Week 8

Question 1

Define symbiosis

Answer 1

To live together in a relationship which is mutually beneficial to the host and the microbe, or harmful to the host.

Question 2

Define mutualism

Answer 2

Both members benefit from the symbiotic relationship and in some cases need each other for survival.

Question 3

Define commensalism

Answer 3

One of the organisms in he symbiotic relationship benefits without affecting the other.

Question 4

Define parasitism in terms of symbiosis.

Answer 4

A parasite benefits from its host without harming it

Question 5

What type of relationships do microbiota in the normal flora have with the body?

Answer 5

Mutualistic and commensal

Question 6

How many different types of microbiota are in the normal human flora?

Answer 6

400-1000

Question 7

What are the 2 types of Indigenous microbiota?

Answer 7

Resident microbiota

Transient microbiota

Question 8

What are indigenous microbiota?

Answer 8

They reside inside the body but rarely cause disease.

Question 9

What are resident microbiota?

Answer 9

They are specially adapted t live in the body and are unique to each individual.

Question 10

What is the main function of resident bacteria?

Answer 10

Compete out foreign bacteria.

Question 11

How long can transient microbiota survive in the body for ?

Answer 11

Hours to months

Question 12

Why can’t transient microbiota survive in the body long term?

Answer 12

There is alot of competition from other microorganisms.

They are often eliminated by the body’s immune system.

Affected by chemical and physical changes in the body.

Question 13

What are opportunistic pathogens?

Answer 13

An infection caused by a pathogen that takes advantage of an opportunity that is not usually available.

Question 14

Give examples of circumstances which may allow opportunistic pathogens to cause disease.

Answer 14

Immune suppression
Changes in normal microbiota
Incorrect location

Question 15

Describe the presence of microbiota in the nose

Answer 15

Very unique microbiota because it is cooler than the rest of the respiratory system.

Question 16

Describe the presence of microbiota in the trachea and bronchi

Answer 16

Sparse

Question 17

Describe the presence of microbiota in the alveoli

Answer 17

No microbiota present

Question 18

Describe the presence of microbiota in the vagina

Answer 18

Change as acidity changes in the vagina during the menstruations cycle.

Question 19

Why can’t extensive colonisation of microbiota occur at the urethra?

Answer 19

The flow of urine prevents this

Question 20

Why are there few microbiota in the eyes compared to the skin?

Answer 20

They are washed away by tears.

Question 21

What prevents a foetus having any microbiota?

Answer 21

The presence of the amniotic fluid and use of the mothers immunity.

Question 22

When the amniotic sac breaks, how does microbiota enter a baby?

Answer 22

Enters the mouth and nose of the baby via the birth canal.

Question 23

At what stage can microbiota begin to enter the intestines of a baby?

Answer 23

Once it has consumed its first meal.

Question 24

How quickly are resident microbiota established on a human body?

Answer 24

Within the first months of life

Question 25

Define Pathogenicity

Answer 25

The ability to cause disease

Question 26

Define Virulence

Answer 26

A measure of pathogenicity

Question 27

Define contamination

Answer 27

The mere presence of microorganisms in or on the body.

Question 28

Define infection

Answer 28

Invasion of the body by a pathogen

Question 29

Define pathogen

Answer 29

A microorganism with the ability to cause disease.

Question 30

What are virulence factors?

Answer 30

A variety of traits that interact with a host and enable the pathogen to enter, adhere, gain access to nutrients and escape detection from the immune system.

Question 31

What are the events of infection?

Answer 31

Exposure to the pathogen. Adhere to skin or mucosa. Invasion through epithelium. Colonisation and growth. Tissue damage and disease.

Question 32

What are the possible portals of entry on the human body for a microorganism?

Answer 32

``` Broken skin Insect bite site Anus Urethra Vagina / Penis Placenta Mouth Nose Conjuctiva of eye Ear ```

Question 33

What are the main portals of entry for microbiota on the human body?

Answer 33

Mucous membranes

Question 34

What parts of the human body do mucous membranes cover?

Answer 34

All exposed body cavites

Question 35

What is meant by 'adhesion' in terms of macrobiotic infection?

Answer 35

Attachment to cells

Question 36

What are adhesions in bacteria?

Answer 36

Surface lipoproteins or glycoproteins the bin to host cell receptors.

Question 37

What type of molecule on the surfaces of microbiomes bind to host cells?

Answer 37

Lipoproteins or glycoproteins

Question 38

Where are adhesions in bacteria found?

Answer 38

In the Fimbriae and flagella

Question 39

What is created when bacteria colonise at a site?

Answer 39

A biofilm

Question 40

What is used to carry out invasion by microbiomes?

Answer 40

Extracellular enzymes or toxins

Question 41

What are the 2 categories of toxins?

Answer 41

Exotoxins and endotoxins

Question 42

Outline how Hyaluronidase and Collagenase enzymes invade host cells

Answer 42

Bacteria reach the epithelial surface of the host cells and release Hyaluronidase and Collagenase. These cause the epithelial cells to move apart and allow bacteria to invade deeper into the cell.

Question 43

Explain how bacteria use Coagulase and Kinase to aid infection.

Answer 43

Bacteria produce Coagulase which causes a clot to form on the edge of blood vessels. Bacteria then produce Kinase which dissolves the clot and releases bacteria into the blood stream.

Question 44

What are bacterial exotoxins?

Answer 44

They are secreted by the bacterial cell wall

Question 45

Give examples of bacterial exotoxins.

Answer 45

Cytotoxins Neurotoxins Enterotoxins

Question 46

What are bacterial endotoxins?

Answer 46

They are part of the bacterial cell all.

Question 47

Give an example of a bacterial endotoxin

Answer 47

LIPID A

Question 48

How do exotoxins from bacteria cause issues with host cells?

Answer 48

They directly kill host cells

Question 49

How do endotoxins from bacteria cause issues within host cells?

Answer 49

They induce effects such as fever, inflammation, diarrhoea, shock and blood coagulation.

Question 50

What is required for colonisation and growth of bacteria which have invaded a host?

Answer 50

Antiphagocytic factors

Question 51

Give examples of antiphagocytic factors

Answer 51

Capsules | Antiphagocytic chemicals

Question 52

What does the host's immune system use to fight invading microbiomes?

Answer 52

Phagocytes

Question 53

What is a capsule?

Answer 53

A layer of polysaccharide around a bacterial cell.

Question 54

Why do the capsules of Bacteria not trigger an immune response from host cells?

Answer 54

They have the same polysaccharides in their capsule as are found in the body naturally.

Question 55

What virulence factors are associated with exposure of the host to a pathogen during infection?

Answer 55

None

Question 56

What virulence factors are associated with adherence to skin or mucosa during infection?

Answer 56

Adhesins and biofilms

Question 57

What virulence factors are associated with invasion through epithelium during infection?

Answer 57

Extracellular enzymes and toxins

Question 58

What virulence factors are associated with colonisation and growth during infection?

Answer 58

Capsules and anti-phagocytic chemicals

Question 59

What are symptoms of disease?

Answer 59

They are subjective but frequently cause nausea.

Question 60

What are the signs of disease?

Answer 60

They are objective but can often be measured. | e.g. vomitting

Question 61

What is meant by the term 'syndrome'?

Answer 61

A group of signs and symptoms.

Question 62

What are the stages of infectious disease?

Answer 62

``` Incubation period. Prodromal period. Illness Decline Convalescence ```

Question 63

What is the incubation period of an infectious disease?

Answer 63

There are no signs and symptoms of the disease

Question 64

What does the length of the incubation period of an infectious disease depend on?

Answer 64

Virulence of pathogen. Infective disease. Host immunity. Site of infection.

Question 65

What is the incubation period of influenza ?

Answer 65

About 1 day

Question 66

What is the incubation period of AIDS?

Answer 66

1-8 years

Question 67

What is the incubation period of leprosy?

Answer 67

10 to 30 years

Question 68

How long does the prodromal period of an infectious disease last?

Answer 68

Short time

Question 69

What are the generalised symptoms of the prodromal stage of an infectious disease?

Answer 69

Malaise and muscle ache

Question 70

What is Malaise?

Answer 70

General feelings of discomfort or illness of which the exact cause is difficult t identify.

Question 71

Do all infections have a prodromal period?

Answer 71

No

Question 72

What is the most severe stage of infectious disease?

Answer 72

Illness

Question 73

What is happening during the 'illness' stage of an infectious disease?

Answer 73

The signs and symptoms are most evident and the patients immune system has not fully responded yet.

Question 74

What happens during the decline phase of infectious disease?

Answer 74

The patients body return to normal as the immune response or medical treatment defeats the pathogen. This causes symptoms to subside.

Question 75

In what stage of infection does the immune response peak ?

Answer 75

During define

Question 76

What is the 'convalescence' period of infection?

Answer 76

The patient recovers and tissues are repaired.

Question 77

What determines the length of time that the convalescence period of infection lasts?

Answer 77

Amount of damage caused. Nature of the pathogen. Site of infection. Overall well-being of the patient.