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Introduction to Microbiology Flashcards

1
Q

What is microbiology?

A

The science dealing with tiny creatures usually invisible to the naked eye, known as microbes.

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2
Q

What are the two main classifications of living organisms?

A

Prokaryotes and eukaryotes.

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3
Q

What are prokaryotes?

A

Primitive cells without organelles.

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4
Q

What are eukaryotes?

A

More complex cells with organelles.

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5
Q

Describe the structure of bacteria.

A

Single cells with a cell membrane, cell wall, and sometimes a capsule, containing a circular chromosome and possibly plasmids.

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6
Q

How do bacteria reproduce?

A

By binary fission.

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7
Q

What is gram staining?

A

A method to distinguish bacteria based on their cell wall properties, classifying them as gram-positive or gram-negative.

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8
Q

What is the energy production outcome of aerobic respiration in bacteria?

A

Produces 38 ATP molecules.

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9
Q

What is the energy production outcome of anaerobic respiration in bacteria?

A

Produces less ATP than aerobic respiration.

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10
Q

What is the primary difference in energy production between fermentation and respiration in bacteria?

A

Fermentation produces only 2 ATP molecules.

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11
Q

What are the main components of the viral structure?

A

Viral capsid and, in some cases, an outer envelope.

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12
Q

What is the function of viral attachment proteins?

A

They bind to specific host cell receptors, determining the virus’s host specificity.

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13
Q

What types of genomes can viruses have?

A

Either DNA or RNA, but not both.

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14
Q

What is the role of the capsid in a virus?

A

Protects the viral genome and aids in host cell attachment.

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15
Q

What distinguishes enveloped viruses from naked viruses?

A

Enveloped viruses have a lipid bilayer derived from the host cell membrane.

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16
Q

Define opportunistic mycoses.

A

Infections caused by fungi that are normally harmless but can cause disease in immunocompromised individuals.

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17
Q

What are the two main types of parasites?

A

Protozoa and helminths.

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18
Q

What is the significance of fungal morphology in microbiology?

A

It is crucial for identifying and treating fungal infections.

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19
Q

What is the classification of mycoses based on?

A

The tissues they infect and the characteristics of the fungi.

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20
Q

What is the difference between exogenous and endogenous infections?

A

Exogenous infections are caused by pathogens from external sources; endogenous infections occur from the host’s own microbiota.

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21
Q

What are the key factors that increase susceptibility to infections?

A
  • Age
  • Pre-existing conditions
  • Immune suppression
  • Malnutrition
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22
Q

What are bacterial toxins?

A

Can be exotoxins or endotoxins, causing tissue damage and inflammation.

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23
Q

What is the primary role of microbiota in human health?

A

Preventing invasion of harmful species and maintaining ecological niches.

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24
Q

Fill in the blank: Fungi have a cell wall made of _______.

A

[chitin, glucan, and mannan]

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25
True or False: HIV is a retrovirus that integrates its RNA into the host cell's DNA.
True
26
What are the two forms that dimorphic fungi can take?
* Mold * Yeast
27
What is the process of infection?
Involves attachment, immune evasion, and exit of the pathogen.
28
What are the types of symbiotic relationships?
* Commensalism * Mutualism * Parasitism
29
What type of bacteria are found in the gastrointestinal tract of breastfed infants?
Lactic acid streptococci and lactobacilli ## Footnote These bacteria are introduced through breastfeeding.
30
What is the effect of bottle-feeding on infant gut microbiota?
Greater variety of organisms ## Footnote Bottle-feeding results in a more diverse microbiota composition.
31
Why are newborns given vitamin K at birth?
To prevent hemorrhagic disease ## Footnote Newborns lack established gut flora to produce vitamin K.
32
What relationship type describes one species benefiting without harming the other?
Commensalism
33
What is mutualism in symbiotic relationships?
Both species benefit, and the relationship may be obligatory for one or both
34
Define parasitism in the context of symbiotic associations
One species benefits at the expense of the other
35
What do intestinal bacteria primarily do?
Ferment digested food and acquire nutrients
36
What can happen to intestinal bacteria if the host's immunity is compromised?
They can become pathogenic
37
What role do Bacteroid species play in the cattle rumen?
Metabolize host food to fatty acids used as an energy source
38
What factors increase susceptibility to infections?
* Age * Pre-existing conditions * Immune suppression * Malnutrition
39
How does age affect susceptibility to infections?
Young and elderly have increased susceptibility due to immature or weakened immune systems
40
What is the relationship between organ transplants and infection risk?
Transplants require immune suppressive therapy, increasing infection risk
41
What role do prosthetic devices have in infection risk?
They can create a medium for microorganism growth, increasing infection risk
42
What defines pathogenic infections?
Caused by microbes that always result in disease
43
Give an example of a viral pathogenic infection
Rabies caused by the rabies virus
44
What is a characteristic of opportunistic infections?
They occur when the host's immune defenses are compromised
45
What can Staphylococcus aureus cause if it enters deeper tissues?
Infections
46
What are exogenous pathogens?
Pathogens that come from outside the host and cause infections
47
What is an example of an exogenous infection?
Influenza virus causing respiratory infections
48
What defines endogenous infections?
Caused by pathogens originating from the host's own microbiota
49
How can E. coli cause bladder infections?
By moving from the gastrointestinal tract to the bladder
50
What are the three steps involved in the process of infection?
* Attachment and entry * Immune evasion * Exit
51
What are exotoxins?
Proteins produced by bacteria causing specific effects
52
What are endotoxins?
Lipid components of gram-negative bacteria that trigger immune responses
53
What does tetanus toxin do?
Causes spastic paralysis by interfering with motor neuron signaling
54
What can viral infections lead to?
* Acute infections with rapid replication * Chronic infections with genome integration
55
What is a characteristic of fungal infections?
They can range from superficial to systemic
56
What can cause opportunistic fungal infections?
Overgrowth of fungi that are normally harmless due to immune suppression
57
What techniques do microbiology labs use to identify microorganisms?
* Culture techniques * Microscopy * Biochemical tests
58
What is the microbiota?
Microorganisms living on our skin, body, mucous membranes, and tissues
59
How does microbiota contribute to health?
* Preventing invasion of harmful species * Producing antimicrobial factors * Maintaining ecological niches
60
What are endotoxins?
Lipid components of gram-negative bacteria that trigger immune responses. ## Footnote Endotoxins are released upon the death of the bacterial cell.
61
How do exotoxins differ from endotoxins?
Exotoxins are secreted by bacteria, while endotoxins are part of the bacterial cell wall. ## Footnote Exotoxins are released actively, whereas endotoxins are released when the bacteria die.
62
What is tetanus toxin?
An exotoxin produced by Clostridium tetani that causes spastic paralysis. ## Footnote Tetanus toxin interferes with motor neuron signaling.
63
What are the characteristics of viral infections?
Viruses can cause acute infections with rapid replication or chronic infections with genome integration. ## Footnote Chronic infections may lead to cancer, such as liver cancer from hepatitis B virus.
64
What is the role of hepatitis B virus in cancer development?
It can integrate into the host genome, leading to liver cancer. ## Footnote The integration of viral DNA can activate oncogenes.
65
What are the types of fungal infections?
Fungal infections range from superficial to systemic. ## Footnote Superficial infections affect skin and nails, while systemic infections can spread throughout the body.
66
What causes opportunistic fungal infections?
Occur when normal flora overgrow, such as Candida albicans causing thrush. ## Footnote This often happens in immunocompromised individuals.
67
What symptoms can Candida albicans cause?
Symptoms include white patches in the mouth or vaginal discharge. ## Footnote These symptoms occur when Candida overgrows in the mouth or vagina.
68
What techniques are used in microbiology labs?
Culture techniques, microscopy, and biochemical tests to grow and identify microorganisms. ## Footnote These techniques help in diagnosing infections by isolating and identifying pathogens.
69
What is the purpose of culturing in microbiology?
To grow and identify microorganisms. ## Footnote Specific media are used for culturing various types of microbes.
70
What is the significance of microscopy in microbiology?
Helps in visualizing microorganisms for identification. ## Footnote Microscopy is crucial for diagnosing infections.
71
Fill in the blank: Fungal infections can be classified based on their _______.
depth of penetration into the host tissues.
72
73
What is the difference between bacteriocidal and bacteriostatic antibiotics?
Bacteriocidal antibiotics kill bacteria, while bacteriostatic antibiotics inhibit bacterial growth by stopping cell division.
74
What is the primary difference between narrow-spectrum and broad-spectrum antibiotics?
Narrow-spectrum antibiotics are effective mainly against either gram positive or gram negative bacteria, while broad-spectrum antibiotics act against both.
75
Are the terms antimicrobial and antibiotics interchangeable?
Yes, the terms antimicrobial and antibiotics are used interchangeably.
76
What is a characteristic of gram positive bacteria's cell wall?
Gram positive bacteria have a thick peptidoglycan cell wall.
77
What distinguishes gram negative bacteria's cell wall structure?
Gram negative bacteria have a thinner peptidoglycan layer and an outer membrane.
78
Why is it important to understand the differences in bacterial cell wall structures?
It influences antibiotic selection for effective treatment.
79
List the main targets of antibiotics in bacterial cells.
* Cell wall synthesis * Protein synthesis * Nucleic acid synthesis * Folate synthesis
80
What mechanism do aminoglycosides like streptomycin use to exert their effect?
They interfere with bacterial protein synthesis by binding to the bacterial ribosome.
81
What are beta-lactams and provide examples?
Beta-lactams include penicillin and cephalosporins, with examples like ampicillin and amoxicillin.
82
What is the role of beta-lactamase inhibitors?
They prevent degradation of the beta-lactam ring, allowing beta-lactam antibiotics to remain effective.
83
What do sulfonamides and trimethoprim inhibit?
They inhibit folate synthesis.
84
What type of infections can MRSA cause?
MRSA infections can present as cutaneous abscesses.
85
How does beta-lactamase contribute to bacterial resistance?
It breaks down the beta-lactam ring in antibiotics, rendering them ineffective.
86
What was methicillin designed to do?
Methicillin was designed to overcome beta-lactamase activity but led to the emergence of MRSA.
87
True or False: MRSA infections can only occur in hospital settings.
False. MRSA infections can occur in both hospital settings and the community.
88
Fill in the blank: A broad-spectrum antibiotic is effective against both _______ and _______ bacteria.
gram positive; gram negative
89
What is a common strategy to overcome beta-lactamase activity?
Modification in the antibiotic structure, such as adding bulky R groups.

General Principles (7 decks)

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