Introduction to Medical Microbiology Flashcards
1
Q
What is a key structural difference between prokaryotic and eukaryotic cells regarding the nucleus?
A
Prokaryotes lack a membrane-bound nucleus, while eukaryotes have a distinct nucleus enclosed by a nuclear membrane.
2
Q
What type of organelles do prokaryotic cells possess?
A
Prokaryotes have no membrane-bound organelles.
3
Q
List three examples of membrane-bound organelles found in eukaryotic cells.
A
- Mitochondria
- Endoplasmic reticulum
- Golgi apparatus
4
Q
How is the DNA structured in prokaryotic cells?
A
Prokaryotic DNA is typically circular and located in the nucleoid region of the cytoplasm.
5
Q
In which part of the cell is eukaryotic DNA contained?
A
Eukaryotic DNA is linear and contained within the nucleus.
6
Q
What is the typical size range of prokaryotic cells?
A
Prokaryotic cells are generally smaller, ranging from 0.1 to 5.0 μm in diameter.
7
Q
What is the typical size range of eukaryotic cells?
A
Eukaryotic cells are typically 10-100 μm in diameter.
8
Q
What type of ribosomes do prokaryotic cells have?
A
Prokaryotes have smaller 70S ribosomes.
9
Q
What type of ribosomes do eukaryotic cells have?
A
Eukaryotes have larger 80S ribosomes.
10
Q
What is the primary function of the cell wall in bacterial cells?
A
Provides structural support and protection
Composed of peptidoglycan
11
Q
What is the role of the plasma membrane in bacterial cells?
A
Controls what enters and exits the cell
12
Q
What is contained within the cytoplasm of bacterial cells?
A
Supports and protects cell organelles and contains nutrients
13
Q
Where is the bacterial chromosome located?
A
In the nucleoid region
14
Q
What is a plasmid?
A
Extra chromosomal DNA that can confer antibiotic resistance
15
Q
What is the function of ribosomes in bacterial cells?
A
Responsible for protein synthesis
16
Q
What do inclusion/storage granules store?
A
Nutrients like sugars and fats
17
Q
What is the function of flagella in bacteria?
A
Aid in bacterial locomotion
18
Q
What role do pili play for bacteria?
A
Help bacteria attach to surfaces and other cells
19
Q
What is the main structural difference between gram-positive and gram-negative bacteria?
A
Gram-positive have a thick peptidoglycan layer; gram-negative have a thin layer with an outer membrane
20
Q
What color do gram-positive bacteria appear after staining?
A
Purple
21
Q
What color do gram-negative bacteria appear after staining?
A
Red
22
Q
Why are gram-negative bacteria generally more resistant to antibiotics?
A
Due to their impenetrable cell wall
23
Q
What type of toxins do gram-positive bacteria typically produce?
A
Exotoxins
24
Q
What type of toxins do gram-negative bacteria typically produce?
A
Endotoxins
25
What process do bacteria use to grow and divide?
Binary fission
26
What is the first step in the binary fission process?
DNA Replication
27
What happens during chromosome segregation in binary fission?
The replicated chromosomes are separated
28
What is formed between the two chromosomes during binary fission?
A septum
29
What is the term for the time taken for a bacterial population to double?
Generation time
30
What is the typical generation time for many medically significant bacteria?
Around 20 minutes
31
What are the components that make up a virus?
Viruses consist of:
* Genetic Material: Either DNA or RNA
* Capsid: A protein coat that protects the genetic material
* Envelope: A lipid membrane surrounding the capsid (in some viruses)
## Footnote
The envelope is not present in all viruses.
32
What are the shapes that viruses can have?
Viruses can have various shapes, including:
* Icosahedral
* Helical
* Complex structures
## Footnote
The shape of a virus can affect its method of infection and replication.
33
What is the size range of viruses?
Extremely small, ranging from 20 to 300 nanometers
## Footnote
This small size allows viruses to easily infect host cells.
34
True or False: Viruses are considered cellular organisms.
False
## Footnote
Viruses are acellular and lack cellular organelles.
35
What type of parasites are viruses classified as?
Obligate Intracellular Parasites
## Footnote
They can only replicate inside host cells.
36
What does 'specific host range' mean in the context of viruses?
Each virus can infect only specific types of cells or organisms
## Footnote
This specificity is determined by the interaction between viral surface proteins and host cell receptors.
37
What are the seven stages of the viral replication cycle?
1. Attachment
2. Entry
3. Uncoating
4. Replication
5. Assembly
6. Maturation
7. Release
## Footnote
Each stage is crucial for the successful replication of the virus.
38
What happens during the 'uncoating' stage of viral replication?
The viral genetic material is released inside the host cell
## Footnote
This step is essential for the virus to begin using the host's cellular machinery.
39
Fill in the blank: Viruses can undergo either a _______ cycle or a _______ cycle.
lytic, lysogenic
## Footnote
The lytic cycle results in the destruction of the host cell, while the lysogenic cycle integrates the viral genome into the host genome.
40
What occurs during the 'maturation' stage of the viral replication cycle?
The newly formed viruses undergo final changes to become infectious
## Footnote
Maturation is critical for the viruses to be able to infect other cells.
41
What is the primary component that encloses the genetic material in eukaryotic microbes?
Nucleus
## Footnote
The nucleus is a defining feature of eukaryotic cells, distinguishing them from prokaryotic cells.
42
Name three membrane-bound organelles found in eukaryotic microbes.
* Mitochondria
* Endoplasmic reticulum
* Golgi apparatus
## Footnote
These organelles perform various essential functions, including energy production and protein processing.
43
What is the composition of the cell wall in fungi?
Chitin
## Footnote
Chitin is a strong, flexible compound that provides structural support to fungal cells.
44
What structure in eukaryotic microbes provides support and enables movement?
Cytoskeleton
## Footnote
The cytoskeleton is crucial for maintaining cell shape and facilitating intracellular transport.
45
How do fungi primarily reproduce?
Sexually or asexually, often through spore formation
## Footnote
Spores are a common reproductive structure that allows fungi to spread and colonize new environments.
46
What is a characteristic of the life cycles of parasites?
Involves multiple hosts and stages
## Footnote
This complexity can complicate treatment and control efforts.
47
List three mechanisms by which eukaryotic microbes can cause disease.
* Tissue invasion
* Toxin production
* Immune evasion
## Footnote
Each of these mechanisms can significantly impact the host's health.
48
What challenge arises from the similarity of eukaryotic pathogens to host cells?
Difficulty in targeting pathogens without harming host cells
## Footnote
This similarity complicates the development of specific treatments.
49
Why are complex life cycles a challenge in treating eukaryotic pathogens?
They make pathogens hard to eliminate completely
## Footnote
Understanding these life cycles is essential for effective treatment strategies.
50
What issue can arise with some fungi and parasites regarding treatments?
Drug resistance
## Footnote
The ability to develop resistance can lead to treatment failures and necessitate ongoing research for new therapies.
51
What is the first step in the process of infection?
Entry
## Footnote
Pathogens enter the host through various routes.
52
How do bacterial pathogens typically enter the host?
Through breaks in skin, mucous membranes, or ingestion.
53
What is a common entry route for viral pathogens?
Often through respiratory or mucosal routes.
54
How do fungal pathogens commonly enter the host?
Often through inhalation of spores or skin contact.
55
What is the entry method for helminthic and parasitic pathogens?
Usually through ingestion or skin penetration.
56
What is the second step in the infection process?
Adherence
## Footnote
Pathogens attach to host cells.
57
How do bacterial pathogens adhere to host cells?
Using pili or adhesins.
58
What mechanism do viral pathogens use for adherence?
Via specific receptor binding.
59
How do fungal pathogens attach to host cells?
Through adhesins.
60
What structures do helminthic and parasitic pathogens use to adhere?
Using hooks, suckers, or other specialized structures.
61
What is the third step in the infection process?
Invasion
## Footnote
Pathogens penetrate host tissues.
62
How do bacterial pathogens invade host tissues?
Some remain extracellular, others enter cells.
63
What is the method of invasion for viral pathogens?
Enter host cells for replication.
64
How do fungal pathogens invade tissues?
Can invade tissues or remain superficial.
65
How do helminthic and parasitic pathogens usually invade?
Often migrate through tissues to specific organs.
66
What is the fourth step in the infection process?
Multiplication
## Footnote
Pathogens increase in number.
67
How do bacterial pathogens multiply?
Divide by binary fission.
68
What is the replication method for viral pathogens?
Replicate using host cell machinery.
69
How do fungal pathogens grow?
By extending hyphae or budding.
70
What is a characteristic of helminthic and parasitic multiplication?
Often involve complex life cycles with multiple stages.
71
What is the fifth step in the infection process?
Spread
## Footnote
Pathogens can spread locally or systemically.
72
How can pathogens spread within the host?
Through blood or lymph.
73
What is the sixth step in the infection process?
Tissue Damage
## Footnote
Caused by direct pathogen activity or host immune response.
74
What types of tissue damage can occur during an infection?
* Direct damage from pathogen activity
* Indirect damage from host immune response
75
What is the final step in the infection process?
Shedding
## Footnote
Release of pathogens from the host.
76
What occurs during the shedding step of infection?
Release of pathogens from the host to potentially infect others.
77
What are normal flora?
Microorganisms that naturally inhabit various body regions
78
What roles do normal flora play in health?
They help prevent colonization by harmful microbes and aid in digestion and immune function
79
What type of microorganisms primarily inhabit the skin?
Bacteria
80
What is the role of bacteria in the gastrointestinal tract?
Aid in digestion and immune function
81
What type of bacteria are found in the respiratory tract?
Bacteria that help prevent colonization by pathogens
82
What is the function of bacteria in the urogenital tract?
Maintain pH and prevent infections
83
Define mutualism in symbiotic relationships
Both organisms benefit
84
Provide an example of mutualism
Gut bacteria aiding in digestion
85
Define commensalism in symbiotic relationships
One organism benefits while the other is unaffected
86
Provide an example of commensalism
Some skin bacteria
87
Define parasitism in symbiotic relationships
One organism benefits at the expense of the other
88
Provide an example of parasitism
Intestinal worms
89
What are narrow spectrum antibiotics?
Target specific types of bacteria
## Footnote
Examples include Penicillin G (effective against gram-positive bacteria) and Vancomycin (targets gram-positive bacteria)
90
What are the advantages of narrow spectrum antibiotics?
Less likely to cause antibiotic resistance, fewer side effects
91
What are the disadvantages of narrow spectrum antibiotics?
Require accurate diagnosis before prescription
92
What are broad spectrum antibiotics?
Effective against a wide range of bacterial types
## Footnote
Examples include Tetracyclines and Chloramphenicol
93
What are the advantages of broad spectrum antibiotics?
Can be used empirically before specific pathogen identification
94
What are the disadvantages of broad spectrum antibiotics?
Higher risk of antibiotic resistance, more likely to disrupt normal flora
95
What is the mode of action of beta-lactams?
Inhibit cell wall synthesis
96
What do beta-lactams target?
Peptidoglycan layer of bacterial cell wall
97
What is the mode of action of aminoglycosides?
Inhibit protein synthesis
98
What do aminoglycosides target?
30S ribosomal subunit
99
What is the mode of action of tetracyclines?
Inhibit protein synthesis
100
What do tetracyclines target?
30S ribosomal subunit
101
What is the mode of action of macrolides?
Inhibit protein synthesis
102
What do macrolides target?
50S ribosomal subunit
103
What is the mode of action of fluoroquinolones?
Inhibit DNA replication
104
What do fluoroquinolones target?
DNA gyrase and topoisomerase IV
105
What is the mode of action of sulfonamides?
Inhibit folic acid synthesis
106
What do sulfonamides target?
Enzyme involved in folic acid production
107
What is the mode of action of glycopeptides?
Inhibit cell wall synthesis
108
What do glycopeptides target?
Peptidoglycan precursors
109
What is the significance of bacteria producing beta-lactamase?
Antibiotic resistance
110
How do beta-lactamase enzymes affect antibiotics?
They can hydrolyze the beta-lactam ring, rendering antibiotics ineffective
111
What is a consequence of infections caused by beta-lactamase-producing bacteria?
May not respond to first-line antibiotic treatments, leading to prolonged illness
112
What is a potential issue with the spread of beta-lactamase genes?
Can be transferred between bacteria, leading to widespread antibiotic resistance
113
What has the prevalence of beta-lactamase-producing bacteria driven?
The development of new antibiotics and beta-lactamase inhibitors
114
What must healthcare providers consider when selecting antibiotics?
The possibility of beta-lactamase production
115
What challenge does the spread of beta-lactamase-producing bacteria pose?
Significant challenge to infection control and patient safety
