Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Infection Term 4 > Infection Intro- 1.1. & 1.2 > Flashcards

Infection Intro- 1.1. & 1.2 Flashcards

(69 cards)

Start Studying
1
Q

What does the germ theory state?

A

Microorganisms are the cause of many diseases

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

What are the 7 types of microorganisms? ( BAPAFV)

A 
Bacteria 
Archaea
Protozoa
Algae 
Fungi 
Viruses 
- Multicellular animal parasites eg helminths
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

State Koch’s Postulates (4)

A

1) Microorganism must be observed in every case of the disease
2) Microorganism must be isolated and grown in pure culture
3) Pure culture, when inoculated in animals must reproduce the disease.
4) Microorganism must be recovered from the diseased animal.

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

What does phylogeny state? (BAE)

A

Bacteria, Archaea and Eucarya all come from the same universal ancestor

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

How do we classify organisms?

8

A

Determined Kind People Can Often Find Ghastly Screams

Domain 
Kingdom
Phylum
Class 
Order
Family 
Genus 
Species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What classification is used for viruses and how do you classify them?

A

BALTIMORE CLASSIFICATION

Classes 1-7

  • Classes 1 and 2 MUST replicate in the nucleus only
  • Classes 3 to 7 must replicate in the cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name the 5 shapes of bacteria

A

1) Spheres - cocci
2) Rods-bacilli
3) Spirals- spirilla
4) Comma- vibrios
5) Corkscrews- spirochetes

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

List differences between gram positive and gram negative bacteria

A
  • Gram positive bacteria have a peptidoglycan cell wall and stains PURPLE with gram
    -Gram negative bacteria has a cell wall with a thin layer of peptidoglycan and an
    OUTER MEMBRANE with a lipopolysaccharide
    it stains RED/PINK with gram
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do bacteria reproduce?

A

by BINARY FISSION

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

Describe Binary Fission

A
  • an organism duplicates its DNA and divides by cytokinesis

- this produces two identical daughter cells

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

What is the purpose of endospores for bacteria?

A

Help bacteria survive in hostile environments by allowing them to be encapsulated and desicated in them
-they are dormant structures and are resistant to physical and chemical conditions

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

Define infection

A

Growth of microorganism in a host, not synonymous with disease

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

Define a pathogen

A

An organism that causes damage to a host

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

Types of pathogens (3) (POZ)

A

Primary
Opportunistic
Zoonotic ( E.Coli)

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

Define Pathogenicity

A

ability of a microorganism to cause disease

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

Define Virulence

A

the degree of pathogenicity

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

Define Parasite

A

an organism that lives on or in a secondary organism called a host

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

How do opportunistic pathogens work?

A

they have the potential to cause disease with the right conditions

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

How do viruses replicate?

A

-the virus particle attaches to the host cell before penetrating it.
-uses the host cell’s machinery to replicate its own genetic material.
-after replication, the virus particles leave the host, by either:
budding
lysis; bursting out of the cell

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

Describe virus replication

A
  • viruses replicate by budding
  • newly formed viral particle pushes against the host cell’s plasma membrane, a portion adheres to it.
  • the virus is released from the cell by LYSIS
  • after escaping from the host cell, the virus can enter a new cell and multiply
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define virulence

A

A pathogen’s ability to infect or damage a host

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

What do virulence and pathogenicity depend on?

A

the composition of the genome

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

What is attenuation?

A

when a pathogen’s virulence is reduced eg in cultured conditions like VACCINES ( For small dose exposure)

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

What is ID5O?

A

Estimated number of organisms/ virus particles required to produce infection in 50% of normal adult humans exposed by a given route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Name the 3 functions of virulence factors | IEC
allow pathogen to: 1) Invade the host 2) Evade host defences 3) Cause disease
26
List the 5 functions of virulence factors | ACITI
1) Attachment- via adhesions 2) Colonisation- and enzymes 3) Invasiveness 4) Toxins-and enzymes 5) Inhibition of Phagocytosis
27
Define a toxin
Substances that contribute to pathogenicity
28
Define pathogenicity
ability to produce a toxin
29
Define toxaemia
presence of a toxin in the host's blood
30
Define toxoid
Inactivated toxin used in a vaccine
31
Define antitoxin
antibodies against a specific toxin
32
What are the two types of toxins?
Exotoxin- produced and secreted by bacteria | Endotoxin- within bacterial composition
33
Describe endotoxins
- gram negative bacteria - found in outer layer of gram negative bacteria ie lipid portion - Lipid A polysaccharide; highly antigenic and promotes a strong immune response
34
What is the endotoxin's mode of infection?
Upon digestion by microsome, the endotoxin's lipid fragments are expelled from the phagocyte -this induces inflammation, fever, endotoxic shock, diarrhoea and blood coagulation
35
What type of bacteria releases exotoxins?
both gram positive and gram negative bacteria | ALL MAJOR GRAM POSITIVES PRODUCE EXOTOXIN
36
What are the three types of exotoxins? ( based on mode of action)
Class I: disrupt pattern of communication of signalling at host cell membranes Class II: cause physical damage to cell membranes Class III: enter target cells and directly alter function
37
What are the three classes of toxins? (NES)
- Neurotoxins - Enterotoxins - Superantigens
38
Give two examples of neurotoxins
tetanus | botulinum
39
Give two examples of enterotoxins
staph aureus | cholera
40
What are enterotoxins?
exotoxins that act in the small intestine; cause a massive secretion of fluid into intestinal lumen
41
Give two examples of superantigens
TSST | Staphylococcal scalded skin syndrome
42
Describe superantigens
- Type 1 exotoxin ie disrupt pattern of communication within cells - cause an intense immune response due to release of cytokines from host cells eg TSST
43
What symptoms are caused by superantigens?
- fever - nausea - vomiting - diarrhoea - shock - death
44
Describe the interaction between superantigens and T cells
superantigen loses specificity and is bound to T cell irrespective of recognition -very heightened, multiple response to a generic stimulus
45
Describe TSST | and name three symptoms (HOD)
Toxic Shock Syndrome Toxin TSST-1 (TYPE 1 ENDOTOXIN) -Superantigen causes hypotension, desquamative skin lesions and organ dysfunction
46
Describe SSSS ( type 2; damage to membrane)
``` Staphylococcal Scalded Skin Syndrome -exfoliation toxin causes bullae and skin exfoliation, fever redness and lesions skin wrinkles and blisters ```
47
How do type 2 toxins work? give an example
Membrane disrupting toxins - lyse host's cells by making protein channels in the PM eg hemolysins, leukocidins - disrupting phospholipid bilayer eg Clostridium- gas gangrene -causes a change in supply of blood to an area and increased permeability in membrane and -increased blood flow and increased gas in tissue spaces
48
Describe structure of clostridia
- large - gram positive - bacilli (rods) - ANAEROBIC - spore forming - fermentative
49
What is Vibrio Enterotoxin? eg needed
vibrio cholera ( cholera toxin) A-B enterotoxin (1A 5B) - One of the B subunits binds to a glycoprotein receptor on membrane causing CLEAVAGE of unit - adenylyl cyclase converts ATP to cAMP - cAMP stimulates active secretion of electrolytes into intestinal lumen and water follows into intestine
50
Name some symptoms of cholera and how do you treat it?
watery diarrhoea- rice stools dehydration thirst metabolic acidosis because of loss of bicarbonate Treat with ORT- Oral Replacement Therapy and then with antibiotics only if necessary
51
Define Botulinum Toxin
caused by clostridium botulinum A-B neurotoxin 3 types (food-borne, infant and wound) METALLOPROTEASE toxin catalyses proteolysis of key proteins to block ACh release causing FLACCID PARALYSIS
52
How can botulinum be harmful?
death from respiratory paralysis
53
Mechanism of botulinum?
-toxin gets internalised into neuron by endocytosis and forms a toxin vesicle -toxin's light chain is released from vesicle into cytoplasm of nerve terminal -light chain blocks ACh release by cleaving components of SNARE complex ( binding complex of ACh) THEREFORE ACh cannot bind to membrane so not released into synaptic cleft and to the post-synaptic membrane ie no muscle contraction ie FLACCID PARALYSIS
54
What is tetanus toxin?
clostridium tetani A-B neurotoxin -found as spores in soil or GI tract of animals, which develop into GRAM POSITIVE bacteria; that multiply and produce tetanospasmin
55
What is the mechanism of tetanospasmin and what does it cause?
-binds to motor nerves, enters axons and travels to the body of the motor nerve in the spinal cord or brainstem via RETROGRADE INTERNEURON TRANSPORT - toxin migrates to synapse and binds to nerve terminals and stops release of neurotransmitters like GLYCINE and GAMMA-AMINOBUTYRIC ACID - causing increased chemical signals to motor nerves of muscles, causing continuous tightening and contractions and spasm - can travel via lymphatic system and bloodstream and have same effect elsewhere causes SPASTIC PARALYSIS ( flexors and extensors continuously contract)
56
Define microbiotica
community of microorganisms living in a specific environment
57
Define microbiome
entire collection of genome elements of specific microbiotica
58
What are the functions of the microbiome
- maintaining intestinal integrity+supporting barrier function - breaking down food - providing essential nutrients, vitamins and short-chain fatty acids eg BUTYRATE
59
What are the 4 dominant gut bacteria/phyla? | (FABP)
Firmicutes Bacteroidetes Actinobacteria Proteobacteria
60
What is vertical transmission?
acquisition of microbes directly from an organism's parents
61
What is horizontal transmission?
acquisition of microbes from sources other than direct parents eg environment or from non-parental conspecifics
62
How does vertical transmission occur?
seeding via exposure to: - mother's vaginal bacteria - mother's gut bacteria
63
What are the 4 ways vertical transmission happens via the vagina?
1) Onset of labour or rupture of membranes 2) GBS bacteria can travel up from vagina to amniotic fluid 3) GBS can also transfer as baby journeys down the birth canal 4) Aspiration into lungs
64
How does vertical transmission occur in the mother's gut?
exposed to GBS from contact with mother's faecal matter during birth
65
What is Group B Streptococcus?
belongs to PYOGENIC STREPTOCOCCI - STREP AGALACTIAE - gram positive - beta haemolytic bacteria -common in GI and GU tracts seen in pregnant women, infants, older adults
66
What happens to newborns with GBS?
- resp problems | - sepsis signs; large patches of red raw skin
67
Name 3 obstetric risk factors for early onset GBS (PPI)
Preterm delivery Prolonged rupture of membranes Infection of placental tissues/amniotic fluid
68
Name other risk factors for early onset GBS
- GBS in mother's urine during pregnancy - previous infant with GBS disease - low maternal levels of anti-GBS antibodies - African American - young maternal age
69
What is dysbiosis?
persistent imbalance of gut's microbial community relates to many diseases (alteration of gut microbiotica composition) eg IBD IBS Celiac disease Colorectal cancer

Infection Term 4 (8 decks)

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