CBSE Class 12 Biology HOTs Biology in Human Welfare

CBSE Class 12 Biology HOTs Biology in Human Welfare

Q.1 All human beings have Proto oncogenes.
But all of them do not suffer from cancer. Why? (1)
Hint. Proto oncogene does not express itself.
Q.2. Do you agree that infected cells of our body can protect the non infected cells? If yes, how?
Hint.Through interferons (1)
Q..3Why is it organ transplantation always done between very close relatives? (1)
Hint.Histocompatability to be seen
Q.Q.. Against which diseases does the MMR vaccine give protection? (1)
Ans.Measels, Mumps, Rubeolla
Q.6. Expand NACO. (1)
Ans. National AIDS control Organization
Q.7. Which day is observed as World AIDS Day? (1)
Ans. December 1
Q.8. Name the disease that is caused due to abnormal increase in Lymphocytes of blood. (1)
Ans. Leukemia/Blood cancer
Q.9. A person suffering from Elephantiasis has an abnormally increased swelling in his lower limbs. What could be the reason for the swelling?
Hint: Affect on the lymphatic vessels.
Q.10. Why do sports persons often fall victims to Cocaine addiction. (2)
Hint; Effect on CNS – increase in energy
Q.11. Chewing of Tobacco causes increase in blood pressure. Justify. (2)
Hint: Role of nicotine.
Q.12. Complete the blank spaces: (2)
Type of pathogen                   Name of pathogen                      symptoms                           Disease name
I) a ---------------                     Entamoeba                            Abdominal pain                    b . -------------
II) Bacteria                             c. ------------                           Respiratory problem            d. --------------
Q.13. Why should one take an immuno suppressants agent all through his life after an organ transplantation?(2)
Hint: Body able to differentiate the self and non-self at any time and reject the grafted the part.
Q.14. Complete the following. (2)
TB:Airborne :: Malaria: ---------
Colostrum : Passive immunity :: Vaccine : -----------
Q.15. Master X has the habit of taking pain killers for mild headache. He is advised not to take painkillers frequently by his family doctor. What could be the probable reason.
Q.16. Classify the following drugs into their respective groups (2)
Smack, Hashish, Heroin and Charas
Ans: Opioids and Cannabinoids
Q.15. What do you mean by Red Ribbon Express? (2)
Express train launched by Indian Railways recently to create awareness about AIDS. This train was taken all over India and stationed at different Junctions.
Q.16. A person suffers from dry, scaly lesions on his skin, nails and scalp which is accompanied by intense itching.
i. What is the disease he is suffering from?
ii. How would he have contracted the disease?

17. How do drugs cause addiction to a person who consumes them? (3)
Q.18. Immune system has memory component. How does man make use of it to control disease? (3)
Q.19. Classify the following under the four types of barriers in innate immunity.(3)
P M N L neutrophils
Saliva in mouth
Acid in Stomach
Mucous coating in Windpipe
Natural killer cells
Q.20. A person has been biten by a poisonous snake. He is rushed to the doctor for an urgent immune response.(3)
a) What did the doctor immediately do?
b) What kind of immunisation was he provided to get immediate response?
c) Define this kind of immunity.
Q.21.. Differentiate between a depressant and a stimulant (3 points) (3)
Q.22. State few very effective measures recently taken by the Ministry of Health to control the use of Cigarette.
Q.23.. B-Lymphocytes form humoral immune system. Justify. (3)
Hint: B-lymphocytes – plasma cells – antibodies – circulate in blood (body fluid)
Q.24. Differentiate B Cells and T Cells (3)
Q.25. Distinguish the Primary response and Secondary response. (3)
Q.26. Go through the statements and complete the sequence. (3)
Mosquito bites a healthy human and injects Sporozoites.
Sporozoites reach the a) ------------ through b) --------------
Reproduces c) --------------- burst the cells and release into blood.
Enter the d) ----------------
Reproduce asexually and release by bursting.
The cell release e) ---------- responsible for fever
Some of them form -------- that are picked by mosquito when it bites.
(Refer NCERT text book page 148/Fig 8.1)
Q.27. Explain the mode of action of the following: (3 marks)
a) Opioids b) Cannabinoids c) Cocaine



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