biology : class12 Sporozoite Inoculation : Causative Organism, Plasmodium, Life Cycle, Symptoms, Prevention : Malaria MCQ Questions and Answers
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Sporozoite Inoculation
MCQ questions and answers.
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MCQ Questions
1. During the bite of an infected female Anopheles mosquito, which Plasmodium stage is directly inoculated into the human host?
A.
Gametocyte
B.
Sporozoite
C.
Merozoite
D.
Ookinete
Correct Answer:
Sporozoite
Explanation:
Sporozoites are the infective stages for humans and are released from the mosquito's salivary glands into the host during the bite.
2. The sporozoites responsible for initiating malaria infection are primarily located in which part of the female Anopheles mosquito before inoculation?
A.
Midgut epithelium
B.
Malpighian tubules
C.
Salivary glands
D.
Ovaries
Correct Answer:
Salivary glands
Explanation:
After development in the mosquito, mature sporozoites migrate to and accumulate in the salivary glands, from where they are inoculated during feeding.
3. Which sequence most accurately describes the immediate route of Plasmodium sporozoites after their inoculation into a human host?
A.
Salivary gland to intestine to red blood cells
B.
Skin or dermis to circulation to liver
C.
Skin to red blood cells to mosquito midgut
D.
Liver to skin to red blood cells
Correct Answer:
Skin or dermis to circulation to liver
Explanation:
Sporozoites are deposited in the skin during the mosquito bite, enter the circulation or lymphatic pathways, and then reach hepatocytes in the liver.
4. Why does interruption of the mosquito's salivary-gland sporozoite load prevent malaria transmission to a human during a bite?
A.
Gametocytes cannot form in human red blood cells
B.
The mosquito cannot inoculate the human-infective stage
C.
Merozoites cannot invade the mosquito midgut
D.
Ookinetes cannot penetrate the mosquito stomach
Correct Answer:
The mosquito cannot inoculate the human-infective stage
Explanation:
Sporozoites in the salivary glands are the stage injected into humans. Without them, the bite does not directly introduce the stage that initiates human infection.
5. A researcher detects Plasmodium sporozoites in the proboscis-associated salivary glands of an Anopheles mosquito. What is the most direct biological implication?
A.
The mosquito can transmit infection to a human during feeding
B.
The mosquito has just ingested infected red blood cells
C.
The mosquito has become infected by ingesting human sporozoites
D.
The parasite has completed asexual multiplication in human erythrocytes
Correct Answer:
The mosquito can transmit infection to a human during feeding
Explanation:
Presence of sporozoites in the salivary glands indicates that the mosquito has reached the transmissible stage capable of inoculating a human during a blood meal.
6. Which statement best distinguishes sporozoite inoculation from the stage acquired by a mosquito from an infected human?
A.
Sporozoites are inoculated into humans, whereas gametocytes are taken up by mosquitoes
B.
Sporozoites are taken up by mosquitoes, whereas gametocytes are inoculated into humans
C.
Merozoites are inoculated into humans, whereas sporozoites are taken up by mosquitoes
D.
Ookinetes are inoculated into humans, whereas merozoites are taken up by mosquitoes
Correct Answer:
Sporozoites are inoculated into humans, whereas gametocytes are taken up by mosquitoes
Explanation:
During a mosquito bite, sporozoites pass from mosquito to human. During feeding on an infected person, the mosquito ingests sexual stages called gametocytes.
7. If a mosquito injects saliva but no Plasmodium sporozoites while feeding, which conclusion is most appropriate?
A.
The person must develop malaria because saliva alone contains merozoites
B.
The bite cannot initiate malaria through sporozoite inoculation
C.
The person will immediately produce gametocytes
D.
The mosquito has necessarily transmitted an ookinete
Correct Answer:
The bite cannot initiate malaria through sporozoite inoculation
Explanation:
Saliva alone does not provide the parasite stage required to initiate infection. Transmission through the bite depends on inoculation of sporozoites.
8. Which feature of the mosquito's feeding process is directly relevant to sporozoite inoculation?
A.
Regurgitation of sporozoites from salivary glands into the bite site
B.
Excretion of gametocytes through Malpighian tubules
C.
Injection of merozoites formed in the mosquito ovary
D.
Release of ookinetes from the mosquito's respiratory system
Correct Answer:
Regurgitation of sporozoites from salivary glands into the bite site
Explanation:
During feeding, sporozoites associated with the salivary apparatus are introduced into the host at the bite site, initiating the vertebrate phase of infection.
9. A vaccine blocks the ability of Plasmodium sporozoites to leave the mosquito's salivary glands. Which event would be prevented most directly?
A.
Inoculation of the human host during a mosquito bite
B.
Formation of zygotes in the mosquito stomach
C.
Ingestion of gametocytes by the mosquito
D.
Asexual multiplication inside human red blood cells
Correct Answer:
Inoculation of the human host during a mosquito bite
Explanation:
Sporozoites must reach the mosquito's saliva and be delivered during feeding. Preventing their release blocks the inoculation step specifically.
10. Which pairing correctly identifies the vector, the inoculated stage, and the initial target organ in human malaria infection?