Question 1

Which of the following is a defining characteristic of algae?

Accepted Answer

They lack roots, stems, and leaves.

Question 2

Which phylum of algae is harvested for agar and carrageenan and can live at greater depths than other algae?

Accepted Answer

Red algae

Question 3

Which of the following is a harmful effect of dinoflagellates?

Accepted Answer

They cause paralytic shellfish poisoning through neurotoxins.

Question 4

Which structure in multicellular algae provides buoyancy and allows the organism to float?

Accepted Answer

Pneumocyst

Question 5

Which of the following statements about protozoa is TRUE?

Accepted Answer

Protozoa are unicellular eukaryotes that may cause disease in humans.

Question 6

A patient presents with severe diarrhea after drinking untreated water while camping. Microscopy reveals cysts in the stool. Which protozoan is most likely responsible?

Accepted Answer

Giardia intestinalis

Question 7

Which of the following best describes the life cycle of Plasmodium spp. (malaria parasite)?

Accepted Answer

Sexual reproduction occurs in mosquitoes; asexual reproduction occurs in humans.

Question 8

Which of the following protozoa moves by means of pseudopods and can cause dysentery in humans?

Accepted Answer

Entamoeba histolytica

Question 9

Which of the following is a distinguishing characteristic of parasitic helminths compared to free-living helminths?

Accepted Answer

They have a reduced nervous system.

Question 10

A patient is diagnosed with a tapeworm infection after eating undercooked pork. Which structure allows the tapeworm to attach to the intestinal wall?

Accepted Answer

Scolex

Question 11

Which of the following nematodes is transmitted by eggs that are infective for humans and is commonly known as the pinworm?

Accepted Answer

Enterobius vermicularis

Question 12

Which of the following best explains why parasitic helminths often have complex life cycles involving multiple hosts?

Accepted Answer

To maximize reproductive success and transmission to new hosts.

Question 13

Which of the following is TRUE regarding the transmission of Toxoplasma gondii?

Accepted Answer

It is transmitted by ingestion of oocysts from cat feces.

Question 14

Which of the following arthropods is correctly matched with the disease it transmits?

Accepted Answer

Pediculus humanus (louse) – Epidemic typhus

Question 15

Which of the following statements about cestodes (tapeworms) is CORRECT?

Accepted Answer

They absorb nutrients through their cuticle.

Question 16

A patient presents with anemia after walking barefoot in contaminated soil. Which nematode is most likely responsible, and how does it enter the body?

Accepted Answer

Necator americanus; larvae penetrate the skin

Question 17

Which of the following best describes the difference between a definitive host and an intermediate host?

Accepted Answer

The definitive host is where sexual reproduction occurs; the intermediate host is where asexual reproduction occurs.

Question 18

Which of the following is a beneficial effect of algae?

Accepted Answer

They are used in the production of agar and algin.

Question 19

Which of the following protozoa is transmitted by the bite of a blood-feeding insect and causes African sleeping sickness?

Accepted Answer

Trypanosoma spp.

Question 20

Which of the following is a characteristic of the phylum Apicomplexa?

Accepted Answer

They are nonmotile, obligate intracellular parasites.

Algae, Protozoa, Helminths, and Arthropod Vectors: Key Concepts in Medical Microbiology

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