viruses and immune system mastering bio

Which of the following is characteristic of the lytic cycle? Many bacterial cells containing viral DNA are produced. The viral genome replicates without destroying the host. Viral DNA is incorporated into the host genome. A large number of phages are released at a time. The virus-host relationship usually lasts for generations.

A large number of phages are released at a time.

Which of the following events stimulates the production of viral particles in a host cell? Processing of viral envelope proteins at the Golgi. Activation of the host cell by cytokines, growth factors, or antigens. Assembly of viral proteins and mRNA molecules. Low-level transcription of viral DNA.

Activation of the host cell by cytokines, growth factors, or antigens.

Clonal selection is an explanation for how A) V, J, C gene segments are rearranged B) an antigen can provoke production of high levels of specific antibodies C) a single type of stem cell produce both red blood cells and white bloods cells D) macrophages can recognize specific T cells and B cells E) HIV can disrupt the immune system

B

Immunological memory accounts for A) the observation that some strains of the pathogen that causes dengue fever cause worse disease that others B) the ability of a helper T cell to signal B cells via cytokines C) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased D) the ability of the immune system to present antigen fragments in association with MHC antigens E) the human body's ability to distinguish

C

The MHC is important in T cell's ability to A) recognize differences among types of cancer B)recognize specific parasitic pathogens C)identity specific bacterial pathogens D) distinguish self from nonself E) identify specific viruses

D

An epitope is A) a protein protruding from the surface of B cells B) a mirror image of an antigen C) part of the interferons that penetrate foreign cells D) two structurally similar antibodies dissolved in the blood plasma E) that part of an antigen that actually binds to an antigen receptor

E

B cells have antigen receptors that bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells. T cells have antigen receptors that A) are active only in lymph nodes B) bind only to antigens present on the surface of the invading/foreign cellls C) Bind only to freely dissolved antigens in the plasma D) bind to antigens that are either freely dissolved or present on the surface or foreign or invading foreign cellds E) binds to antigen fragments presented on major histocompatibility complexes by host cells

E

How does HIV cause disease? HIV kills cells that defend the body against disease. HIV mutates host DNA and causes cancer. HIV kills red blood cells. HIV kills brain cells.

HIV kills cells that defend the body against disease.

Which enzyme inserts viral DNA into the host's chromosomal DNA? Integrase DNA polymerase Reverse transcriptase Protease

Integrase

Which replicative cycle describes a virus that can integrate its genome into the host cell's genome? Viral Lytic Lysogenic Mutagenic

Lysogenic A lysogenic virus can integrate its genome into the host cell's genome and be duplicated by the host cell's replication machinery.

Tissues are immunogically "typed" before an organ transplant to make sure that the donor and recipient match as closely as possible in their _____. histamines B cells antibodies T cells MHC (major histocompatibility complex) proteins

MHC (major histocompatibility complex) proteins

Which of the following statements describes the lysogenic cycle of lambda (λ) phage? After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA. Most of the prophage genes are activated by the product of a particular prophage gene. Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic. The phage genome replicates along with the host genome.

The phage genome replicates along with the host genome.

How does HIV bind to a host cell? The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane. CD4 binds to a co-receptor on the cell surface. CD4 binds to the viral capsid on the cell surface. The viral envelope proteins interact with gp120 on the host-cell membrane.

The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane.

How do enveloped viruses differ from nonenveloped viruses? They have a membrane-like outer covering. They have a protein coat. They are too small to see with a light microscope. They have a capsid.

They have a membrane-like outer covering.

Extracellular pathogens such as viruses and bacteria in body fluids are attacked by _____. complement proteins helper T cells antibodies from plasma cells antigens cytotoxic T cells

antibodies from plasma cells

The nucleic acid of a virus particle is enclosed in a protein coat. What is it called? envelope genome capsid nuclear envelope nucleoid

capsid

Which of the following cells are involved in cell-mediated immunity and also respond to class I MHC molecule-antigen complexes? cytotoxic T cells helper T cells natural killer cells macrophages B cells

cytotoxic T cells

Mammals have Toll-like receptors (TLRs) that can recognize a kind of macromolecule that is absent from vertebrates but present in/on certain groups of pathogens, including viral phospholipids. lipopolysaccharides. glycoproteins. double-stranded RNA. double-stranded DNA.

double-stranded RNA.

True or false? The human immunodeficiency virus (HIV) uses reverse transcriptase to make double-stranded RNA copies of its DNA genome. True False

false

A cell type that interacts with both the humoral and cell-mediated immune pathways is a CD8 cell. natural killer cell. helper T cell. cytotoxic T cell. plasma cell.

helper T cell.

B cells interacting with helper T cells are stimulated to differentiate when helper T cells release cytokines. helper T cells present the class II MHC molecule-antigen complex on their surface. B cells produce IgE antibodies. B cells release cytokines. helper T cells differentiate into cytotoxic T cells.

helper T cells release cytokines.

An inflammation-causing signal released by mast cells at the site of an infection is mucus. histamine. lymphatic fluid. sodium ions. an interferon

histamine.

Acidity in human sweat is an example of _____. cell-mediated immune responses adaptive immunity innate immunity acquired immunity

innate immunity

Macrophages are _____. the best defense against parasites cells that induce the lysis of virus-infected body cells antigen-presenting cells that originate from neutrophils large, phagocytic cells that can leave the circulation and enter the tissues of the body short-lived cells that self-destruct soon after engulfing foreign invaders

large, phagocytic cells that can leave the circulation and enter the tissues of the body

Secondary immune responses upon a second exposure to a pathogen are due to the activation of stem cells. B cells. memory cells. T cells. macrophages.

memory cells.

Engulfing-phagocytic cells of innate immunity include all of the following except natural killer cells. dendritic cells. macrophages. neutrophils.

natural killer cells.

This type of immunity is present only when a newborn infant is being fed by actively nursing its mother and ends when nursing ends. passive immunity active immunity cell-mediated immunity innate immunity adaptive immunity

passive immunity

Adaptive immunity depends on pathogen-specific recognition. having exhausted all options for innate immunity responses. traits common to groups of pathogens. plants being exposed to new pathogens. maternal provision of antibodies to offspring.

pathogen-specific recognition.

What do we call a virus that attacks a bacterium? prion viroid phage paramyxovirus retrovirus

phage

The fact that there are about a million different antigen receptors possible in human B cells is based on _____. constant changes in the splicing pattern of receptor genes after the differentiation of the B cell having one million different immunoglobulin genes temporary changes in the ways that RNA is spliced in the B cells recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells the capacity of memory cells to produce antibodies

recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells

HIV uses which of the following processes to synthesize a DNA strand using its RNA genome as a template? conjugation reverse translation reverse transcription transcription translation

reverse transcription

Viral DNA makes mRNA by the process of _____. . replication infection translation lysis transcription

transcription

In the lysogenic cycle _____. host DNA is destroyed and viral DNA is replicated a bacterium replicates without passing viral DNA to its daughter cells viral DNA is destroyed and host DNA is replicated a bacterium divides once before the lytic cycle is initiated viral DNA is replicated along with host DNA

viral DNA is replicated along with host DNA

The activation of helper T cells is likely when a cytotoxic T cell releases cytokines. when natural killer (NK) cells come in contact with a tumor cell. when B cells respond to T-independent antigens. when an antigen is displayed by a dendritic cell. in the bone marrow during the self-tolerance test.

when an antigen is displayed by a dendritic cell.