CBSE 2024 · Region 5 · Set 1 · Q30 · 4 marks
Read the following passage and answer the questions that follow : "Mosquitoes are drastically affecting the human health in almost all the developing tropical countries. Different species of mosquitoes cause very fatal diseases so much so that many humans loose their life and if they survive, are unable to put in productive hours to sustain their life. With the result the health index of the country goes down."(a)Name the form in which Plasmodium gains entry into (i) human body (ii) the female Anopheles body.Why do the symptoms of malaria not appear in a person immediately after being bitten by an infected female Anopheles ? Give one reason. Explain when and how do the symptoms of the disease would appear.Explain the events which occur within a female Anopheles mosquito after it has sucked blood from a malaria patient.(c)Name a species of mosquito other than female Anopheles and the disease, for which it carries the pathogen.
Read the following passage and answer the questions that follow : "Mosquitoes are drastically affecting the human health in almost all the developing tropical countries. Different species of mosquitoes cause very fatal diseases so much so that many humans loose their life and if they survive, are unable to put in productive hours to sustain their life. With the result the health index of the country goes down."
(a)
Name the form in which Plasmodium gains entry into (i) human body (ii) the female Anopheles body.
Why do the symptoms of malaria not appear in a person immediately after being bitten by an infected female Anopheles ? Give one reason. Explain when and how do the symptoms of the disease would appear.
Explain the events which occur within a female Anopheles mosquito after it has sucked blood from a malaria patient.
(c)
Name a species of mosquito other than female Anopheles and the disease, for which it carries the pathogen.
Marking-scheme solution
(i)
Sporozoites, (ii) gametocytes
• The sporozoites after entering the body need to undergo asexual
reproduction in liver and RBC
• RBC burst, released haemozoin which is responsible for chill and
high fever recurring every $\displaystyle 3$-$\displaystyle 4$ days.
Gametocytes (male and female) enter female mosquito body via blood meal,
fertilization in gut / stomach, sporozoites escape from the gut, and migrate into salivary glands (of mosquito)
(c)
Aedes, - dengue / chikungunya or Culex, - filariasis or elephantiasis
Human Health and DiseaseCommon Diseases in HumansUnderstandcase_studymedium
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CBSE Class 12 Biology past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.