PARASITES

Question 1

parasite

Answer 1

live on/in an organism at detriment to the host

Question 2

pork tapeworm adaptations (3)

Answer 2

• ribbon-like, allowing food to move past it
• anterior end, scolex, made up of muscle-carrying suckers and hooks attaching to the duodenum wall
• body made up of proglottids allowing it to separate and reproduce

Question 3

what hosts does the pork tapeworm have? (2)

Answer 3

• primary host = human

- secondary host = pig

Question 4

how the tapeworm passes between hosts (2)

Answer 4

• pork infected by eating food contaminated by human faeces

- human infected by consuming undercooked, infected pork

Question 5

what hostile conditions must the tapeworm survive? (5)

Answer 5

• surrounded by mucus and digestive juices
• peristalsis produces constant movement
• pH changes when passing to the duodenum
• exposed to host immune system
• if the host dies, so does the parasite

Question 6

two types of parasite (2)

Answer 6

• endoparasite = lives inside organism

- ectoparasite = lives outside organism

Question 7

what does the tapeworm need to do? (7)

Answer 7

• penetrate host
• attach to host
• protect against immune response
• develop only organs necessary for survival
• produce many eggs, for a high chance of transmission (to the second host)
• have an intermediate host
• have resistant stages while away from the host

Question 8

tapeworm structural adaptations (7)

Answer 8

• suckers + double-row of curved hooks to attach to duodenum wall
• thick body covering, cuticle, to protect from immune response
• ability to make enzyme inhibitors, preventing host digesting
• large SA/V to absorb digested food
• no movement so simple nervous/excretery systems, reproduction priority
• hermaphrodite, proglottids containing male&female organs, pass out with faeces
• eggs have resistant shells to survive until in second host

Question 9

effects of the tapeworm (2)

Answer 9

• long-term infection leading to taeniasis - abdominal pains & weakness
• if infected eggs eaten directly, form cysts in organs inc. eyes and brain, damaging surrounding tissue

Question 10

tapeworm treatment/prevention (4)

Answer 10

• drugs
• education about cause
• improved sanitation
• frequent meat inspection

Question 11

headlice

Answer 11

• ectoparasite

- feed by sucking blood from scalp