Kerala SSLC · Biology · Class 10

Keeping Diseases Away: Important Questions with Answers

These are 10 important multiple-choice questions from the Kerala SSLC Biology chapter “Keeping Diseases Away” (Kerala SCERT syllabus). Each one shows the correct answer and a short explanation of why it is right. Try answering before you read the answer. ExamSummary has 10 practice questions on this chapter in total.

  1. Q1.Which characteristic primarily defines an infectious disease?

    • A)It is caused by genetic mutations.
    • B)It can be transmitted from person to person.
    • C)It requires surgery for treatment.
    • D)It develops due to environmental pollution.

    Answer: B) It can be transmitted from person to person.

    Infectious diseases are caused by pathogens like bacteria or viruses and are characterized by their ability to spread between individuals. Genetic mutations and pollution typically lead to non-infectious conditions.

  2. Q2.How does vaccination protect the human body against future infections?

    • A)By killing all existing pathogens in the blood.
    • B)By stimulating the immune system to produce antibodies.
    • C)By increasing the number of red blood cells.
    • D)By permanently altering the DNA of the host.

    Answer: B) By stimulating the immune system to produce antibodies.

    Vaccines introduce a harmless version of a pathogen to train the immune system to recognize and fight the actual disease later. This process creates memory cells that enable a rapid response upon future exposure.

  3. Q3.Identify the vector responsible for transmitting the malaria parasite.

    • A)Female Anopheles mosquito
    • B)Male Anopheles mosquito
    • C)Aedes mosquito
    • D)Housefly

    Answer: A) Female Anopheles mosquito

    Malaria is transmitted specifically by the bite of the infected female Anopheles mosquito, which carries the Plasmodium parasite. Other mosquitoes like Aedes transmit dengue, while houseflies spread food-borne illnesses.

  4. Q4.A person who has recovered from measles possesses which type of immunity?

    • A)Natural passive immunity
    • B)Artificial active immunity
    • C)Natural active immunity
    • D)Artificial passive immunity

    Answer: C) Natural active immunity

    Recovering from a natural infection stimulates the body's own immune system to create lasting memory cells. This results in natural active immunity, unlike artificial methods involving injections or passive transfer via antibodies.

  5. Q5.Which virus is the causative agent of Acquired Immune Deficiency Syndrome (AIDS)?

    • A)Hepatitis B Virus (HBV)
    • B)Human Immunodeficiency Virus (HIV)
    • C)Influenza Virus
    • D)Herpes Simplex Virus

    Answer: B) Human Immunodeficiency Virus (HIV)

    HIV attacks the body's immune system, specifically CD4 cells, eventually leading to AIDS where the body cannot fight off opportunistic infections. HBV affects the liver, while influenza causes respiratory illness.

  6. Q6.Which of the following diseases is caused by a bacterium rather than a virus or parasite?

    • A)Malaria
    • B)Tuberculosis
    • C)Dengue
    • D)Polio

    Answer: B) Tuberculosis

    Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. Malaria is parasitic, while Dengue and Polio are caused by viruses.

  7. Q7.Why is boiling drinking water considered a crucial public health measure?

    • A)It removes dissolved salts from the water.
    • B)It kills pathogenic microorganisms present in the water.
    • C)It changes the pH level of the water to alkaline.
    • D)It adds essential minerals to the water supply.

    Answer: B) It kills pathogenic microorganisms present in the water.

    Boiling raises the temperature high enough to denature proteins in bacteria and viruses, effectively killing them. This prevents waterborne diseases like cholera and typhoid from spreading through consumption.

  8. Q8.Antibiotics are prescribed for bacterial infections but not for viral fevers because...

    • A)Viruses reproduce faster than bacteria.
    • B)Antibiotics target bacterial cell structures absent in viruses.
    • C)Viruses are larger than bacteria.
    • D)Antibiotics weaken the immune system against viruses.

    Answer: B) Antibiotics target bacterial cell structures absent in viruses.

    Antibiotics function by disrupting bacterial cell walls or metabolic pathways that viruses do not possess since they rely on host cells. Using them for viral infections is ineffective and contributes to antibiotic resistance.

  9. Q9.Eliminating stagnant water around homes is recommended primarily to control the spread of which disease?

    • A)Tuberculosis
    • B)Diabetes
    • C)Dengue
    • D)Hypertension

    Answer: C) Dengue

    Dengue fever is transmitted by the Aedes mosquito, which lays eggs in stagnant water sources. Removing these breeding grounds interrupts the mosquito life cycle and reduces disease transmission.

  10. Q10.Administration of anti-rabies serum immediately after a dog bite provides which type of immunity?

    • A)Natural active immunity
    • B)Artificial active immunity
    • C)Natural passive immunity
    • D)Artificial passive immunity

    Answer: D) Artificial passive immunity

    Anti-rabies serum contains pre-formed antibodies injected into the patient to provide immediate protection without the body generating them. This is classified as artificial passive immunity because it is externally sourced and temporary.

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