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Microbiology > Exam 3 (chapters 8, 9, 15, 20) > Flashcards

Exam 3 (chapters 8, 9, 15, 20) Flashcards

1
Q

Term for all genetic information in a cell:

A

genome

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2
Q

Term for segments of DNA that encode functional products, usually proteins:

A

genes

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3
Q

The ________ is a set of rules that determines how a nucleotide sequence is converted to an amino acid sequence of a protein.

A

genetic code

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4
Q

What are the four nitrogenous bases in DNA?

A

adenine, guanine, cytosine, thymine

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5
Q

What are the four nitrogenous bases in RNA?

A

adenine, cytosine, uracil, guanine

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6
Q

What two molecules make up chromosomes?

A

Each chromosome is made of protein and single molecule of DNA

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7
Q

How is the alteration of bacterial genes and gene expression important?

A

Helps understanding of cause of disease, how to prevent disease and treatment, can be manipulated for human benefit

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8
Q

List the chain of events described by central dogma:

A

DNA, mRNA, protein, function

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9
Q

Term for genetic makeup of an organism:

A

genotype

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10
Q

Term for expression of the genes (physical appearance of the organism in response to the genes expressed):

A

phenotype

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11
Q

Bacteria usually have what type of chromosome…made of ____ and _____?

A

single circular chromosome; single circular molecule of DNA; proteins

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12
Q

_____ are structures containing DNA that physically carry hereditary information.

A

chromosomes

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13
Q

What forms the basic structural unit of DNA?

A

nucleotides

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14
Q

What is a nucleotide made of?

A

nitrogenous base, pentose sugar, phosphate

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15
Q

What determines the genetic code?

A

the order of the nitrogen containing bases (contain the genetic instructions of the organism)

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16
Q

DNA forms a ______. The backbone consists of_____.

A

double helix; dexoxyribose-phosphate

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17
Q

Two strands of nucleotides are held together by ____ between A-_ and C-_.

A

hydrogen bonds; T; G

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18
Q

During DNA _____ one strand serves as a template for the production of a second strand.

A

replication

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19
Q

What has to happen to the DNA strands for replication to occur?

A

the strands have to separate

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20
Q

T/F DNA replication is more than 99% accurate

A

True

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21
Q

Why is replication highly accurate?

A

because of the proofreading capability of DNA polymerase (able to fix mistakes and proofreads as each nucleotide is added)

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22
Q

Most bacterial DNA replication is _______.

A

bidirectional (because it is a circular chromosome)

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23
Q

When does DNA replication occur in the life of a cell?

A

before cell division

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24
Q

How do bacteria divide?

A

binary fission

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25
Q

What two processes are involved in gene expression?

A

transcription and translation

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26
Q

When the information stored in our DNA is converted into instructions for making proteins or other molecules, it is called:

A

gene expression

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27
Q

Term for the synthesis of a complementary mRNA strand from a DNA template:

A

transcription (DNA > RNA)

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28
Q

Transcription begins when _____ binds to the ____ promoter sequence on DNA.

A

RNA polymerase; promoter

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29
Q

Transcription proceeds in the __’ to __’ direction.

A

5;3

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30
Q

T/F only one of the two DNA strands is transcribed during transcription

A

True

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31
Q

Transcription stops when it reaches the _____ sequence on DNA.

A

terminator

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32
Q

Term for the process where mRNA is translated into the “language” of proteins:

A

translation (RNA > PROTEIN)

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33
Q

What does transcription produce?

A

mRNA

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34
Q

Where does transcription take place in bacteria?

A

cytoplasm (because prokaryotes lack a membrane bound nucleus)

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35
Q

Where does transcription take place in eukaryotes?

A

membrane bound nucleus

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36
Q

What are groups of three mRNA nucleotides that code for a particular amino acid?

A

codons

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37
Q

How many codons encode the 20 amino acids:

A

64

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38
Q

Type of RNA that is an integral part of ribosomes:

A

ribosomal RNA (rRNA)

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39
Q

Type of RNA that transports amino acids during protein synthesis:

A

transfer RNA (tRNA)

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40
Q

Type of RNA that carries coded information needed to make protein from DNA to ribosomes:

A

messenger RNA (mRNA)

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41
Q

What are the three types of RNA?

A

ribosomal, transfer, messenger

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42
Q

Components of ribonucleic acid:

A

single-stranded nucleotide, 5-carbon ribose sugar, uracil instead of thymine

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43
Q

What does the process of translation produce?

A

proteins

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44
Q

Protein synthesis is called ______.

A

translation

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45
Q

Where does translation take place in bacteria?

A

cytoplasm

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46
Q

Where does translation occur in eukaryotes?

A

outside the nucleus in the cytoplasm

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47
Q

The genetic code involves ______, meaning each amino acid is coded by several codons.

A

degeneracy

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48
Q

How many amino acids does a cell need to make all of its proteins?

A

20

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49
Q

How many codons are there in the genetic code?

A

64

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50
Q

How are amino acids joined?

A

peptide bonds

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51
Q

Translation of mRNA begins at the:

A

start codon (AUG)

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52
Q

Translation ends at:

A

nonsense codons (UAA, UAG, UGA)

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53
Q

T/F In bacteria, transcription and translation can happen simultaneously…is this true in eukaryotic cells?

A

True. But they cannot occur simultaneously in eukaryotic cells because transcription occurs in the membrane bound nucleus and translation occurs in the cytoplasm

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54
Q

Term for self-replicating circular pieces of DNA:

A

plasmids

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55
Q

What often codes for proteins that enhance the pathogenicity of a bacterium?

A

plasmids

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56
Q

_____ and ______ are genetic elements that exist outside of chromosomes:

A

plasmids; transposons

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57
Q

Can plasmids be replicated?

A

Yes, they can replicate independently

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58
Q

Can plasmids be passed on to the next generation of bacterial cells?

A

Yes: increases pathogenicity

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59
Q

What are the three types of plasmids?

A

conjugative, dissimilation, resistance factors (R factors)

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60
Q

What carries genes for sex pili and transfer of the plasmid?

A

conjugative plasmid (horizontal gene transfer)

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61
Q

What encodes enzymes for the catabolism of unusual compounds?

A

dissimilation plasmids

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62
Q

What encodes antibiotic resistance?

A

resistance factors (R factors)

63
Q

How do bacteria reproduce?

A

binary fission

64
Q

Three ways that bacteria create genetic variation:

A

transformation, conjugation, transduction

65
Q

When genes are transferred from one bacterium to another as “naked” DNA:

A

transformation

66
Q

What are the two ways transformation can occur?

A

Naturally and artificially (in lab)

67
Q

How is natural transformation beneficial or not to bacteria?

A

less prevalent (few bacteria take up the DNA–only those that are competent). PROS: plasmids can be acquired this way, and increased antibiotic resistance.

68
Q

How is artificial transformation in bacteria useful?

A

recombinant DNA technology

69
Q

When plasmids are transferred from one bacterium to another–requires cell-to-cell contact via sex pili:

A

conjugation

70
Q

Term for the donor cells that carry the plasmid:

A

F plasmid

71
Q

Cells that contain the F factor on the chromosome:

A

Hfr cells

72
Q

Transduction can transfer bacterial DNA from one cell to another via:

A

bacteriophage

73
Q

Term for the use of microorganisms, cells, or cell components to make a product such as: food, antibiotics, enzymes, vitamins:

A

biotechnology

74
Q

Term for the insertion or modification of genes to produce desired proteins:

A

recombinant DNA

75
Q

What cuts specific sequences of DNA as a way to destroy bacteriophage DNA in bacterial cells?

A

restriction endonucleases

76
Q

What carries new DNA to desired cells and must be able to self-replicate?

A

vectors

77
Q

What can be used as vectors?

A

plasmids and viruses

78
Q

What enzyme is used to splice a gene of interest into a vector?

A

DNA ligase

79
Q

When the recombinant DNA plasmid can be introduced into a host organism, this is called:

A

transformation

80
Q

Process of increasing small quantities (amplifying) of DNA for analysis:

A

Polymerase Chain Reaction (PCR)

81
Q

Why would someone use PCR in the lab?

A

diagnostic tests for genetic disease and to detect pathogens

82
Q

What are the requirements for PCR?

A

DNA template, primers, Taq polymerase, nucleotides, thermocycler

83
Q

Term for the sample used for PCR testing:

A

DNA template

84
Q

Short pieces of nucleic acid that help start the reaction during PCR testing:

A

primers

85
Q

What is the enzyme used to synthesize the new copy of DNA (comes from a hot spring prokaryote called Thermus aquaticus):

A

Taq polymerase

86
Q

More examples of PCR uses:

A

DNA fingerprinting, gene cloning, forensic science, medical diagnosis, microbial detection

87
Q

Name some therapeutic application for recombinant DNA technology:

A

insulin production using human enzymes, subunit vaccines, gene therapy, gene slicing,

88
Q

Term for understanding gene function via computer-assisted analysis:

A

bioinformatics

89
Q

Term for the ability to cause disease:

A

pathogenicity

90
Q

Term for the degree of pathogenicity

A

virulence

91
Q

What is the preferred portal of entry?

A

GI and respiratory

92
Q

This measures the virulence of a microbe based on infectious dose needed to cause illness in 50% of population:

A

ID50

93
Q

This measures the potency of a toxin what is needed as a lethal dose to cause lethality in 50% of a sample population:

A

LD50

94
Q

Almost all pathogens attach to host tissues in a process called ______.

A

adherence

95
Q

The attachment between pathogen and host is accomplished by means of surface molecules on the pathogen called ____ or _____ that bind specifically to complementary surface receptors on the cells of certain host tissues.

A

adhesins; ligands

96
Q

Where can adhesins be located?

A

glycocalyx, pili, fimbriae, flagella

97
Q

What are the ways a microbe can penetrate host defenses?

A

capsules, cell wall components, enzymes, antigenic variation, penetration into host, biofilms

98
Q

How can microbes evade the immune system?

A

impairment of phagocytosis

99
Q

What is a heat-resistant, acid-resistant, component found on the cell surface and fimbriae? It helps bacterium resist phagocytosis and mediates attachment of bacterium to epithelial cells of the host.

A

M protein

100
Q

What is a protein that allows attachment to host cells and facilitates the host cell’s intake of the bacterium (also resists phagocytosis)?

A

Opa

101
Q

What resists digestion by phagocytosis?

A

mycolic acid

102
Q

Name the exoenzymes (5):

A

coagulases, kinases, hyaluronidase, collagenase, IgA proteases

103
Q

This is an exozyme that coagulates fibrinogen to form clots in the host that can protect the bacterium from phagocytosis:

A

coagulases

104
Q

Example of a coagulase:

A

Staphylococci

105
Q

This is an exozyme that digests fibrin clots the host uses to isolate the infection:

A

kinases

106
Q

Example of kinase:

A

Streptococcus pyogenes

107
Q

This is an exozyme that digests polysaccharides that hold cell together to help pathogen spread from the initial infection site (promotes circulation of the pathogen):

A

hylauronidase

108
Q

Example of hyaluronidase:

A

streptococci, clostridia

109
Q

This exozyme breaks down collagen to facilitate the spread of gas gangrene:

A

collagenase

110
Q

This exozyme destroys IgA antibodies secreted by mucous membranes:

A

IgA proteases

111
Q

Term for a pathogen’s ability to alter their surface antigens so that antibodies are rendered ineffective which allows them to evade the adaptive immune system:

A

antigenic variation

112
Q

Proteins secreted by pathogens that bind iron more tightly than host cells thus robbing the host cell of major nutrients:

A

siderophores

113
Q

Term for poisonous substances produced microorganisms (produce fever, cardiovascular problems, diarrhea, shock):

A

toxins

114
Q

The ability of a microorganism to produce a toxin:

A

toxigenicity

115
Q

The presence of toxin in the host’s blood:

A

toxemia

116
Q

The presence of toxin without microbial growth:

A

intoxications (only a small amount of the organism is needed to make you sick)

117
Q

What are two types of toxins?

A

exotoxins and endotoxins

118
Q

(Endotoxin or Exotoxin) This type is very specific in its effect and causes disease-specific signs and symptoms; soluble in body fluids; proteins are secreted and produced by the bacteria.

A

Exotoxins

119
Q

List examples of exotoxins:

A

A-B toxins, membrane-disrupting toxins, superantigens, genotoxins

120
Q

Most exotoxins fall in this category. Contain an enzyme component (A–alters function of host cell) and a binding component (B–helps make contact with host cell):

A

A-B toxins

121
Q

What type of exotoxin (broad category) lyse host cells by disrupting plasma membranes:

A

membrane-disrupting toxins

122
Q

Examples of membrane-disrupting toxins:

A

leukocidins, hemolysins, streptolysins

123
Q

What type of toxin (endo- or exotoxin) is part of the outer portion of the cell wall of gram-negative bacteria?

A

endotoxins

124
Q

Endotoxin that is part of gram negative bacteria:

A

Lipid A

125
Q

Do you all endotoxins cause the same signs and symptoms regardless of the species of microbe? What are those symptoms?

A

Yes; chills, fever, weakness, aches

126
Q

What kinds of symptoms are unique to endotoxins?

A

activation of blood clotting

127
Q

Term for visible effects of viral infection on a cell (changes the way the cell behaves):

A

cytopathic effects (CPE)

128
Q

Name some cytopathic effects:

A

causing cell lysosomes to release enzymes, changing host cell function or inducing chromosomal changes, inducing antigenic changes on cell surface

129
Q

What can cause disease but does not have a well-defined set of virulence factors (more nondescript)?

A

fungi

130
Q

What type of microbe provokes an allergic response?

A

fungi

131
Q

This type of microbe causes symptoms due to their waste products:

A

protozoa

132
Q

How do protozoa avoid host defenses?

A

digesting cells and tissue fluids, growing in phagocytes, antigenic variation

133
Q

How do helminths cause problems for a host?

A

use host tissue for growth, produce waste products, cause cellular damage such as lymphedema (roundworm)

134
Q

What type of microbe produces a neurotoxin called saxitoxin?

A

algae

135
Q

Selectively finding and destroying pathogens without damaging the host:

A

selective toxicity

136
Q

Use of chemical to treat disease:

A

chemotherapy (any med. to help overcome disease)

137
Q

A substance produced by a microbe that in small amounts INHIBITS another microbe:

A

antibiotic

138
Q

Synthetic substances that interfere with the growth of microbes:

A

antimicrobial drugs

139
Q

When did Fleming discover penicillin and when was it first used on humans?

A

1928 (discovered); 1940 (first clinical trials)

140
Q

More than half of our antibiotics are produced by _____ species of bacteria that commonly inhabit soil.

A

Streptomyces

141
Q

Drugs that affect a narrow range of microbial types:

A

narrow spectrum drug

142
Q

Drug that affect a broad range of gram-positive or gram-negative bacteria–also can destroy the normal microbiota of the host–can also cause the normal microbiota to flourish and become opportunistic pathogens:

A

broad-spectrum antibiotics

143
Q

Term for an overgrowth of normal microbiota that is resistant to antibiotics:

A

surperinfection

144
Q

Are eukaryotic or prokaryotic pathogens harder to treat?

A

eukaryotic (due to their similarity to host cells

145
Q

Name of test that tests the effectiveness of chemotherapeutic agents:

A

Kirby-Bauer (disk diffusion) test

146
Q

MIC stands for:

A

Minimal inhibitory concentration

147
Q

Test that determines lowest antibiotic concentration preventing bacterial growth:

A

E test (determines minimal inhibitory concentration)

148
Q

These cells have genetic characteristics allowing for their survival when exposed to an antibiotic:

A

Persister cells

149
Q

Bacteria that are resistant to large numbers of antibiotics:

A

Superbugs

150
Q

Five mechanisms of resistance:

A
  1. Enzymatic destruction or inactivation of drug 2. Prevention of penetration to the target site 3. Alteration of drug’s target site 4. Rapid efflux of antibiotic 5. Variation of these/combination of mechanisms
151
Q

When the effect of two drugs together is greater than using one, it is called:

A

Synergism

152
Q

When the effect of two drugs is less than the effect of either one, it is called:

A

Antagonism

153
Q

Five actions of anti microbial drugs:

A
  1. Inhibiting cell wall synthesis 2. Inhibiting protein synthesis 3. Injuring plasma membrane 4. Inhibiting nucleic acid synthesis 5. Inhibiting the synthesis of essential metabolites

Microbiology (7 decks)

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