Chapter 8

Question 1

General characteristic of protist

Answer 1

eukaryotic (true nucleus), unicellular, size: 5 μm to 5 mm

Question 2

Medical significance of protists

Answer 2

some protists produce toxins that do not harm oysters, but do harm humans. They can be parasitic, like malaria and toxoplasmosis. Some can reproduce very quickly and produce blooms that can block sunlight.

Question 3

3 types of protist

Answer 3

plant like, fungi like, animal like

Question 4

Plant-like

Answer 4

Carry photosynthesis - euglenoids, diatoms, dinoflagellates. Can be deadly toxins.

Question 5

Fungi-like

Answer 5

Decomposers - water molds - related to brown algae and diatoms. Causes disease in fish and other aquatic organisms. Slime molds: parasite of algae, fungie, plants

Question 6

Animal-like

Answer 6

Some commensals
Some parasitic (giardia and amoebozoa, both causing diarrhea)

Question 7

General characteristics/significance of fungi

Answer 7

Decomposers - digest dead organisms. All fungi have lysosomal enzymes that digest damaged cells and help parasitic fungi to invade hosts. Never an obligate parasite because all fungi can obtain nutrients from dead organisms. Antibiotic producers: inhibit the growth of other organisms. Pathogens.
Fungal parasites: extensive crop damage (wilting), economic losses from mildews. Ginormous size.
Takes very long time to grow, so diagnoses take a while.
Antibiotics are not for fungal infections, anti parasites are.

Question 8

4 Types of mycoses and how to identify them in a clinical story

Answer 8

Superficial: skin, hair, nails
Subcutaneous: deeper skin layers and lymph vessels
Systemic: internal organs
Opportunistic: when host defenses are impaired.

Question 9

Parasitology - general characteristics of a parasite

Answer 9

Organisms that live at the expense of a host, and vary in degree of damage caused, if they cause disease they are called pathogens.

Question 10

Classification of parasites

Answer 10

Based on the location and relationship to the host (ecto and endoparasites)
Based on the part of the cell cycle needed to be spent in/on the host (obligate and facultative parasites)
Based on the time they need to stay within the host (permanent, temporary, and accidental parasites)

Question 11

Ectoparasites

Answer 11

live on surface of other organisms (ticks and lice)

Question 12

Endoparasites

Answer 12

live within the bodies of other organisms (worms)

Question 13

Obligate parasites

Answer 13

must spend some of their life cycle in a host (like the protozoan that causes malaria)

Question 14

Facultative parasites

Answer 14

(soil fungi) normally free living, but they can obtain nutrients from host

Question 15

Permanent parasite

Answer 15

remain in or on host once they have invaded it (tapeworms)

Question 16

Temporary parasite

Answer 16

feed on and then leave their host (biting insects)

Question 17

Accidental parasite

Answer 17

invade an organism other than their normal host (dog ticks)

Question 18

vectors

Answer 18

an organism that transfers a parasite to a new host. Agents of transmission

Question 19

3 types of vectors

Answer 19

biological vector, mechanical vector, and hyperparasitism

Question 20

Biological vector

Answer 20

vector in which the parasite goes though part of its life cycle. The malaria mosquito is both a host and a biological vector.

Question 21

Mechanical vector

Answer 21

a vector in which the parasite does not go through any parts of its lifecycle. Flies that carry parasites eggs, bacteria, viruses from feces to food.

Question 22

Hyperparasitism

Answer 22

when parasites have parasites. Mosquitos which are temporary parasites harbor the malaria parasite

Question 23

2 types of reproduction for parasites

Answer 23

Schizogony and hermaphrodite

Question 24

Schizogony

Answer 24

Multiple fission in which on cell gives rise to many cells

Question 25

Hermaphrodite

Answer 25

One organism has both female and male reproductive systems and both are functional

Question 26

ways that parasites can avoid the immune system

Answer 26

Encystment (shell) , Immunological changes (changing antigens – for example spikes), Host cell invasion (hiding inside host cells)

Question 27

Encystment (shell)

Answer 27

The formation of an outer covering that protects against unfavorable conditions
These resistant cyst stages also sometimes provide a site for internal organization and cell division, help attach parasite to a host or serve to transmit a parasite from one host to another

Question 28

Immunological changes (changing antigens – for example spikes)

Answer 28

Changing the parasite’s surface antigens faster than the host can make new antibodies causing the host’s immune system to make antibodies that cannot react with the parasite’s antigens

Question 29

Host cell invasion (hiding inside host cells)

Answer 29

Invading host cells, where the parasite is out of reach of host defense mechanisms (HIV)

Question 30

Other parasites

Answer 30

Worms – helminth
- Flatworms
– Longer
– Hermaphrodites
- Roundworms
– Shorter
– Females and males

Question 31

Other vectors

Answer 31

Arachnids, Insects, Crustaceans

Question 32

Arachnids

Answer 32

external parasites on many animals and serve as vectors.

Question 33

Insects

Answer 33

lice, fleas, certain flies: feed on humans directly or indirectly by carrying parasites

Question 34

Crustaceans

Answer 34

crayfish, crabs, copepods (transmitted by guinea worms)