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BIO SCI 101 > Exam 3 > Flashcards

Exam 3 Flashcards

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1
Q

Why do most scientists agree that viruses are nonliving entities?

A

they are not cells

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2
Q

Isolated picornavirus virions would be expected to carry out which of the following types of metabolism?

A

not respiration or fermentation of glucose

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3
Q

‘Capsid’ of a virus refers to which of the following:

A

protein shell of a virus

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4
Q

T/F Helical and icosahedral are terms used to describe the shapes of a virus envelope.

A

false

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5
Q

T/F ‘Nucleocapsid’ of a virus refers to a viral genome.

A

False

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6
Q

What are bacteriophages?

A

viruses that kill bacteria

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7
Q

T/F After the entry step bacteriophages leave their proteinaceous particles outside the bacterial cell.

A

True

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8
Q

T/F The basic mechanism of viral multiplication is similar for all viruses.

A

True

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9
Q

Bacteriophages undergo replication by:

A

Lytic cycle and/or lysogenic cycle

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10
Q

Virulent phages are:

A

lytic

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11
Q

The order of lytic cycle is:

A

adsorption-injection of genetic material- biosynthesis-maturation- lysis and release

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12
Q

A clear area against a confluent “lawn” of bacteria is called a

A

plaque

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13
Q

Bacteriophages mediate what kind of horizontal gene transfer between bacterial cells?

A

transduction

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14
Q

The viral genome integrated into the bacterial genome is called:

A

prophage

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15
Q

During which phase of their replication the bacteriophage release lysozyme

A

maturation

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16
Q

Generalized transduction:

A

transfers a different portion of bacterial DNA each time

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17
Q

Specialized transduction:

A

transfers a specific portion of bacterial DNA

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18
Q

Acquisition of new traits (such as virulence factors) by bacterium because of viral infection is called:

A

lysogenic conversion

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19
Q

A virus’s ability to infect an animal cell depends primarily upon the

A

presence of receptor sites on the cell membrane

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20
Q

Which of the following statements about viruses is FALSE?

A

viruses use their own catabolic enzymes

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21
Q

Nucleic acid from virions of which of the following could be directly translated by host cell ribosomes after the nucleic acid enters the cytoplasm?

A

a picornavirus

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22
Q

A virus is said to have a minus sense RNA genome. This means that:

A

the viral genome is complementary to viral mRNA

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23
Q

Virions of the -sense RNA viruses must include:

A

RNA dependent polymerase

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24
Q

Genome of Herpes viruses is:

A

dsDNA

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25
Q

An example of a latent viral infection is

A

cold sores

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26
Q

Which virus has its genome separated into 8 segments?

A

influenza virus

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27
Q

Influenza virus has what type of nucleic acid in its virions?

A

negative sense RNA

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28
Q

Which of the following are infected by the largest diversity of influenza viruses?

A

birds

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29
Q

What contributes to antigenic shift in influenza viruses?

A

a segmented genome

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30
Q

Genome of HIV virus is:

A

+ssRNA

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31
Q

T/F HIV is a retrovirus.

A

True

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32
Q

Reverse transcriptase catalyzes which of the following:

A

copies RNA to make DNA

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33
Q

HIV virus infects:

A

T cells (lymphocytes)

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34
Q

Viral envelope is acquired during which of the following steps?

A

release

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35
Q

Which of the following is a ‘naked” virus (the one that does not have an envelope)

A

rhinovirus

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36
Q

A persistent infection is one in which:

A

the disease process occurs gradually over a long period

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37
Q

T/F Viroid is a complete, infectious viral particle.

A

False

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38
Q

Which of the following is correct about viroids?

A

do not encode any proteins

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39
Q

T/F Prion is an infectious protein.

A

False

40
Q

Mad-cow disease and Kuru are caused by:

A

prions

41
Q

Which of the following protect the skin and mucous membranes from infection:

A

saliva, multiple layers of cells, tears, and the cillary escalator

42
Q

A child falls and suffers a deep cut on her leg. The cut went through her skin, and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?

A

phagocytosis and inflammatory response

43
Q

Cells involved in innate immunity:

A

macrophages and neutrophils

44
Q

Macrophages are

A

phagocytic

45
Q

T/F Complement activation’ is a result of phosphorylation of complement proteins.

A

False

46
Q

Complement-mediated lysis of infected cells is achieved by:

A

formation of the MAC, which is particularly effective against Gram-negative bacteria

47
Q

Interferons are proteins (cytokines) released by some cells to fight:

A

viral infection

48
Q

Clearing of virus infected cells is accomplished by which cells?

A

Natural Killer (NK) cells

49
Q

B and T cells are involved in which immunity type?

A

adaptive immune response

50
Q

Which of the following are NOT lymphocytes?

A

M cells

51
Q

Which of the following is NOT a characteristic of B cells?

A

they recognize antigens associated with MHC

52
Q

Which of the following is the best definition of epitope?

A

specific regions on antigens that interact with antibodies

53
Q

The specificity of an antibody is due to:

A

the variable portions of the H and L chains

54
Q

IgM antibodies

A

first produced during initial infection

55
Q

IgA antibodies:

A

present in mother’s milk

56
Q

Which of the following makes IgG (IgM, IgE, IgA etc.) antibodies?

A

plasma B cell

57
Q

T/F Individual Plasma B cell produces many different antibody molecules.

A

False

58
Q

T/F Different clones of Plasma B cell produce identical antibody molecules.

A

False

59
Q

Which of the following bacterial components would most likely result in B cell stimulation by T-independent antigens?

A

bacterial capsule

60
Q

Which of the following is a possible outcome of antigen-antibody reaction?

A

opsonization, activation of complement, agglutination, and antigen neutralization

61
Q

When an antibody binds to a toxin, the resulting action is referred to as:

A

neutralization

62
Q

Reverse transcriptase of HIV virus lacks ‘proofreading activity’ (in other words makes many mistakes during reverse transcription of viral RNA to dsDNA). This can explain why HIV virus:

A

rapidly mutates and escapes the neutralization by produced antibodies

63
Q

In classical complement pathway, C1 protein binds to:

A

Fc (constant) region of antibodies bound to pathogen’s surface proteins

64
Q

T/F Activation of complement results in an interference with viral replication in infected cell.

A

False

65
Q

Which of the following is NOT a characteristic of cellular immunity?

A

naïve B cells make antibodies

66
Q

The adaptive immune system can be divided into two groups: ‘Humoral’ and ‘Cell mediated’. Which of the following are part of the ‘Cell mediated Immune system’?

A

CD8+ T cells

67
Q

These are secreted by T cells and function as a signaling molecules:

A

cytokines

68
Q

Clonal selection of T cells (i.e. activation and proliferation) takes place in:

A

lymph node

69
Q

T/F Antigen-binding receptors of T cells are identical to antigen-binding receptors of B cells.

A

False

70
Q

Antigen-presenting molecules are:

A

MHC proteins

71
Q

Which of the following cells are NOT an APC (antigen presenting) cells?

A

natural killer cells

72
Q

Cytokines released by TH cells:

A

activate CD8+ T cells to CTLs

73
Q

Which of the following destroys virus-infected cells?

A

CTLs

74
Q

A Treg (regulatory T cells) cell deficiency could result in:

A

autoimmunity

75
Q

What type of immunity results from vaccination?

A

artificially acquired active immunity

76
Q

What type of immunity results from transfer of antibodies from one individual to another individual by means of injection?

A

artificially acquired passive immunity

77
Q

What type of immunity results from recovery from mumps?

A

naturally acquired active immunity

78
Q

Newborns’ immunity due to the transfer of antibodies across the placenta is an example of:

A

naturally acquired passive immunity

79
Q

A DNA plasmid encoding a protein antigen from West Nile virus is injected into muscle cells of a horse. This is an example of a(n):

A

nucleic acid vaccine

80
Q

A patient shows the presence of antibodies against diphtheria toxin. Which of the following statements is FALSE?

A

The patient was near someone who had the disease

81
Q

Purified protein from Bordetella pertussis is used in a(n)

A

subunit vaccine

82
Q

Toxoid vaccines, such as the vaccines against Diphtheria and Tetanus, elicit a(n):

A

antibody response against these bacterial toxins

83
Q

Capsule polysaccharide plus diphtheria toxin is a(n):

A

conjugated vaccine

84
Q

Injection of purified antibodies is an example of what kind of vaccine?

A

toxoid vaccine

85
Q

An inanimate object that may be contaminated with a pathogen is called a:

A

fomite

86
Q

One example of infectious disease transmission by a fomite is:

A

a child developing a cold after playing with a toy that harbored rhinovirus

87
Q

T/F LD50 is the number of bacterial cells that will cause an infection in 50 percent of the test population.

A

False

88
Q

T/F ID50 is the number of bacterial cells that will result in death of 50 percent of the test population.

A

False

89
Q

Symptoms of intense inflammation and shock occur in some gram-positive bacterial infections due to:

A

super antigens

90
Q

T/F Superantigens are the endotoxins that attach to MHC and T cell receptor.

A

False

91
Q

Which of the following is TRUE?

A

endotoxins are part of the bacterial cell wall

92
Q

The toxic component of lipopolysaccharide is called:

A

lipid A

93
Q

T/F The “B” segment of the A-B toxin is responsible for its toxic enzymatic activity.

A

False

94
Q

Endotoxin is released when:

A

Gram-negative pathogens lyse or divide

95
Q

IgE antibodies

A

promote allergies

96
Q

igG antibodies

A

most abundant in blood

BIO SCI 101 (3 decks)

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