BIOL 275 Exam 3 Practice 27 Questions with Verified Answers
Which is true of lysogenized cells?
A) They are immune to any further infection by any
... [Show More] virus.
B) They are immune to infection by the same virus.
C) They may have new properties AND they respond to infection with the SOS response.
D) They respond to infection with the SOS response.
E) They are immune to infection by the same virus AND may have new pr
operties. - CORRECT ANSWER E) They are immune to infection by the same virus AND may have new pr
operties.
The nucleocapsid is composed of
A) DNA and RNA and protein.
B) DNA or RNA, and protein.
C) protein located in the nucleus.
D) nucleic acid in the ribosome.
E) DNA or RNA, lipid, and protein. - CORRECT ANSWER B) DNA or RNA, and protein.
The terms helical, icosahedral, and complex refer to
A) viral life cycles.
B) forms of nucleic acid.
C) types of viral envelopes.
D) shapes of viruses.
E) types of bacteriophages. - CORRECT ANSWER D) shapes of viruses.
Diseases of short duration frequently followed by long-term immunity are referred to as
A) intermittent infections.
B) chronic infections.
C) acute infections.
D) persistent infections.
E) nonacute infections. - CORRECT ANSWER C) acute infections.
Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is an example
A) antigenic shift.
B) hemagglutination.
C) genetic reassortment.
D) antigenic drift.
E) mutagenesis. - CORRECT ANSWER A) antigenic shift.
Plant viruses enter the host plant via
A) wound sites.
B) specific receptors.
C) nonspecific receptors.
D) seeds.
E) endocytosis. - CORRECT ANSWER A) wound sites.
Which of the following is NOT true of prions?
A) Prions replicate by converting normal host prion proteins into abnormal prion proteins.
B) Prions responsible for "mad cow disease" can cause a similar disease in humans.
C) Prions can be transmitted by consumption of dried food or cooked food.
D) Prions that cause spongiform encephalopathies have a different amino acid sequence from PrPc.
E) All of the answer choices are correct. - CORRECT ANSWER D) Prions that cause spongiform encephalopathies have a different amino acid sequence from PrPc.
Please select the TRUE statement regarding bacteriophage life cycles.
A) Temperate phages lyse their host cells, whereas lytic phages either lyse their host or integrate their DNA into the host cell's genome.
B) Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome.
C) In the bacteriophage life cycle, the entire virus enters the host bacterial cell through a hole in the cell wall.
D) Phage particles seek out their bacterial hosts by means of chemotaxis and then attach to random receptors on the host's cell wall.
E) The burst size is the number of bacterial cells that are lysed as a result of being infected by a bacteriophage such as T4. - CORRECT ANSWER B) Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome.
To give more information on virus replication strategies, you explain to your friend the difference between a DNA virus and a RNA virus in terms of replication. You tell him that
A) RNA virus replication always requires a virally encoded RNA polymerase that is an RNA-dependent RNA polymerase; this enzyme uses an RNA template to synthesize a new strand of RNA. DNA viruses use DNA-dependent DNA polymerase in replication.
B) RNA virus replication always requires a virally encoded DNA polymerase, that is an RNA-dependent DNA polymerase; this enzyme uses a DNA template to synthesize a new strand of RNA. DNA viruses use DNA-dependent DNA polymerase in replication.
C) RNA viruses always encode an enzyme called reverse transcriptase, which is an RNA-dependent DNA polymerase that synthesizes DNA from an RNA template. DNA viruses use DNA-dependent RNA polymerase in replication.
D) DNA viruses replicate their genome by means of - CORRECT ANSWER A) RNA virus replication always requires a virally encoded RNA polymerase that is an RNA-dependent RNA polymerase; this enzyme uses an RNA template to synthesize a new strand of RNA. DNA viruses use DNA-dependent DNA polymerase in replication.
Which is not a component of innate immunity?
A) Skin
B) Antibody
C) Inflammation
D) Fever
E) Mucus membranes - CORRECT ANSWER B) Antibody
Which statement about skin and mucous membranes is NOT correct?
A) They are the first line of innate immunity.
B) They are the first line of adaptive immunity.
C) They act as physical barriers to infection.
D) They contain antimicrobial secretions.
E) They separate us from our environment. - CORRECT ANSWER B) They are the first line of adaptive immunity.
In humans, the stem cells from which all blood cells arise are found in the
A) peripheral circulation.
B) bone marrow.
C) lymphatic vessels.
D) lymph nodes.
E) spleen. - CORRECT ANSWER B) bone marrow.
The cells responsible for adaptive immunity are the
A) lymphocytes.
B) monocytes.
C) eosinophils.
D) neutrophils.
E) leukocytes. - CORRECT ANSWER A) lymphocytes.
The complement pathway that is activated by mannan-binding protein is the
A) classical pathway.
B) alternative pathway.
C) C3 pathway.
D) lectin pathway.
E) properdin pathway. - CORRECT ANSWER D) lectin pathway.
Interferons function to make cells
A) prevent viral replication.
B) lyse when exposed to virus.
C) non-motile when infected with virus.
D) resistant to phagocytosis.
E) form endospores. - CORRECT ANSWER A) prevent viral replication.
What two functions do phagocytes serve in immune responses?
A) Production of antibodies AND engulfment/destruction of foreign cells.
B) Engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader.
C) Alerting the other cells of the immune system to an invader AND serving as a physical barrier against microbial invasion.
D) Production of antibodies AND serving as a physical barrier against microbial invasion.
E) Alerting the other cells of the immune system to an invader AND production of antibodies. - CORRECT ANSWER B) Engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader.
How are macrophages and neutrophils similar, and how are they different?
A) Macrophages and neutrophils both circulate in the blood. Macrophages are phagocytic cells while neutrophils are granulocytes but not phagocytes.
B) Macrophages and neutrophils are both phagocytic cells. Macrophages reside in the tissues while neutrophils typically circulate in the blood.
C) Macrophages and neutrophils are both abundant cell types in tissues. Macrophages are phagocytic cells while neutrophils are not.
D) Macrophages and neutrophils are both phagocytic cells. Macrophages are granulocytes while neutrophils are effector cells.
E) Macrophages and neutrophils are both leukocytes. Macrophages are granulocytes and neutrophils are lymphocytes. - CORRECT ANSWER B) Macrophages and neutrophils are both phagocytic cells. Macrophages reside in the tissues while neutrophils typically circulate in the blood.
Fever allows the body to fight microbial invaders by which of the following mechanisms?
A) Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.
B) A moderate fever reduces the inflammatory response but stimulates phagocytic activity in neutrophils and eosinophils.
C) Fever increases the inflammatory response, but reduces the production of interferons unless the invader is a dsRNA virus.
D) Fever increases the multiplication of lymphocytes and enhances the release of substances that attract basophils that then engulf the microbial invader.
E) Fever plays all of these roles in the body. - CORRECT ANSWER A) Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.
Antibodies are made by
A) red blood cells.
B) macrophages.
C) B cells/plasma cells.
D) T cells.
E) all leukocytes. - CORRECT ANSWER C) B cells/plasma cells.
Epitopes
A) are parts of the antibody molecule.
B) are T cell receptors.
C) are parts of an antigen recognized by an antibody.
D) are B cell receptors.
E) are parts of an antibody recognized by an antigen. - CORRECT ANSWER C) are parts of an antigen recognized by an antibody.
The humoral immune response is delivered by
A) antibodies.
B) T cells only.
C) lymphokines.
D) antigens.
E) antibodies AND lymphokines. - CORRECT ANSWER A) antibodies.
Which class of antibody accounts for most of the circulating antibodies?
A) IgA
B) IgD
C) IgG
D) IgE
E) IgM - CORRECT ANSWER C) IgG
Which is the first antibody class made during the primary response to an antigen?
A) IgA
B) IgM
C) IgG
D) IgE
E) IgD - CORRECT ANSWER B) IgM
T cells and B cells are produced in the
A) bone marrow.
B) thymus.
C) Peyer's patches.
D) nervous tissue.
E) appendix. - CORRECT ANSWER A) bone marrow.
Antigens may be processed for presentation by
A. macrophages.
B. dendritic cells.
C. erythrocytes.
D. T cytotoxic cells
.E. macrophages AND dendritic cells. - CORRECT ANSWER E. macrophages AND dendritic cells.
Class II MHC molecules are found primarily on
A. macrophages.
B. dendritic cells.
C. erythrocytes.
D. T cytotoxic cells.
E. macrophages AND dendritic cells. - CORRECT ANSWER macrophages AND dendritic cells.
How is a T-cell receptor different from a B-cell receptor?
A) T-cell receptors must have antigen broken down inside a cell and presented to them by a major histocompatibility complex (MHC) molecule.
B) B-cell receptors must have antigen broken down inside a cell and presented to them by a major histocompatibility complex (MHC) molecule.
C) T-cell receptors are composed of four protein chains (pieces), while B-cell receptors are composed of only two chains.
D) T-cell receptors are eventually secreted into the bloodstream by activated T-cells, whereas B-cell receptors are not; they always stay with the B-cell.
E) B-cell receptors are composed of chains of amino acids, while T-cell receptors are composed of chains of carbohydrates. - CORRECT ANSWER A) T-cell receptors must have antigen broken down inside a cell and presented to them by a major histocompatibility complex (MHC) molecule. [Show Less]