Causes of Infection

Question 1

What are the main agents causing infection?

Answer 1

Bacteria
Virus
Fungi
Parasites
Prions

Question 2

What factors allow infection to occur?

Answer 2

Barriers to infection

Enviroment

Question 3

Describe structure of a virus?

Answer 3

Small, metabollically inert, too small, have different shapes

Question 4

What do viruses need for the cells to replicate?

Answer 4

Living host cells

Question 5

What are the components of a virus?

Answer 5

Cell wall, Core, Sheath, Capsid, Genes

Question 6

What is a Capsid on a virus?

Answer 6

Protein coat - a shell that stays out out of body

Question 7

What can some viruses derive from a host cell?

Answer 7

Lipid envelope

Question 8

What does a Virus contain?

Answer 8

Genetic material but no organelles

Question 9

What do Virus’s rely on?

Answer 9

Host organelles/systems to reproduce

Question 10

How do Viruses bind to a cell?

Answer 10

Use surface proteins to insert genetic material inside

Question 11

What are 3 Common viruses?

Answer 11

Chickenpox virus - lay dormant emerge to cause shingles
Rhinovirus - infect for days cause a cold
Hep C virus- Chronic liver infection over years

Question 12

How do Viruses differ in the severity of diseases?

Answer 12

Mild - herpes
Variable - flu
Severe - Ebola

Question 13

Describe structure of bacteria?

Answer 13

Prokaryote
Unicellular
Cell membrane,cell wall, no nucleus, asexual, move using flaggells

Question 14

What genetic material would be in bacteria?

Answer 14

DNA but no membrane

Question 15

What are the 3 shape classifications of bacteria?

Answer 15

Coccus - circle
Spirillum - spiral
Bacillus - rod

Question 16

What are the 3 cell wall stain classifications?

Answer 16

Gram positive
Gram negative
Others i.e myobacteria

Question 17

Describe Gram negative?

Answer 17

Lipopolysaccharide and protein on outer chell , stains pink

Question 18

Describe Gram positive?

Answer 18

Simple membrane and peptidoglycan - stains purple

Question 19

What does the type of cell wall in bacteria determine?

Answer 19

Structural strength of cell and how well it can survive in the enviroment

Question 20

What is the format of the names of bacteria?

Answer 20

Family then type, always in italics, Family first letter always capital second type always lowercase

Question 21

What are 4 examples of bacterial diseases?

Answer 21

Meningoccocal sepsis (blood)
Bacterial endocarditis
Cellulitis
Streptococcal throat infection

Question 22

Describe Fungi?

Answer 22

Eukaryotes, similiar characteristics to human cells reproduce asexual and sexually

Question 23

What are 3 types of fungi?

Answer 23

Yeasts - candida albicans
Moulds - aspergillus fumigatus
Diamorphic fungi - switch between types

Question 24

Give examples of Mild fungal infections?

Answer 24

Thrus, athletes foot, ringworm

Question 25

Give example of severe fungal infections?

Answer 25

Cryptococcal meningitis in HIV | Invasive candida in ICU

Question 26

What are the 3 types of parasites?

Answer 26

Ectoparasites - out of body i.e ticks Endoparasites - inside body - worms Epiparasites - live on another parasite i.e malaria on mosquitos

Question 27

What are the 2 general classes of human parasites?

Answer 27

Unicellular organisms - protozoa | Worms - helminths

Question 28

Describe the Parasitic disease Giardia?

Answer 28

Cause bloody diarrohoea Caught from drinking infected water can be seen in stool in microscope cyst forms and spreads

Question 29

Describe the parasitic disease malaria?

Answer 29

Biggest killer complex reproduce in female mosquitos Infect human RBCS

Question 30

What are the 4 types of malarial parasite?

Answer 30

Falciparum - most severe Chloroquine sensitive malaria Chloroquine resistant malaria Multi resistant malaria

Question 31

What are the 3 types of worms?

Answer 31

Cestodes - tapeworms flat Trematodes - flukes - flat Nematodes - round, cylindrical teeth

Question 32

Describe Cestodes?

Answer 32

Tapeworms can be found in a variety of protein inc sushi

Question 33

What diseases can Cestodes cause?

Answer 33

Malabsorption Malnutrition Cysts in muscle or brain

Question 34

Describe Nematodes?

Answer 34

Biggest - round worms

Question 35

What problems can Nematodes cause?

Answer 35

Elephantiasis Diarrohoea Malabsorption

Question 36

Describe Trematodes?

Answer 36

Flukes in lung liver parncreas intestinal

Question 37

What type of Fluke is Schistosoma from?

Answer 37

Blood flukes, 2nd most parasitic disease for death

Question 38

How does Blood flukes get into the body?

Answer 38

From fresh water snails, flukes pentrate skin

Question 39

What are Symptons of schistosoma?

Answer 39

Migrate to veins, diarrhoea, fever, abdominal pain

Question 40

What are Prions?

Answer 40

Smallest infective agents

Question 41

What are prion particles called?

Answer 41

Proteinaceious infection particles

Question 42

Describe structure of prions?

Answer 42

Lack nucleic acid, not living, proteins fold abnormally accumulate in neural tissue, VERY difficult to destroy

Question 43

What are the concerns of removing Prions?

Answer 43

Cleaning surgical instruments

Question 44

What are some examples of Prion diseases?

Answer 44

CJD - fatal degenerative neurological disease, Variant in young adults, BSE in cows, Scrapie in sheep, Kuru spread by cannibalism

Question 45

What are the defence mechanisms in the body against infection?

Answer 45

Skin, Mucous membrane, Stomach acid, microflora, Immune system