phylum nematoda

Question 1

two groups of protostomes

Answer 1

lophotrochozoa and ecdysozoa

Question 2

characteristics of ecdysozoa (2):

Answer 2

1. periodically moult exoskeleton

2. no motile cilia or flagella

Question 3

nematodes only have ____ muscles

Answer 3

longitudinal

Question 4

nematodes grow by:

Answer 4

the enlargement of cell size

eutely - fixed number of cells

Question 5

cilia (aberrant) of nematodes are restricted to:

Answer 5

seonsory structures

Question 6

why is the intestine of nematodes collapsed?

Answer 6

because of the high pressure pseudocoel

Question 7

movement in nematodes occurs because of (3):

Answer 7

1. stiff cuticle - resists tension
2. high pressure fluid filled pseudocoel
3. longitudinal muscles only

Question 8

feeding in nematodes

Answer 8

sucking by triradiate muscular pharynx

- myoepithelial cells contract, lumen opens and food/fluid is drawn in

Question 9

asexual reproduction in nematodes occurs by:

Answer 9

parthenogenesis (very few species)

Question 10

sexual reproduction in nematodes:

Answer 10

most are dioecious

- internal fertilization - males have copulatory spicules, aflagellate ameboid sperm

Question 11

how many moults do nematodes undergo

Answer 11

4

Question 12

facultative diapause occurs in:

Answer 12

dauer larva

Question 13

facultative diapause occurs after larval stage __ and is triggered by ____

Answer 13

two; environmental cues

Question 14

in facultative diapause, when conditions improve, the larva moults to larval stage ___

Answer 14

four; skips larval stage 3

Question 15

hookworm (parasitic nematode) has how many hosts?

Answer 15

one - human

Question 16

life cycle of hookworms

Answer 16

eggs passed in feces, moist soil, human with bare feet in moist soil – penetrates skin, travels to heart, lung - alveoli , then into intestine of human host

Question 17

hookworms use teeth elaborated from ___ to grab onto the wall of the small intestine

Answer 17

cuticle

Question 18

the parasitic nematode wuchereria bancrofti causes which disease?

Answer 18

elephatiasis (lymphatic filariasis)

- clogging of lymphatic vessels

Question 19

the parasitic nematode wuchereria bancrofti has how many hosts?

Answer 19

2 hosts: human and mosquito

Question 20

parasitic nematode - golden nematode has how many hosts?

Answer 20

one host - potato

Question 21

what are the ‘cysts’ on roots of potatoes infected by the golden nematode?

Answer 21

dead,swollen bodies of females filled with eggs

Question 22

caenorhabditis elegans is a model organism for:

Answer 22

developmental genetics