Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Medical Sciences > MICROBIOME AND PATHOGENESIS > Flashcards

MICROBIOME AND PATHOGENESIS Flashcards

(66 cards)

Start Studying
1
Q

Microbiota

A

An individuals microbes, vary between site and individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Normal flora

A

Microbiota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Microbiome

A

Microbes and aggregate of microbial genomes in the microbiota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Core microbiome

A

Commonly shared species at a specific site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Secondary microbiome

A

Species that contribute to diversity in an individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe gut microbiota

A

Highest number of organisms in bodily niche

Seeded at birth - affected by child delivery option

Rapidly diversified

Typical adult profile within first few years of life

Common phyla include Firmicutes and Bacteroidetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are roles of the microbiome?

A

Digestion, producing vitamins and minerals

Protect against pathogens

Regulate immune system

Possibly contribute to mood and behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Structure of a virus

A

Lack cytoplasm

Proteins synthesised on host ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe prokaryotes structure

A

Lack cytoskeleton

Shape determined by cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe eukaryotes structure

A

Cytoskeleton
Complex internal structure
Arches like information processing
Bacteria like metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe archaea structure

A

Ether linked membrane lipids

Unique metabolic features

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe bacteria structure

A

Eater linked membrane lipids

Peptidoglycan cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the cell wall

A

Main load bearing structure

Resists osmotic pressure and determines cell shape

Peptidoglycan (Murien) - polysaccharide chains with peptide cross links

Signal to innate immune system of bacterial presence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the gram positive bacteria cell wall

A

Thick cell wall made up of many layers of murein.

Several constituents (teichoic acids, lipoteichoic acids and protein) protrude from this layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the structure of the gram negative bacterial cell wall

A

Thin cell wall and outer membrane

Outer leaflet of the outer membrane is made up of lipopolysaccharide

Space between the 2 membranes is the periplasm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe peptidoglycan structure

A

Alternating N-acetylglucosamine and N-acetyl-muramic acid

Peptide cross links attached to NAM residues

It is thick (20-25 layers) in gram positive bacteria

It is thin (1-3 layers) in gram negative bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the peptidoglycan arrangement in gram positive bacteria?

A

It was previously assumed that it would be in multiple layers but now evidence exists that it is wound into cables which are wrapped around the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describes the peptidoglycan arrangement in gram negative rods

A

Polysaccharide chains wrapped around the circumference of cell, peptide cross links parallel to cell axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the cell membrane

A

It is a phospholipid bilayer

It is the main permeability barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe capsules

A

Amorphous polysaccharide slime surrounding cell

Presence and composition strain - specific

Environment - prevents desiccation

In animal hosts : inhibits phagocytosis

Attachment to surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the structure and function of flagella

A

Generate thrust by rotation at 200-1000 rpm

Attached via hook and basal body containing motor proteins (driven by proton gradient) and switch proteins (control direction of rotation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe pili and fimbriae

A

Protein spikes used to attach to surfaces

Type 1 fimbriae required for pathogenic Escherichia Coli strains to adhere to urethra to cause UTI

Sex Loki involved in DNA transfer in conjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the 4 basic viral forms

A

Icosahedral nucleocapsid

Enveloped icosahedron

Helical, non enveloped

Helical, enveloped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the structures in a icosahedral nucleocapsid virus

A

Capsomeres (proteins)

Nucleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the structures in an enveloped icosahedron virus
Nucleic acid Envelope consists of phospholipid and glycoproteins
26
Describe the structures of the helical non enveloped virus
Nucleic acid Proteins
27
Describe the structures in the helical enveloped virus
Nucleic acid Envelope: phospholipid and glycoprotein
28
How are virus’ classified?
By the presence/absence of the envelope By The type of nucleic acid present is the Baltimore classification
29
What are the viral forms?
RNA viruses DNA viruses
30
Describe the viral lifecycle
Attachment and entry to host Uncoating Replication Assembly and maturation Released by budding
31
What is commensalism?
One of the 2 organisms in a relationship benefits. The other doesn’t gain and isn’t harmed
32
What is mutualism?
Both partners in a relationship gain
33
What is parasitism?
Where one organism in the relationship gains at the expense of the other
34
What is a pathogen?
Organisms or infectious agents which cause disease
35
Pathogenesis
The mechanism by which a disease is produced
36
Pathogenicity
Ability of an organism to cause disease
37
Virulence
The relative ability of a pathogen to cause disease
38
Infection
Invasion of microorganisms into a host
39
Infectivity
The ability of a microbe to enter, survive in and multiply in a susceptible host
40
Infectious disease
When infection leads to host damage and injury
41
Epidemic
Unusually high number of cases at a particular time | E.g. plague
42
Endemic
Always present | E.g. gonorrhoea
43
Pandemic
Worldwide E.g. influenza
44
Acute
Quick | E.g. measles
45
Chronic
Slow | E.g. tuberculosis
46
Specific
E.g. smallpox
47
Non-specific
E.g. wound infection
48
What is the chain of infection
Characteristics of the organism (pathogen) Portal of entry Reservoir Portal of Exit Mode of transmission Characteristics of the host
49
What are characteristics of the organism (pathogen)?
``` Type Ability to invade host Virulence Degree to which it causes disease Number of organisms ```
50
What are possible portals of entry
``` Eyes Mucous membranes Respiratory tract Placenta Breaks in host barriers ```
51
What are possible reservoirs?
Humans Animals Environmental surfaces
52
What are possible portals of exit?
``` Respiratory tract Genitourinary tract Gastrointestinal tract Skin/mucosal surfaces Placenta Blood ```
53
What are possible modes of transmission?
Direct contact Droplets Vectors Airborne
54
What are possible characteristics of the host?
Lack of effective resistance Changes in host defences Tissues destruction
55
What are possible sources of infection?
Endogenous: - from the host itself Exogenous: - from people (cases, carriers) - from animals (zoonoses) e.g. plague from rabies - from the environment e.g. legionella from water, tetanus from soil
56
What are the possible routes of spreading infection through horizontal transmission?
To other people: - airborne e.g. influenza, colds, TB - faecal-oral e.g. food poisoning, typhoid - sexual contact e.g. gonorrhoea, HIV - vectors e.g. mosquitos carry malaria - animals e.g. rabies Indirect transmission: -fomites
57
What are the possible ways of spreading infection through vertical transmission?
Mother to child e.g. HIV, rubella
58
What are possible virulence factors?
``` Adhesins Bacterial toxins - exotoxins and endotoxins Invasiveness Cell damage Avoid immune response ```
59
Describe exotoxins
May be the principal cause of disease Proteins produced by gram positive and gram negative bacteria Many consist of a number of subunits Secreted into the extracellular space Differing modes of action - cytotoxic, enterotoxic, neurotoxic
60
Describe clostridium and clostridial neurotoxins
Anaerobic, spore forming organisms Ubiquitous in the environment Very potent molecules Affect peripheral nervous system Clostridium botulinum causes botulism. It produces one of seven toxins - A B C D E F G (BoNT/A and so on) Clostridium tetani causes tetanus (lockjaw). It produces one toxin - TeNT
61
Describe tetanus
Can be neonatal and maternal Results from wound infection Causes muscle rigidity and spasm
62
Describe botulism
Caused by food poisoning - ingestion of pre formed toxin Caused by wounds - introduction of spores Infant botulism can occur Causes descending flaccid paralysis In babies it results in a failure to feed
63
Describe the structure of a neurotoxin
It is a tripartite toxin - it has 3 parts: The protease which is the active subunit The translocation unit The binding domain
64
How does botulism result in flaccid paralysis?
The BoNTs act at the neuromuscular junction
65
How does tetanus cause muscle spasms and then paralysis?
TeNT enters at the neuromuscular junction and is transported to the spinal cord where it acts within inhibitory interneurons
66
What are possible toxin modifications?
Chimera - results in binding to different target cells Delivery vehicle - causes inactivated protease. Carry drugs or other molecules into cells Non paralytic - enters central neurone

Medical Sciences (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions