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CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 3 Marks Questions 2021

Published on: 28/05/2021

QB365 Provides the HOT Question Papers for Class 12 Biology, and also provide the detail solution for each and every HOT Questions. HOT Questions will help to get more idea about question pattern in every exams and also will help to get more marks in Exams

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Std: 12th Standard CBSE - Biology

chapter: - HOT Questions

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Questions:

Generic 3

5 x 3 = 15

List the causative organism and carrier of the following diseases.
(i) Dengue fever
(ii) Chikungunya

A thalasemic child needed repeated blood transfusions, got infected by HIV.
(i) use a rough diagramatic sketch and arrows to show how the virus increased in number.
(ii) Why did the increased number of HIV viruses deteriorate the child's immunity?
(iii) Which diagnostic test showed that the infective virus was HIV?

Given below are pairs of disease and causative organism. Which out of these is not these is not a matching pair and why?
Filariasis : Wuchereria
Ringworm : Ascaris
AIDS : Human Immunodeficiency virus
Malaria : Plasmodium

Think what two measures should be taken for prevention and control of alcohol and drug abuse among adolescents

(a) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body,when bitten by female Anopheles? Explain.
(b) Give the scientific name of the malarial parasite that causes malignant malaria in humans .

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Answers Key:

Generic 3

5 x 3 = 15

(i) Flavi-ribo virus is causative organism.
Aedes aegypti mosquito is carrier.
(ii) Alpha virus (Chikungunya virus) - causative organism Aedes aegypti mosquito is carrier.

(i)
(ii) The macrophages continue to produce virus. HIV enter into helper T lymphocytes, replicate and produce progeny viruses. Progeny virus lyse the host cell to attack other helper T lymphocytes. This is repeated and as a result there is decrease in number of helper T lymphocytes in the infected person.
(iii) Widely used diagnostic test for AIDS is ELISA (Enzyme linked Immunosorbent Assay)

AIDS -Human Immunodeficiency Virus. It is because all diseases are vector-borne diseases and AIDS is through a virus.

(i) Avoiding undue pressure on adolescents.
(ii) Seeking professional and medical help.

(a) It takes time for the symptoms for the following reasons.
(i) The parasite reaches the liver cells,reproduces asexually and comes out by bursting the liver cells.
(ii) Such cells enter the red blood cells,multiply and come out of RBCs by bursting them.
(iii) The rupture of RBCs releases haemozoin,which produces the disease symptoms.
(b) Plasmodium falciparum.