Ch. 18 Phylum Nematoda

Question 1

What are the general characteristics of Phylum Nematoda ?

Answer 1

cylindrical -shape
only longitudinal muscles
non-living cuticle
eutely

Question 2

What is the significance of C. elegans

Answer 2

There an important model for studies of genomics, development, cell differentiation

Question 3

How does the lack of circular muscles affect the movement of Nematodes?
a. It results in slow and sluggish movement.
b. It prevents them from burrowing into the soil.
c. It produces a characteristic thrashing motion.
d. It allows them to move in a straight line only.

Answer 3

c. It produces a characteristic thrashing motion.

Question 4

What is the difference in how the metabolism of parasitic and free-living nematodes ?
How does the metabolism of parasitic nematodes differ from that of free-living nematodes?
a. Parasitic nematodes rely solely on photosynthesis for energy.
b. Free-living nematodes have anaerobic metabolism.
c. Parasitic nematodes use glycolysis instead of full cellular respiration.
d. Free-living nematodes lack mitochondria.

Answer 4

c. Parasitic nematodes use glycolysis instead of full cellular respiration.

Parasitic - anaerobic, use glycolysis and other electron transport processes

free-living- aerobic

Question 5

How does the high hydrostatic pressure inside female roundworms affect repro.?
a. It prevents fertilization from occurring.
b. It facilitates the transfer of sperm from males to females.
c. It causes the eggs to develop inside the female’s body.
d. It increases the number of offspring produced.

Answer 5

b. It facilitates the transfer of sperm from males to females.

Question 6

What are the characteristics of Ascaris worms (life cycle)?

Answer 6

Host swallows embryonated eggs–>juveniles hatch, burrow in intestine walls—>travel to lungs, carried up to the trachea ->coughed up/swallowed —>mature in intestines, feed on it, perforating it

Question 7

What are the characteristics of Hookworms?

Answer 7

hook-like curve front end
plates in mouth that cut into intestinal lining
suck host’s blood
cause anemia
eggs pass through feces, hatch in soil
travel to lungs —>coughed up swallowed, mature in intestine

Question 8

What are the characteristics of Trichinella ?

Answer 8

cause trichinosis (tiny worms)
juveniles penetrate skeletal muscle cells
host’s cell becomes a nurse cell to the parasite

poorly cooked meat w/encysted juveniles
mature in intestines

Question 9

What are the characteristics of Pinworms ?

Answer 9

adult live in host intestine
males migrate to anal region at night, lay eggs, cause itching
eggs develop fast, infect in 6hrs at body temp.
swallowed, hatch, mature in intestines

Question 10

What are the characteristics of Filarial worms?

Answer 10

8 infect humans
Wuchereria bancrofti/ Brugia Malayi
cause inflammation, blockage of lymph vessels
juveniles microfilaria, released into blood/lymph
injected by mosquitos
worms move into new human host when it bites

Question 11

Which nematode parasite is responsible for causing trichinosis?
a. Ascaris lumbricoides
b. Hookworms
c. Trichinella
d. Pinworms

Answer 11

c. Trichinella

Question 12

Which nematode parasite is most common in the United States and causes itching around the anal region?
a. Ascaris lumbricoides
b. Hookworms
c. Trichinella
d. Pinworms

Answer 12

d. Pinworms

Question 13

Which nematode parasite is carried by mosquitoes and infects the lymphatic system of humans?
a. Ascaris lumbricoides
b. Hookworms
c. Trichinella
d. Filarial worms

Answer 13

d. Filarial worms

Question 14

Which nematode parasite causes elephantiasis?
a. Ascaris lumbricoides
b. Hookworms
c. Trichinella
d. Filarial worms

Answer 14

d. Filarial worms

Question 15

Which of these parasites does NOT enter the mouth of its human host and leave as eggs with the human feces?
Tapeworm
Pinworm
Ascaris
Hookworm
None of the choices are correct

Answer 15

Hookworm

Question 16

The name “hookworms” is due to the fact that they

Cluster in blood vessels in the liver and clog the veins
Burrow constantly through muscle tissues
Hook onto the intestine and consume blood and tissue fluids causing anemia
Clog the lymph glands and expand the legs and arms
Have an anterior end that curves dorsally like a hook

Answer 16

Have an anterior end that curves dorsally like a hook

Question 17

Which of the following statements is NOT correct about nematodes?
There are three layers of tissues in the body
Nematodes lack circular muscles under the tegument
The body cavity provides a hydrostatic skeleton
Nematodes have a smooth unsegmented outside body wall
Nematodes are all carnivores but may be free-living or parasitic

Answer 17

Nematodes are all carnivores but may be free-living or parasitic

Question 18

Elephantiasis is an enlargement of legs, arms, scrotum, and other tissues caused by
An infection of the human coelom by Ascaris
A large number of Trichinella worms encysting in human muscles
Contracting a disease that usually occurs in elephants
Microscopic nematodes that reproduce and clog lymph glands, causing infection and limbs to swell
A protozoan that lives in tropical roundworms and which, when ingested by humans, causes muscles to bloat

Answer 18

Microscopic nematodes that reproduce and clog lymph glands, causing infection and limbs to swell

Question 19

The nematode Coenorhabditis elegans has allowed scientists to develop “fate maps” tracing cell lines back to cell origins. The trait of nematodes and some other related groups where they have a set number of cell divisions leading to the same number of body cells in an adult is called
Anisogamy
Apoptosis
Cryptobiosis
Gastrulation
Eutely

Answer 19

Eutely

Question 20

Dogs commonly suffer from heartworm caused by
Dirofilaria, a filarial nematode
A tapeworm consumed in raw meat
Eating raw meat infected with Trichinella
Nematodes consumed as eggs in contaminated water
None of the choices are correct

Answer 20

Dirofilaria, a filarial nematode

Question 21

Elephantiasis is transferred by
Eating uncooked elephant meat
Worms burrowing into skin of feet
Drinking contaminated water or food
Mosquitoes injecting larval worms into the bloodstream
Exchanging body fluids with an infected person

Answer 21

Mosquitoes injecting larval worms into the bloodstream

Question 22

How do you become infected with hookworms (Necator americanus)?
You consume contaminated water or food
You eat uncooked meat
Larvae burrow into your feet
Mosquitoes inject them into your bloodstream
You transfer them from your anal region if you don’t wash your hands

Answer 22

Larvae burrow into your feet

Question 23

Juvenile Trichinella worms encyst in the
Liver
Lungs
Intestines
Lymph glands
Skeletal muscle

Answer 23

Skeletal muscle