4.1 Microbial Infection

Question 1

What are the five main types of infectious agents?

Answer 1

Viruses, bacteria, fungi, helminths, protozoa

Question 2

What is the definition of a virus?

Answer 2

Obligate intracellular parasite

Question 3

How do viruses reproduce?

Answer 3

By infecting a host cell and using their nuclear synthetic macheinery

Question 4

What can viruses infect?

Answer 4

All life forms, including bacteria

Question 5

What type of cell is a virus?

Answer 5

They are not cells in their own right

Question 6

What type of cells are bacteria?

Answer 6

Prokaryotes

Question 7

What type of organisms are fungi?

Answer 7

Eukaryotes - single cell

Question 8

What type of organisms are protozoa?

Answer 8

Eukaryotes - single cell

Question 9

What type of organisms are helminths?

Answer 9

Eukaryotes - multicellular

Question 10

What type of genetic material do viruses contain?

Answer 10

RNA or DNA

Question 11

How do viruses divide?

Answer 11

By budding out of the host cell or by cytolysis

Question 12

What are the four routes of infection that viruses can show?

Answer 12

Faecal-oral, airborne, insect vectors, blood borne

Question 13

What is an example of a virus and what type of genetic material does it have?

Answer 13

HIV – retrovirus so has RNA

Question 14

What do RNA genomes require in order to replicate?

Answer 14

Reverse transcriptase enzyme

Question 15

What is the difference between eukaryotes and prokaryotes?

Answer 15

Prokaryotes do not have internal membranes and therefore do not have membrane bound organelles

Question 16

Which bacteria has membrane bound organelles despite being a prokaryote?

Answer 16

Photosynthetic bacteria

Question 17

What is the genetic makeup of a prokaryotic organism?

Answer 17

Haploid – single copy of chromosome

Question 18

What is the difference in cytoskeleton between eukaryotes and prokaryotes?

Answer 18

Prokaryotes – cytoskeleton is poorly defined
Eukaryotes – well developed cytoskeleton

Question 19

What does the prokaryote cell wall contain?

Answer 19

Peptidoglycan

Question 20

How do prokaryotes divide?

Answer 20

Binary fission

Question 21

What structure of bacteria allows them to move?

Answer 21

Flagellum

Question 22

How does shigella spread?

Answer 22

Faecal-oral transmission

Question 23

How does shigella move around in the host?

Answer 23

Using host cell actin

Question 24

Which bacteria causes meningitis?

Answer 24

Neisseria Meningitidis when when it infects the CSF

Question 25

What is the result of septicaemia on the body?

Answer 25

Septic shock and a severe inflammatory response

Question 26

Which bacteria are commonly responsible for hospital acquired infections?

Answer 26

Clostridium difficile Methicilin resistant staphylococcus aureus

Question 27

Which bacteria causes peptic ulcers and gastric cancer?

Answer 27

Helicobacter pylori

Question 28

How is mycobacterium tuberculosis spread?

Answer 28

Airborne

Question 29

How do bacteria evolve so quickly?

Answer 29

They have similar mutation rates to humans, but reproduce more often, thus having a **shorter generation time**

Question 30

What three types of conditions can fungi cause?

Answer 30

Cuteanous, mucosal or systemic mycoses

Question 31

How do fungi occur as?

Answer 31

Yeasts, filaments or both

Question 32

How do fungi replicate? (yeasts vs filaments)

Answer 32

Yeasts bud or divide Filaments undergo fragmentation

Question 33

What is an example of an infectious fungi?

Answer 33

Candida albicans

Question 34

What are two characteristic features of filaments?

Answer 34

They have cross walls or septa

Question 35

How do protozoa replicate?

Answer 35

In the host by **binary fission** or by **formation of trophozoites** inside a cell

Question 36

How is a protozoa infection acquired?

Answer 36

Infection is acquired by ingestion or through a vector

Question 37

How many hosts does the protozoa life cycle involve?

Answer 37

2

Question 38

Where can protozoa pathogens be found?

Answer 38

Intestines, blood and tissue

Question 39

How does the pathogen which causes malaria replicate?

Answer 39

Plasmodium forms trophozoites inside the host cell

Question 40

How is Malaria infection acquired?

Answer 40

Mosquito vector

Question 41

What is the malaria belt?

Answer 41

The belt around the equator line in which the incidence of malaria is the highest – corresponds with high temperatures

Question 42

What condition does Leishmania species cause?

Answer 42

Leishmaniasis

Question 43

How is Leishmaniasis infection acquired?

Answer 43

Via sandfly vector

Question 44

How does the Leishmania species replicate to cause Leishmaniasis?

Answer 44

Formation of trophozoites inside a cell

Question 45

What type of disease is leishmaniasis?

Answer 45

Cutaneous and visceral

Question 46

What are three exmples of helminths?

Answer 46

Roundwords Flatworms Tapeworms

Question 47

How do helminths replicate?

Answer 47

Sexually via eggs Some are hermaphroditic (have both male and female reproductive organs)

Question 48

What type of transmission do helminths exhibit?

Answer 48

Faecal-oral transmission

Question 49

Which bacterial pathogen are metazoa?

Answer 49

Helminths – multicellular

Question 50

What type of worm are flukes?

Answer 50

Flatworms

Question 51

What disease do flukes cause?

Answer 51

Schistosomiasis

Question 52

Is there a vaccine against helminths?

Answer 52

Treatable, but no vaccine