell

b. Antigen presenting cell, T helper cell, and B cell Explanation Antigen is presented by class II MHC molecules to T-helper (TH) cells, which triggers CD41 coreceptors on the TH cell to interact with the antigen-bound MHC molecule.

Foreign antigens presented on class I MHC molecules a. stimulate macrophages to respond to the antigen. b. stimulate cell destruction by activated T-cells. c. are not recognized by the T-cells and do not stimulate cell destruction. d. stimulate cell destruction by macrophages. e. stimulate other immune system cells to respond to the antigen.

b. stimulate cell destruction by activated T-cells.

T-independent Antigens examples

bacterial lipopolysaccharides and antibodies against other antibodies.

Most drugs used to slow the progress of AIDS fall into which of the following categories? a. RNA polymerase II inhibitors b. Protein synthesis inhibitors c. Reverse transcriptase and protease inhibitors d. Topoisomerase inhibitors

c. Reverse transcriptase and protease inhibitors

Infected cells ________. a. lyse T cells b. are not affected by T cells c. display peptide fragments of degraded viral proteins on their cell surface d. have class II MHC antigens on their cell surface

c. display peptide fragments of degraded viral proteins on their cell surface

Which viral receptor is involved in HIV attachment to the host cell? a. gp41 b. p24 c. gp120 d. p17

c. gp120 Explanation The replicative cycle of HIV follows that of a typical retrovirus.

Cytotoxic T cells produce ______. a. class II MHCs b. antibodies, which make holes in cell membrane of infected cells c. perforin, which makes holes in cell membrane of infected cells d. self proteins

c. perforin, which makes holes in cell membrane of infected cells Explanation Cytotoxic T lymphocytes function to destroy host cells that have been infected by intracellular pathogens, such as a virus, or have altered MHC surface proteins.

Chickenpox is caused by the __________ virus. a. coxsackievirus B b. rubella c. varicella d. rubeola

c. varicella

Cytotoxic T cells recognize ________. a. receptors on B cells b. fragments of self proteins of infected cells c. viral antigens and class I MHC d. viral antigens and class II MHC

c. viral antigens and class I MHC

B cells that are specific for a given epitope on an antigen cannot develop into plasma cells that secrete antibody without

collaboration of T-helper cells.

Which body defense is neutralized by the type III secretion system of Yersinia pestis? a. Complement b. Antibodies c. Cytotoxic T cells d. Phagocytes e. TH cells

d. Phagocytes

Protease enzyme _________. Multiple Choice a.helps the virus attach to the host cell b. integrates viral DNA into host genome c. makes DNA from single-stranded RNA d. cleaves poly-protein into individual functional viral proteins

d. cleaves poly-protein into individual functional viral proteins Explanation The replicative cycle of HIV follows that of a typical retrovirus.

An antigen presenting cell presents antigen to a T helper cell ________. a. inside a vesicle b. on its surface on a class I MHC c. on its surface attached to an antibody d. on its surface on a class II MHC

d. on its surface on a class II MHC

Once there, the viral ____________ will remain in a latent state for perhaps years.

genome

The _________ regions of antibodies have different amino acid sequences, and these regions fold together to form the antigen-binding sites.

variable Explanation The variable regions of antibodies have different amino acid sequences, and these regions fold together to form the antigen-binding sites.

Lymphocyte clonal expansion occurs

when a single clone becomes activated by a specific antigen.

Latent viruses, such as herpesvirus, chickenpox, and HIV, exhibit a ____________ viral life cycle.

lysogenic

During a subsequent ___________ event, often related to stress, the virus becomes reactivated and migrates back down the original neuron through which it traveled causing new ____________ to develop.

1. induction 2. lesions

Formation of Turbercules in Sequence:

1. mycobacteria are engulfed by alveolar macrophage 2. mycobacteria proliferate within the infected macrophage. Additional immune cells arrive and macrophage begin to become foamy. 3. a fibrous capsule surrounds the macrophage. 4. infected macrophage lyse releasing mycobacteria and create caseous necrosis. 5. tubercule ruptures releasing mycobacteria.

Herpesvirus for instance will cause lesions on the skin during _________ infection, and then the virus may travel down ____________ neurons to spinal ganglia.

1. primary 2. sensory

The processing of proteins produced within the cell begins when

1. proteins are broken into fragments 2. transported to the rough endoplasmic reticulum 3. combined with class I MHCs 4. then move to the Golgi apparatus, and finally to the plasma membrane. Explanation Class I and class II molecules inform the immune system of the presence of nonself by binding and presenting foreign peptides.

The processing of proteins originating outside of the cell begins when

1. proteins are broken into fragments within a vesicle 2. fuses with a Golgi vesicle containing class II MHCs, 3. complex is transported to the plasma membrane.

The provirus is replicated and passed on to numerous CD4+ cells during this time; when reactivated, these cells are killed and the patient in most cases develops ______________ over time.

AIDS

Interactions with the T cell cause the B cell to proliferate and differentiate into a ___________________which starts producing antibodies.

plasma cell

B Cell

B cell activation is a multistep process usually requiring interaction with T-helper cells.

Which of the following statements is correct about antigen presentation by class I and class II MHC molecules? A. An antigen-presenting cell (APC), such as a macrophage, dendritic cell, or B cell, takes in the MHC molecule by receptor-mediated endocytosis or phagocytosis and produces MHC fragments by digestion in the phagolysosome. B. The class I MHC molecule is presented on the surface together with its endogenous antigen, enabling the host cell to present the antigen to a subset of T cells known as cytotoxic T lymphocytes. C. Class I MHC molecules bind to fragments that initially come from antigens outside the cell, thus they undergo exogenous antigen processing. D. Class II MHC molecules bind to fragments that initially come from antigens outside the cell, thus they undergo endogenous antigen processing.

B. The class I MHC molecule is presented on the surface together with its endogenous antigen, enabling the host cell to present the antigen to a subset of T cells known as cytotoxic T lymphocytes. Explanation Class I and class II molecules inform the immune system of the presence of nonself by binding and presenting foreign peptides; these molecules differ in the types of antigens they present.