1) Parasites and Parasitism. Interactions between parasites and hosts.

Question 1

what is parasitism?

Answer 1

the relationship between two species where the parasite benefits at the expense of the host, sometimes without killing it. It uses the host for nutrition and habitat.

Question 2

what is a host?

Answer 2

a living cell invaded by or capable of being invaded by a parasitic organism.

Question 3

what are the type of hosts?

Answer 3

• primary/definitive host
• secondary/intermediate host
• vector
• reservoir host

Question 4

define definite host

Answer 4

a host where the parasite can mature or reproduce sexually

Question 5

define intermediate host

Answer 5

a host where the parasite can reproduce asexually and some developmental stages can take place

Question 6

define vector

Answer 6

here the parasite can complete its life cycle and get transmitted to another host

Question 7

define reservoir host

Answer 7

a host where the parasitic presence and multiplication causes no harm

Question 8

what is a parasite?

Answer 8

an organism that obtains nourishment and shelter on another organism

Question 9

how are parasites divided?

Answer 9

• according to their dependance on a host
  -according to their location

Question 10

give the types of parasites according to dependance on a host

Answer 10

• obligatory parasite
• temporary parasite
• facultative parasite

Question 11

what is an obligatory parasite?

Answer 11

parasite that can only survive in a host

Question 12

what is a temporary parasite?

Answer 12

a parasite that spend half of its life in a host and half free living

Question 13

what is a facultative parasite?

Answer 13

a parasite that is usually free living and infects hosts accidentally

Question 14

give the type of parasites according to their location

Answer 14

• extracellular
• intracellular
• ectoparasites
• endoparasites

Question 15

what is an extracellular parasite?

Answer 15

a parasite that lives in the extracellular space of the host

Question 16

what is an intracellular parasite?

Answer 16

a parasite that lives within the host’s cells

Question 17

what is an ectoparasite?

Answer 17

a parasite that lives on the surface of the host

Question 18

what is an endoparasite?

Answer 18

a parasite that lives within the host

Question 19

give the different forms of parasites

Answer 19

• pathogenic
• commensal
• invasive

Question 20

what is a pathogenic parasite?

Answer 20

a parasite that causes symptoms of a disease

Question 21

what is a commensal parasite?

Answer 21

a parasite that doesn’t cause illness

Question 22

what is an invasive parasite?

Answer 22

a parasite that has the ability to spread to other hosts

Question 23

how do you name a parasitic disease?

Answer 23

name of parasite + -osis/-asis

e.g:
trypanosoma –> trypanosomiasis
trichomonas –> trichomoniasis

Question 24

what effects can parasites have on hosts?

Answer 24

• tissue damage
• toxic/allergic effect
• nutrition deficiency
• carcinogenic effect

Question 25

give the ways a parasite can invade a host

Answer 25

• peroral
• percutaneous
• transmissive
• transplacental
• sexual intercourse

Question 26

peroral invasion

Answer 26

a parasite that invades a host by food/water contamination

Question 27

percutaneous invasion

Answer 27

a parasite invades a host by penetrating the skin

Question 28

transmissive invasion

Answer 28

a parasite invades a host by an insect vector

Question 29

transplacental invasion

Answer 29

a parasite invades a host from a pregnant mother to a fetus