Topic 9 -Parasites

Question 1

What is the difference between ecto and endoparasite?

Answer 1

Ecto - on the host

Endo - in the host

Question 2

What are the classifications of parasites?

Answer 2

1. Protozoa
2. Nematoda
3. Platyhelminthes
4. Arthropoda

Question 3

What are examples of protozoa?

Answer 3

Amebae, flagellates, coccidia, sporozoans and microsporidia.

Question 4

What are examples of nematodes?

Answer 4

Roundworms

Question 5

What are examples of platyhelminthes?

Answer 5

flatworms, cestodes and trematodes

Question 6

What are protozoan characteristics?

Answer 6

Trophoziote (vegetative state), sexual reproduction by conjugation, produce cysts and asexual is through fission/budding or schizogony.

Question 7

What protozoans cause disease?

Answer 7

Giardia lamblia (cyst) and Trichomonas vaginalis (not cyst stage)

Question 8

What are helminths?

Answer 8

Parasitic worm in the animalia kingdom. There are two phylums:

• platyhelminths = flat worms and the classes include = traematodes (flukes) and cestodes (tapeworms).
• Nematodes = roundworms

Question 9

What are helminth characteristics?

Answer 9

1. Reduced digestive system
2. Reduced nervous system
3. Reduced locomotion
4. Complex reproduction

Question 10

What is the life cycle of helminths?

Answer 10

Egg —-> Larvae —-> Adult

Question 11

What is the difference between monoecious and dioecious?

Answer 11

Monoecious is a hermaphrodite which means it has both male and female reproductive systems in one animal while dioecious have separate male and female parts.

Question 12

What is a definitive host?

Answer 12

A host where adult stage of parasite emerges and produces eggs that are passed onto intermediate host

Question 13

What is an intermediate host?

Answer 13

A host where parasite can’t produce eggs in

Question 14

What are virus characteristics?

Answer 14

1. Intracellular parasites
2. Contain DNA and RNA
3. Protein coat
4. Some have spikes

Question 15

What is the virion structure?

Answer 15

• Nucleic acid, either DNA or RNA never both
• Capsid, made up of capsomeres
• Envelope, spikes may protrude from envelope and envelope is host-cell derived

Question 16

What are bacteriophages?

Answer 16

Viruses that are pathogenic to bacteria

Question 17

What is the structure of the virion structure?

Answer 17

• Head
• Sheath
• Baseplate
• Tail

Question 18

What is T-even mean?

Answer 18

Bacteriophage will have an even number

Question 19

What is a T4 bacteriophage?

Answer 19

A complex virus which is non-enveloped

Question 20

What is the taxonomy of viruses?

Answer 20

Family = -viridae
Genus = -virus
Species = common names
Subspecies = number

Question 21

What is a plaque?

Answer 21

A clearing in bacterial lawn caused by bacterial colony lysis.

Question 22

What does embryonted egg mean?

Answer 22

A fertilised egg

Question 23

Animal viruses can grow in living animals but not embryonated eggs. True or False?

Answer 23

False, they can grow in both

Question 24

What are the step with growing viruses in cell cultures?

Answer 24

1. Treat tissue with enzyme to separate cells
2. cells suspended in culture medium
3. Transformed or continous cell cultures dont grow in a monolayer

Question 25

How is the viral one step curve different then bacterial growth?

Answer 25

Bacterial growth has a lag, log, stationary and death phase

Question 26

What are virus identifications?

Answer 26

1. Cytopathic effects 2. Serological tests 3. Nucleic acid

Question 27

What is the lytic cycle?

Answer 27

1. Attachment - phage attaches by tail fiber to host cell 2. Penetration - lysosome opens cell wall and sheath contracts and forces DNA into cell 3. Biosynthesis - production of DNA and proteins 4. Maturation - assembly of phage proteins 5. Release - lysosome breaks cell wall

Question 28

What is the result of bacteriophage multiplication?

Answer 28

lytic cycle - causes death of host cell | lysogenic cycle - incorporates DNA into host DNA, phage conversion and specialized transduction

Question 29

What are the life cycles of animal viruses?

Answer 29

``` Attachment Penetration Uncoating Biosynthesis Maturation Release ```

Question 30

What are plant viruses and viroids?

Answer 30

PV - enter through wounds or insects | Viroids - Infectious RNA

Question 31

What is parasitism?

Answer 31

A symbiont that lives/harms at the expense of another organism. This relationship involves the host and the parasite. It may result in disease.

Question 32

What are prion diseases caused by?

Answer 32

An aberrant form of a naturally occuring protein PrP

Question 33

Why are prion diseases different to other diseases?

Answer 33

It's the first transmissible disease without a nucleic acid being involved which is different to viruses and bacteria

Question 34

What is a normal cellular prion? What causes plaques?

Answer 34

PrPc | PrPsc

Question 35

What is the post mortem appearance of a prion?

Answer 35

Large vacuoles in cortex and cerebellum, known as spongiform encephalopathies

Question 36

What are transmissible forms of prion diseases?

Answer 36

``` TME CWD BSE vCJD Scarpie ```

Question 37

What are inherited forms of prion diseases?

Answer 37

CJD GSS FFI Kuru