Biology MCQ, Class-12, Chapter-7, Human Health and Disease

NCERT based Biology MCQ of Class 12th, Chapter-7, Human Health and Disease with brief explanation for competitive exams like TGT HTET, KVS PGT, SSC and all other state competition exams. 

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Science MCQ, Class 10th, Chapter-14, Sources Of Energy

NCERT Based MCQ with Explanation:

1. What is the causative agent of typhoid fever?

(a) Streptococcus pneumoniae

(b) Salmonella typhi

(c) Plasmodium falciparum

(d) Rhinovirus

Explanation: Salmonella typhi is a pathogenic bacterium that causes typhoid fever in humans. It enters the small intestine through contaminated food and water and can spread to other organs via the blood

2. Which of the following is NOT a symptom of typhoid fever?

(a) Sustained high fever

(b) Weakness

(c) Nasal congestion

(d) Loss of appetite

Explanation: Nasal congestion is a symptom of the common cold caused by rhinoviruses, not typhoid fever. Typhoid symptoms include high fever, weakness, and loss of appetite

3. How is pneumonia primarily transmitted?

(a) Through contaminated food

(b) By mosquito bites

(c) By inhaling droplets from an infected person

(d) Through direct skin contact

Explanation: Pneumonia, caused by bacteria like Streptococcus pneumoniae, is transmitted by inhaling droplets or aerosols released by an infected person

4. Which protozoan causes malignant malaria?

(a) Plasmodium vivax

(b) Plasmodium malariae

(c) Plasmodium falciparum

(d) Ascaris lumbricoides

Explanation: Plasmodium falciparum is identified as the cause of malignant malaria, which is the most serious and potentially fatal form

NCERT Based Biology 11th MCQ with PDF

5. What is the vector for malaria?

(a) Female Aedes mosquito

(b) Female Anopheles mosquito

(c) Housefly

(d) Tsetse fly

Explanation: The female Anopheles mosquito transmits the Plasmodium parasite, which causes malaria, by biting humans

6. Which type of immunity is present at birth?

(a) Acquired immunity

(b) Innate immunity

(c) Passive immunity

(d) Active immunity

Explanation: Innate immunity is a non-specific defense mechanism present at birth, consisting of barriers like skin and mucus

7. Which of the following is a physical barrier of innate immunity?

(a) Antibodies

(b) Skin

(c) T-lymphocytes

(d) Interferons

Explanation: Skin acts as the main physical barrier preventing the entry of microorganisms

8. What type of cells produce antibodies in acquired immunity?

(a) T-lymphocytes

(b) B-lymphocytes

(c) Macrophages

(d) Neutrophils

Explanation: B-lymphocytes produce antibodies in response to pathogens, forming the humoral immune response

9. What is the main characteristic of acquired immunity?

(a) Non-specific defense

(b) Lack of memory

(c) Memory of previous encounters

(d) Immediate response

Explanation: Acquired immunity is pathogen-specific and characterized by memory, enabling a stronger response upon re-exposure

10. Which immunoglobulin is abundant in colostrum?

(a) IgG

(b) IgA

(c) IgM

(d) IgE

Explanation: Colostrum, the yellowish fluid from the mother, contains abundant IgA antibodies to protect the newborn

11. What does AIDS stand for?

(a) Autoimmune Deficiency Syndrome

(b) Acquired Immuno Deficiency Syndrome

(c) Acute Infectious Disease Syndrome

(d) Adaptive Immune Disorder Syndrome

Explanation: AIDS stands for Acquired Immuno Deficiency Syndrome, indicating an acquired immune system deficiency

12. Which virus causes AIDS?

(a) Rhinovirus

(b) Human Immunodeficiency Virus(HIV)

(c) Hepatitis B Virus

(d) Plasmodium

Explanation: AIDS is caused by HIV, a retrovirus that targets the immune system

13. How does HIV primarily enter the body?

(a) Through casual contact

(b) Via sexual contact with an infected person

(c) By eating contaminated food

(d) Through airborne droplets

Explanation: HIV transmission occurs mainly through sexual contact, blood transfusion, needle sharing, or from mother to child

14. Which cells does HIV primarily attack?

(a) B-lymphocytes

(b) Helper T-lymphocytes

(c) Macrophages

(d) Red blood cells

Explanation: HIV replicates in and destroys helper T-lymphocytes, leading to immune deficiency

15. What is a common diagnostic test for AIDS?

(a) Widal test

(b) ELISA

(c) Biopsy

(d) MRI

Explanation: The enzyme-linked immunosorbent assay(ELISA) is widely used to diagnose AIDS by detecting HIV antibodies

16. What property do cancer cells lack that normal cells possess?

(a) Metastasis

(b) Contact inhibition

(c) Rapid division

(d) Nutrient competition

Explanation: Normal cells exhibit contact inhibition, stopping growth upon contact with other cells, while cancer cells lack this, leading to uncontrolled growth

Biology MCQ, Class-11th, Chapter-19, Chemical Coordination and Integration

17. Which type of tumor can spread to distant sites?

(a) Benign

(b) Malignant

(c) Neoplastic

(d) Non-invasive

Explanation: Malignant tumors grow rapidly, invade surrounding tissues, and metastasize to distant sites, unlike benign tumors

18. What is a common physical carcinogen?

(a) Tobacco smoke

(b) UV radiation

(c) Plasmodium

(d) Salmonella typhi

Explanation: UV radiation, a non-ionizing radiation, is a physical carcinogen causing DNA damage

19. Which technique uses X-rays to detect internal cancers?

(a) MRI

(b) Computed Tomography(CT)

(c) ELISA

(d) Vaccination

Explanation: CT uses X-rays to create 3D images of internal organs, aiding cancer detection

20. What is metastasis in the context of cancer?

(a) Controlled cell growth

(b) Spread of cancer cells to distant sites

(c) Formation of benign tumors

(d) Immune system activation

Explanation: Metastasis is the process where malignant tumor cells spread to distant body sites via blood

21. Which plant is the source of morphine?

(a) Cannabis sativa

(b) Papaver somniferum

(c) Erythroxylum coca

(d) Atropa belladona

22. What is the primary effect of cocaine on the body?

(a) Depressant

(b) Stimulant

(c) Sedative

(d) Analgesic

23. Which substance in tobacco increases blood pressure?

(a) Carbon monoxide

(b) Nicotine

(c) Tar

(d) Caffeine

24. What age range is typically considered adolescence?

(a) 5-10 years

(b) 12-18 years

(c) 20-25 years

(d) 30-35 years

25. What is a common sign of drug abuse among youth?

(a) Improved academic performance

(b) Increased interest in hobbies

(c) Drop in academic performance

(d) Better family relationships

26. Who was known as "Typhoid Mary"?

(a) A scientist who discovered typhoid

(b) A typhoid carrier who spread the disease

(c) A doctor who cured typhoid

(d) A vaccine developer

27. What is the role of interferons in immunity?

(a) Produce antibodies

(b) Protect non-infected cells from viral infection

(c) Phagocytose microbes

(d) Trap antigens

28. Which disease is caused by the filarial worm Wuchereria?

(a) Malaria

(b) Elephantiasis

(c) Typhoid

(d) Ringworm

29. What is the primary lymphoid organ where lymphocytes mature?

(a) Spleen

(b) Thymus

(c) Lymph nodes

(d) Appendix

30. Which of the following is a fungal disease?

(a) Typhoid

(b) Ringworm

(c) Malaria

(d) Pneumonia

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